G oup 3 and G oup 13 Me al Hyd ide Compounds
DISSERTATION
zu E langung des akademischen G ades eines
Dok o s de Na u wissenscha en (D . e . na .)
im Fach Chemie de Fakul ä ü Biologie, Chemie und Geowissenscha en
de Uni e si ä Bay eu h
o geleg on
Dipl. Chem. Tobias Baue
gebo en in Regensbu g
Bay eu h, 2013
G oup 3 and G oup 13 Me al Hyd ide Compounds
DISSERTATION
zu E langung des akademischen G ades eines
Dok o s de Na u wissenscha en (D . e . na .)
im Fach Chemie de Fakul ä ü Biologie, Chemie und Geowissenscha en
de Uni e si ä Bay eu h
o geleg on
Dipl. Chem. Tobias Baue
gebo en in Regensbu g
Bay eu h, 2013
The ollowing wo k has been ca ied ou in he pe iod Sep embe 2009 o July 2013 a
he Leh s uhl ü Ano ganische Chemie II o he Uni e si ä Bay eu h unde he
supe ision o P o . D . Rhe Kempe.
This hesis ul ills he equi emen s o he doc o al deg ee o he Falkul ä ü Biologie,
Chemie und Geowissenscha en a he Uni e si ä Bay eu h.
Thesis submi ed: 03/07/2013
Thesis accep ed: 10/07/2013
Scien i ic Colloquium: 31/10/2013
Cu en dean o acul y:
P o . D . Rhe Kempe
Examina ion Commi ee:
Fi s e e ee: P o . D . R. Kempe
Second e e ee: P o . D . R. Schobe
Thi d e e ee: P o . D . A. Fe y
Chai man: P o . D . A. G eine

„Das Auße o den liche geschieh nich au gla em, gewöhnlichem Wege.“
Johann Wol gang on Goe he
Alphabe ical lis o abb e ia ions
alane aluminum hyd ide
Ap aminopy idina e, aminopy idina o ligand
ApH aminopy idine
°C deg ee celsius
Cp cyclopen adienyl ligand
ELI-D elec on localizabili y indica o
E e hyl
Gu guanidina e, guanidina o ligand
GuH guanidine
NMR nuclea magne ic esonance spec oscopy
h /THF e ahyd o u an
PE 3 ie hylphosphine
Ph phenyl
py py idinyl
PyAp dep o ona ed N-(2,6-diisop opylphenyl)-6-(py olidin-1-yl)py idin-2-amine
QTAIM quan um heo y o a oms in molecules
XRD single c ys al X- ay s uc u e analysis
Table o Con en s
1 Summa y/Zusammen assung ............................................................. 1
1.1 Summa y .................................................................................................... 1
1.2 Zusammen assung .................................................................................... 4
2 In oduc ion ......................................................................................... 7
3 O e iew o Thesis Resul s .............................................................. 13
3.1 Synopsis ................................................................................................... 13
3.2 Indi idual Con ibu ion o Join Publica ions ....................................... 19
4 The Ligand-Based Quin uple Bond-Sho ening Concep and Some
o I s Limi a ions ..................................................................................... 21
4.1 In oduc ion .............................................................................................. 22
4.2 Resul s and Discussion .......................................................................... 23
4.3 Conclusions ............................................................................................. 32
4.4 Expe imen al Sec ion .............................................................................. 32
4.5 Acknowledgmen s ................................................................................... 36
4.6 Re e ences ............................................................................................... 36
4.7 Suppo ing In o ma ion ........................................................................... 40
4.8 Re e ences ............................................................................................... 45
5 Syn hesis and S uc u e o Aminopy idina o and Guanidina o
Ligand S abilized Al-H Complexes ........................................................ 46
5.1 In oduc ion .............................................................................................. 46
5.2 Resul s and Discussion .......................................................................... 47
5.3 Conclusions ............................................................................................. 53
5.4 Expe imen al Sec ion .............................................................................. 54
5.5 Re e ences ............................................................................................... 56
6 Syn hesis and S uc u e o a T inuclea Y ium Polyhyd ide
Clus e S abilized by a Bulky Guanidina o Ligand ............................... 58
6.1 In oduc ion .............................................................................................. 58
6.2 Resul s and Discussion .......................................................................... 59
6.3 Conclusions ............................................................................................. 65
6.4 Acknowledgmen s ................................................................................... 66
6.5 Expe imen al Sec ion .............................................................................. 66
6.6 Re e ences ............................................................................................... 67
7 Te na y Ra e-Ea h T ansi ion-Me al Polyhyd ide Clus e
Compounds ............................................................................................. 69
7.1 In oduc ion .............................................................................................. 69
7.2 Resul s and Discussion .......................................................................... 70
7.3 Conclusions ............................................................................................. 75
7.4 Acknowledgmen s ................................................................................... 75
7.5 Re e ences ............................................................................................... 76
7.6 Suppo ing In o ma ion ........................................................................... 78
7.7 Gene al ..................................................................................................... 78
7.8 De ails o he X- ay c ys al s uc u e analyses ..................................... 79
7.9 Syn hesis and cha ac e iza ion o he clus e compounds ................. 80
7.10 Re e ences ............................................................................................... 81
8 Lis o Publica ions ........................................................................... 82
9 Acknowledgemen s / Danksagung ................................................... 85
9.1 Acknowledgmen s ................................................................................... 85
9.2 Danksagung ............................................................................................. 87
10 Decla a ion / E klä ung: .................................................................... 89
2. In oduc ion
7
2 In oduc ion
Me al-ca bon and me al-hyd ogen bonds a e a he e y hea o coo dina ion chemis y.
Molecula me al hyd ides, in gene al, a e a ascina ing class o compounds ega ding hei
s uc u e, eac i i y and applica ions. They a e key in e media es in a ple ho a o selec i e
s oichiome ic ans o ma ions and/o ca aly ic cycles. The i s well-de ined ansi ion me al
hyd ides, (CO)4FeH2 and (CO)4CoH, we e p epa ed by Hiebe and co-wo ke s in 1931 and
1932, espec i ely.[1,2] These qui e uns able compounds emained as labo a o y cu iosi ies o
o e 20 yea s. The nex miles one da es back o he yea 1955 wi h he disco e y o (C5H5)2ReH
by Bi mingham and Wilkinson[3] and (C5H5)(CO)3MH (M = C , Mo, W) by Fische and co-
wo ke s.[4] Two yea s la e , Cha , Duncanson, and Shaw p epa ed he excep ionally s able
hyd ide compound ans-(PE 3)2ClP H.[5] Since hen, apid de elopmen in his ield ook place
and by he yea 1965 o e 200 de i a i es we e epo ed in some 300 publica ions.[6] In 2001
he Nobel P ize in chemis y was awa ded join ly o Knowles, Nyo i and Sha pless o
asymme ic ca alysis (Knowles and Nyo i o con ibu ions on asymme ic hyd ogena ion). This
can be seen as one magic momen o me al hyd ide chemis y.
Resea ch in e es in he main g oup me al hyd ides was documen ed alike.[7] The s-block
me al hyd ides a e sal -like and he p-block me al hyd ides o m co alen ly bonded molecules
compa able o he ones o med by he d- and -block me als. Especially aluminum hyd ides, i s
p epa ed by S eche and Wibe g in 1942,[8] ecei ed much a en ion due o p omising
applica ions as educing agen s in o ganic syn hesis[9] and o he educ ion o me al
complexes[10]. Fu he mo e, alanes a e used in hyd oamina ion eac ions[11] and as p ecu so s
o me al o ganic chemical apo deposi ion p ocesses.[12] A mo e con enien p epa a ion
me hod was epo ed by Finhol , Bond, and Schlesinge in 1947.[13] Pionie ing wo k on amine
complexes o alane da es back o he ea ly 1950s and he ea ly 1960s.[14,15] Since hen, much
e o has been de o ed o ex end he ield o alane chemis y. T ansi ion me al σ-alane
complexes[16] we e p epa ed due o p omising applica ions. Recen s udies on alanes ocus on
applica ions as hyd ogen s o age ma e ials.[17,18] Mo eo e , a guanidina o ligand s abilized
adduc o dialane (Al2H4) was epo ed o ea u e a di ec Al-Al bond.[19]
Ano he p ominen and ich ield o me al hyd ides is ound o be he hyd ides o a e
ea h me als (g oup 3 me als and lan hanoid me als [Ce-Lu]). These compounds o en
agg ega e and build up polyhyd ide clus e s. Ra e ea h (poly)hyd ide compounds possess a
ascina ing a ie y o unique s uc u al mo i s and chemical p ope ies. The ea ly wo k on
lan hanoid hyd ides is e iewed by Bos and Gaye and co e s he pe iod om 1891 o 1966.[20]

2. In oduc ion
8
Since hen, i ook o e a decade un il he i s example o a molecula lan hanoid hyd ide was
epo ed. Schumann and co-wo ke s p epa ed [(C5H5)2LuH( h )] ( h = e ahyd o u an) by
hyd ogenolysis o he co esponding alkyl o a yl p ecu so in 1981.[21] F om he e on, esea ch
in e es inc eased and an oddless numbe o cyclopen adienyl s abilized hyd ide and alkyl
complexes o he a e ea hs became known.[22] Va ious applica ions and eac i i ies like
hyd ogena ion eac ions,[23] hyd obo a ion eac ions,[24] hyd oamina ion eac ions,[25]
hyd osilyla ion eac ions,[26] hyd ophosphina ion eac ions[27] and polyme iza ion p ocesses[28] o
alkenes by cyclopen adienyl- ype a e ea h me al hyd ides and alkyls a e published. Hence,
pe manen in e es in his ype o compounds a ose. Recen ly, a shi om cyclopen adienyl
ligand sandwich- and hal -sandwich (poly)hyd ide complexes owa ds al e na i ely suppo ed
hyd ide compounds has aken place.[29] Mainly, because o hei p omising new applica ions and
eac i i ies. None heless, a e ea h me al hyd ide compounds suppo ed by ligands o he han
Cp and i s de i a i es s ill lack in numbe .
The mos used and impo an Cp al e na i es a e amido[30] (Scheme 1, igh ) and alkoxy
ligands (Scheme 1, cen e ). They ha e p o en o be sui able o he s abiliza ion o elec on
poo ansi ion, main g oup and a e ea h me al ions in di e en oxida ion s a es.
Scheme 1. Commonly used ligand ypes o he s abiliza ion o me al hyd ides (R, R’ = a yl, alkyl o silyl, M = Main
g oup, ansi ion o a e ea h me al).
The aminopy idina o ligand, a subclass o he amido ligand amily, de i ed om
dep o ona ed 2-aminopy idines, has been p ominen ly used in he enaissance o amido me al
chemis y.[31] Two di e en binding modes a e known (Scheme 2) and many subs i u ion
pa e ns o ine une he s e ic bulk o he ligand a e possible. S a ing om 2,6-dib omopy idine,
i s ly a subs i u ed phenyl g oup is in oduced ia Kumada coupling and secondly, a de i a i e
o aniline is in oduced ia Buchwald-Ha wig a yl amina ion.
Scheme 2. Binding modes o aminopy idina o ligands (R, R' = a yl, alkyl o silyl, M = Main g oup, ansi ion o a e
ea h me al, M' = ansi ion me al).
2. In oduc ion
9
[Ru(PhNpy)2)PPh3)2] was he i s example o a s ained η2-coo dina ed aminopy idina o
ligand s abilized complex, desc ibed by Co on and co-wo ke s in 1984.[32] In 1991 Gamba o a
and co-wo ke s epo ed on he i s anadium compound s abilized by an aminopy idina o
ligand.[33] Kempe e al. p epa ed he i s co esponding g oup 3 me al complex in 1997.[34]
Ano he subclass o he amido ligands a e guanidina o ligands de i ed om
dep o ona ed guanidines, which a e compa able o he aminopy idina o ligands ega ding hei
binding mode (Scheme 3). Thei subs i u ion pa e n is mo e a iable han o he
aminopy idina o ligands, due o subs i u ion on he ni ogen a oms. Recen ly, his ligand class
was comp ehensi ely e iewed by Jones.[35] Syn hesis o guanidina o ligands is achie ed ia a
di ec app oach s a ing om subs i u ed ca bodiimides, which a e eac ed, wi h li hia ed
seconda y amine de i a i es. The esul ing li hium complexes o he ligands can be used in sal
me a hesis eac ions owa ds me al halides o can be hyd olyzed o a o d he p o ona ed
ligands. These p o ona ed ligands can be used in alkane o amine elimina ion ou es. Lappe
and co-wo ke s published he i s ansi ion me al guanidina o ligand s abilized complex in
1970.[36]
Scheme 3. Binding modes o guanidina o ligands (R, R',R'', R''' = a yl, alkyl o silyl, M = Main g oup, ansi ion o a e
ea h me al, M' = ansi ion me al).
Fi s ly, his wo k was ocused on syn hesis and cha ac e iza ion o guanidina o ligand
s abilized aluminum dime hyl complexes. These complexes we e examined ega ding he
subs i uen s R'' and R'''. Dependency o he s e ic bulk owa ds he (M)N-C-N(M) angle was
obse ed (Scheme 3, le , M = Al).
Secondly, syn hesis and s uc u e o Ap and Gu ligand s abilized Al-H complexes was
discussed. The eac ion o a s e ically bulky guanidine wi h li hium alana e was examined. A
a e example o a σ-alane li hium complex was obse ed.
Thi dly, a guanidina o ligand s abilized y ium dialkyl complex was syn hesized and
cha ac e ized. I s abili y owa ds hyd ogenolysis using H2 was in es iga ed. The esul ing
inuclea y ium polyhyd ide clus e compound possesses highly dynamic beha io o he
hyd ides and he guanidina o ligands, as obse ed by a iable empe a u e 1H NMR
spec oscopy.
2. In oduc ion
10
Fou hly, he i s examples o e na y a e ea h- ansi ion me al polyhyd ide clus e
compounds we e shown. Clus e o ma ion p oceeded h ough C–H bond ac i a ion o he Cp
ligands ha s abilize he ansi ion me al-con aining educ . Quan um chemical calcula ions o
he elec onic s uc u e showed ionic W–H∙∙∙Lu in e ac ions and a co alen , pola Lu–Re bond.
[1] W. Hiebe , F. Leu e , Na u wissenscha en 1931,19, 360–361.
[2] W. Hiebe , F. Mühlbaue , E. A. Ehmann, Be ich e de deu schen chemischen
Gesellscha (A and B Se ies) 1963, 65, 1090–1101.
[3] G. Wilkinson, J. M. Bi mingham, J. Am. Chem. Soc. 1955, 77, 3421–3422.
[4] E. O. Fische , W. Ha ne , H. O. S ahl, Z. Ano g. Allg. Chem. 1955, 282, 47–62.
[5] J. Cha , L. A. Duncanson, B. L. Shaw, P oc. Chem. Soc. 1957, 343.
[6] Fo selec ed e iew a icles on molecula ansi ion me al hyd ides, please see: a) J.
Cha , Science 1968, 160, 723–729; b) H. D. Kaesz, R. B. Saillan , Chem. Re . 1972,
72, 231–281; c) A. J. Hoskin, D. W. S ephan, Coo d. Chem. Re . 2002, 233–234, 107–
129; d) G. S. McG ady, G. Guile a, Chem. Soc. Re . 2003, 32, 383–392.
[7] Fo selec ed e iew a icles on main g oup me al hyd ides, please see: a) S. Ald idge, A.
J. Downs, Chem. Re . 2001, 101, 3305–3365, b) S. K. Mandal, H. W. Roesky, Acc.
Chem. Res. 2012, 45, 298–307.
[8] O. S eche , E. Wibe g, Be ich e de deu schen chemischen Gesellscha (A and B
Se ies) 1942, 75, 2003–2012.
[9] J. Málek, M. Ce ný, Syn hesis 1972, 217–234.
[10] B. M. Bulyche , Polyhed on 1990, 9, 387–408.
[11] H. Haubens ock, E. L. Eliel, J. Am. Chem. Soc. 1962, 84, 2363–2368.
[12] J. A. Jegie , W. L. Glad el e , Coo d. Chem. Re . 2000, 206–207, 631–650.
[13] A. E. Finhol , A. C. Bond, H. I. Schlesinge , J. Am. Chem. Soc. 1947, 69, 1199–1203.
[14] E. Wibe g, H. G a , R. Usón, Z. Ano g. Allg. Chem. 1953, 272, 221–232.
[15] J. K. Ru , M. F. Haw ho ne, J. Am. Chem. Soc. 1960, 82, 2141–2144.
[16] I. M. Riddles one, S. Edmonds, P. A. Kau man, J. U bano, J. I. Ba es, M. J. Kelly,
A. L. Thompson, R. Taylo , S. Ald idge, J. Am. Chem. Soc. 2012, 134, 2551−2554.
[17] a) L. Schlapbach, A. Zü el, Na u e 2001, 414, 353-358; b) E. Da id, J. Ma e . P oc.
Technol. 2005, 162, 169–177; c) U. Ebe le, M. Felde ho , F. Schü h, Angew. Chem.
2009, 121, 6732–6757; Angew. Chem. In . Ed. 2009, 48, 6608–6630, d) S. F. Ma a ,
P og. Solid S a e Chem. 2010, 38, 1-37; e) S. F. Ma a , P og. Solid S a e Chem. 2012,
40, 31–40.
[18] Fo ecen examples see: a) A. Zü el, Ma e . Today 2003, 24–33; b) M. La oche, J.
Phys. Chem. Solids 2004, 65, 517–522; c) W. G ochala, P. P. Edwa ds, Chem. Re .
2. In oduc ion
11
2004, 104, 1283–1315; d) S. Ha de , J. Spielmann, J. In emann, H. Bandmann, Angew.
Chem. 2011, 123, 4242–4246; Angew. Chem. In . Ed. 2011, 50, 4156–4160; e) P.
Jochmann, J. P. Da in, T. P. Spaniol, L. Ma on, J. Okuda, Angew. Chem. 2012, 124,
4528–4531; Angew. Chem. In . Ed. 2012, 51, 4452–4455.
[19] S. J. Bonhady, D. Collis, G. F enking, N. Holzmann, C. Jones, A. S asch, Na . Chem.
2010, 2, 865–869.
[20] W. G. Bos, K. H. Gaye , J. Nuc. Ma . 1966, 18, 1–30.
[21] H. Schumann, W. Gen he, J. O ganome . Chem. 1981, 213, C7–C9.
[22] Fo selec ed e iew a icles on cyclopen adienyl lan hanoid hyd ides, please see: a) H.
Schumann, J. A. Meese-Ma k sche el, L. Esse , Chem. Re . 1995, 95, 865–986; b) M.
Eph i ikhine, Chem. Re . 1997, 97, 2193–2242.
[23] a) W. J. E ans, I. Bloom, W. E. Hun e , J. L. A wood, J. Am. Chem. Soc. 1983, 105,
1401–1403; b) G. Jeske, H. Lauke, H. Maue mann, H. Schumann, T. J. Ma ks, J. Am.
Chem. Soc. 1985, 107, 8091–8103; c) D. S e n, M. Saba , T.J. Ma ks, J. Am. Chem.
Soc. 1990, 112, 9558–9575; d) V. P. Con icello, L. B a d, M. A. Gia dello, Y. Tsuji, M.
Saba , C. L. S e n, T. J. Ma ks, J. Am. Chem. Soc. 1992, 114, 2761–2762.
[24] a) K. N. Ha ison, T. J. Ma ks, J. Am. Chem. Soc. 1992, 114, 9220–9221; b) E. A.
Bijpos , R. Ducha eau, J. H. Teuben, J. Mol. Ca al. 1995, 95,121–128;
[25] a) P. W. Roesky, T. E. Mülle , Angew. Chem. 2003, 115, 2812–2814; Angew. Chem. In .
Ed. 2003, 42, 2708–2710; b) S. Hong, T. J. Ma ks, Acc. Chem. Res. 2004, 37, 673–686;
c) K. C. Hul zsch, Ad . Syn h. Ca al. 2005, 347, 367–391.
[26] G. A. Molande , J. A. C. Rome o, Chem. Re . 2002, 102, 2161–2186.
[27] a) M. R. Douglass, T. J. Ma ks, J. Am. Chem. Soc. 2000, 122, 1824–1825; b) A.
Kawaoka, T. J. Ma ks, J. Am. Chem. Soc. 2004, 126, 12764–12765; c) A. Kawaoka, T.
J. Ma ks, J. Am. Chem. Soc. 2005, 127, 6311–6324.
[28] a) Z. Hou, Y. Waka suki, Coo d. Chem. Re . 2002, 231, 1–22; b) H. Yasuda, J.
O ganome . Chem. 2002, 647, 128–138; c) Y. Nakayama, H. Yasuda, J. O ganome .
Chem. 2004, 689, 4489–4498.
[29] Fo selec ed e iew a icles on non-cyclopen adienyl lan hanoid hyd ides and hei
applica ions, please see: a) M. Konkol, J. Okuda, Coo d. Chem. Re . 2008, 252, 1577–
1591; b) A. A. T i ono , Coo d. Chem. Re . 2010, 254, 1327–1347.
[30] M. F. Lappe , P. P. Powe , A. R. Sange , R. C. S i as a a, Me al and Me alloid Amides,
Ellis No wood L d., Chiches e , 1980.
[31] R. Kempe, Angew. Chem. 2000, 112, 478–504; Angew. Chem. In . Ed. 2000, 39, 468–
493.
[32] A. R. Chak a a y, F. A. Co on, E. S. Shamshoum, Ino g. Chim. Ac a 1984, 86, 5–11.
2. In oduc ion
12
[33] J. J. H. Edema, S. Gamba o a, A. Mee sma, A. L. Spek, N. Veldman, Ino g. Chem.
1991,30, 2062–2066.
[34] R. Kempe, A. Spannenbe g, Z. K is alog . NCS 1997, 212, 487–489.
[35] C. Jones, Coo d. Chem. Re . 2010, 254, 1273–1289.
[36] G. Chand a, A. D. Jenkins, M. F. Lappe , R. C. S i as a a, J. Chem. Soc. 1970, 2550–
2558.

3. O e iew o Thesis Resul s
13
3 O e iew o Thesis Resul s
This hesis comp ises ou publica ions, which a e p esen ed in chap e s 4 o 7. The indi idual
con ibu ions o join publica ions a e poin ed ou in chap e 3.2. In he ollowing, he cen al
heme o he hesis is summa ized.
3.1 Synopsis
The main ask o his hesis was o inc ease he small numbe o s uc u ally ully
cha ac e ized g oup 3 and g oup 13 me al hyd ide compounds. Fu he mo e, g oup 3 and g oup
13 me al alkyl compounds we e syn hesized (and cha ac e ized). These alkyl compounds we e
syn hesized as p ecu so s and hei abili y o a o d hyd ide compounds was s udied.
Suppo ing ligands o all complexes p esen ed he ein we e es ic ed o aminopy idina o,
guanidina o and phenola o ligands. These ypes o ligands a e used o a e y sligh ex en in
g oup 3 and g oup 13 me al hyd ide chemis y. Chap e 4 deals wi h new aluminum alkyl
compounds s abilized by guanidina o ligands. Guanidina o ligand s abilized aluminum dialkyls
we e syn hesized and s uc u ally cha ac e ized. S uc u al da a o hese compounds based on
single c ys al X-Ray s uc u e analysis led o a concep o sho ening me al-me al bonds. Due o
his ligand based concep he bes sui ed ligand yielding a s able C -C compound ea u ing he
sho es me al-me al bond obse ed o da e was ound. In diguanidina o dich omium complexes
he leng h o he quin uple bond can be in luenced by he subs i uen a he cen al ca bon a om
o he used ligand. To ind he guanidina o ligand o ming he sho es C -C quin uple bonded
complex, he dependency o he ele an N-C-N angle in he guanidina o ligand om he
in oduced subs i uen was in es iga ed. Fine uning o he ligands s e ic bulk was essen ial.
Guanidina o ligand s abilized aluminum dialkyls we e expec ed o be well sui ed o such a
ligand ine- uning. The e ahed al coo dina ion a oided in e -ligand epulsion and he smoo h
syn hesis ia alkane elimina ion om aluminum ialkyls allowed o an easy access. Fou
di e en guanidina o ligand s abilized aluminium dialkyls we e syn hesized. These compounds
we e isola ed in good yields (> 80 %).
3. O e iew o Thesis Resul s
14
Figu e 3.1. C ys al s uc u e o [(MPipGu)AlMe2] and [{(MPipGu)C }2].
S uc u al da a o he co esponding aluminum dialkyls showed p omising (Al)N-C-N(Al)
angles o he guanidina o ligands bea ing a 2,6-dime hylpipe idine and a diisop opylamine
backbone, espec i ely. The ound (Al)N-C-N(Al) angles we e 107.68(12)° (2,6-
dime hylpipe idine) and 107.39(15)° (diisop opylamine). These wo po en ial ligands we e
examined owa ds ul a sho me al-me al dis ances.
Figu e 3.2.N-C-N angles o all s uc u ally in es iga ed Al complexes.
The guanidina o ligand ca ying he 2,6-dime hylpipe idine backbone was ound o be
he op imal ligand. The educ ion o i s ch omium(II) chlo ide a e-complex yielded a quin uply
bonded bime allic complex wi h a C -C -dis ance o 1.7056 (12) Å. Mo eo e , hese guanidina o
ligand s abilized aluminum dialkyls we e hough o as p ecu so s o aluminum hyd ide
3. O e iew o Thesis Resul s
15
compounds. T ans o ma ion o he alkyl compounds using H2 and phenylsilane did no a o d
he co esponding hyd ide compounds. So, a di ec app oach o molecula alanes s abilized by
N-ligands was ca ied ou . Chap e 5 deals wi h he syn hesis and s uc u e o a e
aminopy idina o and guanidina o ligand s abilized aluminum hyd ide compounds. Only a small
numbe o s uc u ally ully cha ac e ized amidina o, aminopy idina o and guanidina o ligand
s abilized alanes a e known un il now. S a ing om AlH3, he di ec app oach o a o d N-ligand
s abilized aluminum hyd ide compounds was s udied. The eac ion o he aminopy idine N-(2,6-
diisop opylphenyl)-6-(py olidin-1-yl)py idin-2-amine (PyApH) and he guanidine N,N'-bis(2,6-
diisop opylphenyl)pipe idine-1-ca boximidamide (PipGuH) wi h eshly p epa ed AlH3 was
in es iga ed. Fo bo h N-ligands he o ma ion o a dime ic, double hyd ogen b idged aluminum
dihyd ide complex was obse ed. In hese isos uc u al dime ic complexes, he aluminum
cen e s a e i e-coo dina ed by wo N a oms ( om he N-ligands), wo µ2-b idging hyd ides and
a e minal hyd ide. The aminopy idina o ligand s abilized compound is uns able and
in amolecula ligand edis ibu ion eac ion leading o monome ic [(PyAp)2AlH] was obse ed
e en a oom empe a u e. The o ma ion p oceeded (mos likely) ia AlH3 o ma ion and i s
decomposi ion o Al and H2. The guanidina o ligand s abilized complex was ound o be mo e
s able and no ligand ans e was obse ed up o 50°C. Fu he mo e, he eac ion o (2R,6S,Z)-
N,N'-bis(2,6-diisop opylphenyl)-2,6-dime hylpipe idine-1-ca boximidamide (MPipGuH) wi h
LiAlH4 was examined. A a e example o a σ-alane li hium complex, namely [(MPipGu)(H)2Al(µ-
H)Li( h )3], was syn hesized in 81 % yield.
Figu e 3.3. C ys al s uc u e o he σ-alane li hium complex [(MPipGu)(H)2Al(µ-H)Li( h )3].
In his compound, he aluminum cen e was i e-coo dina ed. The guanidina o ligand
was bound in a N,N’-dihap o-chela ing mode. Two e minal hyd ides and one b idging hyd ide o
a THF s abilized li hium a om accomplished he coo dina ion sphe e a ound he aluminum a om.
This complex could be a sui able p ecu so o syn hesize o he (example gi en) σ-alane
3. O e iew o Thesis Resul s
16
ansi ion me al o σ-alane lan hanoid complexes. Based on he knowledge, ha he guanidina o
ligand s abilized aluminum dialykls we e no able o unde go hyd ogenolysis o a o d he
co esponding hyd ide compounds, examina ions o g oup 3 me als we e ca ied ou . Chap e 6
deals wi h he syn hesis and s uc u e o a inuclea y ium polyhyd ide compound s abilized by
a guanidina o ligand. The syn hesis and s uc u al de e mina ion o he i s a e ea h“(LnH2)3“
polyhyd ide s abilized by a guanidina o ligand was achie ed. An y ium alkyl complex was
hough o as a p omising s a ing ma e ial and i s beha io o hyd ogenolysis using H2 was
examined. The eac ion o equimola amoun s o y ium ialkyl complex ([YR3( h )2]) (R =
CH2Si(CH3)3, h = e ahyd o u an) wi h he guanidine N,N'-bis(2,6-diisop opylphenyl)pipe idine-
1-ca boximidamide (PipGuH) ga e he esul ing guanidina o ligand s abilized y ium dialkyl
complex ([PipGu)YR2( h )]. This complex ea u es a N,N’-dihap o-guanidina o ligand, wo alkyl
moie ies and one THF molecule coo dina ed o he Y a om. In con as o he aluminum dialkyl
compounds, hyd ogenolysis o his p ecu so wi h H2 (2 ba ) yielded clean o ma ion o he
co esponding guanidina o ligand s abilized inuclea y ium hexahyd ide clus e compound
[{(PipGu)YH2}3( h )2].
Figu e 3.4. C ys al s uc u e o he clus e co e uni o [{(PipGu)YH2}3( h )2] (guanidina o ligands only shown as NCN
moie ies o cla i y).
The isola ed yield was 96 %. Single c ys al X-Ray s uc u e analysis e ealed a iangle
de ined by he h ee y ium a oms. Each y ium a om ca ied a guanidina o ligand in he same
N,N’-dihap o-chela ing mode like in he p ecu so dialkyl complex, as was e ealed by XRD
analysis. Mo eo e , coo dina ed THF molecules o wo o he h ee y ium a oms we e ound.
Highly dynamic beha iou o he hyd ido and he guanidina o ligands was obse ed by a iable
empe a u e 1H NMR spec oscopy. Lan hanoid polyhyd ide clus e possess a ious, in e es ing
s uc u al mo i s and, despi e cyclopen adienyl ligand based compounds, a e small in numbe .
Mo eo e , a b oad a ie y o applica ions a e known. This ype o compound was hough o as
4. The Ligand-Based Quin uple Bond-Sho ening Concep and Some o I s Limi a ions
23
Scheme 1. The ole o he s abilizing ligand on he me al-me al dis ance in complexes ha ing a ( o mal) quin uple
bond. The subs i uen s on op ( ed) al e he N-C-N angle (blue) and comp ess he me al-me al mul iple bond.
We epo he e he esul s o a sys ema ic sea ch o he sho es me al-me al
(quin uple) bond. The inally ob ained dis ance is 1.7056(12) Å. Fu he mo e, we poin ou a
a ew limi a ions o he abo e in oduced ligand based me al-me al bond sho ening concep ,
he main one being he o ma ion o a di e en coo dina ion isome , an unsuppo ed C (I)
dime wi h a signi ican ly lowe bond o de . Quin uple bonding has gained a lo o a en ion
meanwhile. The di-me allic (ch omium o molybdenum) pla o m is well sui ed o ac i a e
small molecules.[15]
4.2 Resul s and Discussion
The hypo hesis we de eloped om he s a e o he a in making ul a-sho
ch omium-ch omium quin uple bonds basically means he C -C dis ance is de e mined by
he subs i uen R linked o he cen al ca bon a om o he guanidina o (o amidina o) ligand
(Scheme 2).
Scheme 2. Syn hesis o he Al-complexes 5-8.

4. The Ligand-Based Quin uple Bond-Sho ening Concep and Some o I s Limi a ions
24
In o de o ind he guanidina e ligand o ming he sho es C -C quin uple bond he
dependence o he ele an N-C-N angle in he guanidina e ligand om he in oduced
subs i uen R (Scheme 2) was in es iga ed.
Aluminum dialkyls we e expec ed o be well sui ed o such a s udy. The e ahed al
coo dina ion a oids in e e ence wi h he emaining ligands and he smoo h syn hesis ia
alkane elimina ion om comme cially a ailable ialkyls allows o an easy access. The
aluminum guanidina es 5-8 (Scheme 2, Figu e 1) we e syn hesized and cha ac e ized ia X-
ay c ys al s uc u e analysis. We obse ed ha inc easing he s e ic demand on he back
bone om pipi idine o diisop opylamine dec eases he NCN bond angle om 109.8(3) in 5 o
107.39(15) in 8 (Figu e 1).[16] Thus, he ligands 3 and 4 should gi e C complexes wi h e en
sho e me al-me al bond dis ances han 2. The C -C complex s abilized by 2 is ea u ing he
sho es me al-me al bond [1.7293 (12) Å] obse ed in a s able molecule ye .[13b]
Figu e 1.Molecula s uc u e o 7 wi h he hyd ogen a oms omi ed o cla i y and he c ucial N-C-N angle o all
s uc u ally in es iga ed Al complexes (R = 2,6-diisop opylphenyl).Selec ed bond leng hs [Å] and angles [°]: Al1-
N2 1.9245(13), Al1-N1 1.9318(13), Al1-C1 1.958(2), Al1-C2 1.9609(19); N2-C5-N1 107.68(12), N2-Al1-N1
69.09(5), N2-Al1-C1 113.78(7), N1-Al1-C1 120.33(8), N2-Al1-C2 118.70(7), N1-Al1-C2 113.44(7), C1-Al1-C2
114.32(9).
The eac ions o he li hium guanidina es, Li[(2,6-dime hylpipi idine)C(NA )2] and
Li[(diisop opylamine)C(NA )2][17] made om 3 and 4, wi h C Cl2 in THF a o ded, a e
emo al o he sol en and subsequen ex ac ion wi h e he , he co esponding C (II) a e-
complexes 9 and 10, espec i ely as blue c ys alline ma e ials in good yields (Scheme 4).
4. The Ligand-Based Quin uple Bond-Sho ening Concep and Some o I s Limi a ions
25
Scheme 4. Syn hesis o 9 and 10.
The 1H NMR spec a showed only b oad signals due o he p esence o pa amagne ic
C (II) ions. Bo h complexes we e s uc u ally in es iga ed by X- ay c ys al s uc u e analysis.
The obse ed s uc u al mo i has been ecen ly epo ed o dike imina e ligands.[18] The
molecula s uc u e o 9 is shown in Figu e 2. I s magne ic momen s (μB) was de e mined o
be 4.54. F om he ini ially selec ed guanidines 3 and 4, ligand p ecu so 4 ca ies he bulkies
subs i uen and o he co esponding Al complex 8 he smalles N-C-N angle was obse ed
(Figu e 1).
Figu e 2. Molecula s uc u e o 9 [ORTEP ep esen a ion (on he 50 % p obabili y le el) o all non ca bon
a oms); Hyd ogen a oms ha e been omi ed o cla i y. Selec ed bond leng hs [Å] and angles [°]: C1-N1 1.348(2),
C1-N2 1.352(3), C1-N3 1.375(3), Li1-O1 1.936(4), Li1-O2 1.941(4), Li1-Cl1 2.347(4), Li1-Cl2 2.361(4), Li1-C 1
3.209(4), N1-C 1 2.0527(16), N2-C 1 2.0455(16), C 1-Cl2 2.3492(6), C 1-Cl1 2.3691(6); N1-C1-N2 109.73(16),
N1-C1-N3 126.79(17), N2-C1-N3 123.48(17), N2-C 1-N1 65.19(6), N2-C 1-Cl2 99.46(5), N1-C 1-Cl2 164.62(5),
N1-C 1-Cl1 101.51(5), Cl2-C 1-Cl1 93.86(2).
4. The Ligand-Based Quin uple Bond-Sho ening Concep and Some o I s Limi a ions
26
Thus, we became in e es ed o use 10, which is s abilized by dep o ona ed 4. The
educ ion o 10 wi h KC8 and wo k up in hexane led o a monome ic C 0 complex (compound
11, Scheme 5), in which he cen al C a om is sandwiched be ween wo a ene uni s o wo
guanidina e ligands (Figu e 3).
Scheme 5. Syn hesis o he C complex 11.
No only he η6-coo dina ion o he a ene uni is limi ed o he b idging C , bu he
same a ene uni also coo dina es one K in he same ashion. Fu he mo e, he guanidina e
ligands in 11 a e ac ing as an amide coo dina ing he K a om h ough N1.
Figu e 3. Molecula s uc u e o 11; Hyd ogen a oms ha e been omi ed o cla i y. Selec ed bond leng hs [Å] and
angles [°]:C5-N2 1.310(5), C5-N1 1.359(5), C5-N3 1.424(6), N1-K1 2.688(4), C 1–A cen oid 1.667, K1–A
cen oid 2.798, O1-K1 2.682(4), O2-K1 2.748(4); N2-C5-N1 122.9(4), N2-C5-N3 117.3(4), N1-C5-N3 119.8(4),
C5-N1-K1 129.6(3), O1-K1-N1 119.59(13), O1-K1-O2 82.70(13), N1-K1-O2 139.72(13).
4. The Ligand-Based Quin uple Bond-Sho ening Concep and Some o I s Limi a ions
27
The K a oms a e u he coo dina ed by wo h molecules. The cen al s uc u al mo i
esembles he classic bis(benzene)ch omium s uc u e.[19] Since he educ ion o 10 leads o
an o e - educed p oduc , we epea ed he eac ion mo e han i e imes also wi h a ied
amoun o po assium g aphi e. The esul s we e simila . We ob ained 11 and le o e s a ing
ma e ial (10) wi h lowe amoun s o he educing agen . F om hese s udies, we concluded
ha he s e ic bulk o he subs i uen in he backbone o 5 is al eady oo la ge o s abilize a
complex ha ing a quin uple bond and con inued wi h a emp s based on 4 (o he dichlo ide
9). Reduc ion o 9 wi h KC8 in THF esul ed in a sudden colo change om oyal blue o
o ange ed (Scheme 6). A e wo k up, 12 was isola ed as pu ple needles a oom
empe a u e. The c ys al s uc u e o 12 e eals a compound whe e he wo guanidina e
ligands do no ac as b idging ligands. They coo dina e o each C a om in a chela ing
ashion gi ing ise o an unsuppo ed C -C -bond. The C -C bond axis is collinea o he C2
axis o NCN moie y o he guanidina e ligand. A C -C bond leng h o 2.652(2) Å is obse ed
o 12.
Scheme 6. Syn hesis o 12 and 13.
The molecula s uc u e o 12 is shown in Figu e 4. The conjuga ed NCN moie y
shows e y simila C-N dis ances [C1-N2 1.360(7), C1-N3 1.363(7), C1-N1 1.374(7) Ǻ].
4. The Ligand-Based Quin uple Bond-Sho ening Concep and Some o I s Limi a ions
28
Figu e 4. Molecula s uc u e o 12. Hyd ogen a oms ha e been omi ed o cla i y. Selec ed bond leng hs [Å] and
angles [°]: C1-N1 1.360(7), C1-N3 1.363(7), C1-N2 1.374(7), N1-C 1 2.036(5), N2-C 1 2.045(5), C 1-C 1
2.652(2); N1-C1-N3 125.5(6), N1-C1-N2 108.9(5), N3-C1-N2 125.5(6), N1-C 1-N2 66.06(18), N1-C 1-C1
32.84(18).
Unsuppo ed ch omium-ch omium bonds a e a e. Pionee ing wo k in his ega d was
epo ed by he Gamba o a g oup.[20] They syn hesized N-ligand s abilized C (II) wi h a a he
weak bond be ween he wo me al a oms. Dime s o C (I) such as hose obse ed he ein a e
di icul o ob ain, because a a ie y o “side eac ions” ha e o be a oided. Complexes o
C (I) become mononuclea i he s abilizing ligand is oo bulky.[11,21] A ene sandwich
complexes can be o med i a oma ic sol en s a e used.[22] The p esence o dini ogen can
lead o N2 complexes.[23] Fu he mo e, b idging o he a yl subs i uen s o he N-ligand has o
be a oided.[24] X- ay c ys al s uc u e analysis, magne ic da a and elec onic s uc u al
calcula ions ( ide in a), IR da a and eac ion wi h CCl4 (no o ma ion o CHCl3)[25] indica e
ha no b idging hyd ides a e p esen in 12. In e es ingly, he second and hi d c op o
c ys alliza ion du ing he syn hesis o 12 did no a o d needles bu o ange ed pla es. The X-
ay s uc u al analysis e ealed a b idged homobime allic compound (13) wi h an
excep ionally sho me al-me al dis ance o 1.7056 (12) Å (Figu e 5). A second c ys al ga e
ise o a s uc u e wi h a C -C dis ance o 1.7061(9) Å. I is he sho es C -C dis ance as
well as he sho es me al-me al bond epo ed o a s able compound ye . A dis ance
app oaching 1.70 Å is in e es ing in a ew ega ds. Fo ins ance, he ch omium-ch omium
bond leng h o ansien C 2 molecule which can be gene a ed by lase -e apo a ion o he
me al and ia lash pho olysis o C (CO)6 is in he same dis ance ange.[26,27] This compound
has a o mal sex uple bond. Fu he mo e, a simila dis ance as o he me al-me al bond in
13 was ound ecen ly o he longes alkane C-C bond[28] [1.704 (4) Å]. This essen ially
means a me al-me al bond and a C-C bond o an alkane can be o simila leng h. The C -N

4. The Ligand-Based Quin uple Bond-Sho ening Concep and Some o I s Limi a ions
29
bond leng hs [1.992(4), 1.993(4), 2.008(4) and 2.011(4) Å] a e compa able o he ones in he
al eady known quin uply bonded ch omium complexes bu sho e han C -N bond dis ances
[2.036(5) and 2.045(5) Å] obse ed o 12.[7,9] The C-N bond dis ances [1.390(6) Ǻ] o he
non-coo dina ing ni ogen a e sligh ly longe han he C-N bond dis ances o ch omium
coo dina ed ni ogen a oms [1.346(6) and 1.336(6) Å].
Figu e 5. Molecula s uc u e o 13. Hyd ogen a oms and one hexane molecule ha e been omi ed o cla i y.
Selec ed bond leng hs [Å] and angles [°]: C1-N2 1.345(6), C1-N1 1.363(6), C1-N3 1.390(6), C13-N5 1.336(6),
C13-N4 1.346(6), C13-N6 1.390(6), N1-C 2 1.992(4), N2-C 1 1.993(4), N4-C 2 2.008(4), N5-C 1 2.011(4), C 1-
C 2 1.7056(12); N2-C1-N1 112.1(4), N2-C1-N3 124.1(4), N1-C1-N3 123.8(4), C 2-C 1-N2 98.27(12), N2-C 1-N5
164.29(17), C 1-C 2-N1 97.26(12), N1-C 2-N4 165.17(17).
In e es ingly, pa allel o ou in es iga ion he Jones g oup syn hesized and
cha ac e ized an i on(I) high-spin complex based on 3 wi h a e y sho Fe-Fe bond
[2.1270(7) Å] ha displays signi ican mul iple-bond cha ac e .[29]
The oom empe a u e magne ic momen o 12 is µB 4.66 which is highe han he
heo e ically expec ed alue o wo S = 2/2 ch omium cen e s ( heo e ical alue o
µB = 4.00), bu lowe han he heo e ical alue o wo S = 3/2 ch omium cen e s ( heo e ical
alue o µB =5.48). This is in good ag eemen wi h a C -C bond wi h an e ec i e bond o de
o 1.25 ( ide in a), whe e wo o he i e elec ons a e in ol ed in me al-me al bond
o ma ion. Upon cooling a con inuous dec ease o he magne ic momen down o µB 0.58
was obse ed. This beha io is bes explained wi h an i e omagne ic in e ac ions be ween
he emaining unpai ed elec ons o he wo ch omium cen e s. The expe imen al da a we e
i assuming wo an i e omagne ically coupled S = 3/2 cen e s wi h H = -JS1S2. The ob ained
coupling cons an J = -62 (1) cm-1 (g = 2, TIP = 0.0013(1) cm3·mol-1) is indica i e o s ong
4. The Ligand-Based Quin uple Bond-Sho ening Concep and Some o I s Limi a ions
30
an i e omagne ic in e ac ions be ween he wo ch omium cen e s. The oom empe a u e
magne ic momen o 13 is µB 2.27 which is indica i e o an S = 0 g ound s a e o he
dinuclea ch omium complex wi h a pa amagne ic impu i y (Ch omium (I) wi h S = 5/2). This
alue does no change signi ican ly upon cooling. The expe imen al da a o 13 we e i
assuming an S = 0 g ound s a e and a empe a u e independen pa amagne ism TIP due o
Zeeman pe u ba ion. The bes i o compound 13 was ound wi h a pa amagne ic impu i y
PI = 5.0 % pe C (S = 5/2) and TIP = 787·10-6 cm3·mol-1. Impu i ies in his %- ange a e no
unusual o he e y eac i e quin uple bonds.[8,15a] In addi ion, he ein, impu i ies o 12 may
play a ole.
Figu e 6.Ac i e o bi als o s uc u e 12 and hei occupa ion numbe s in he g ound s a e.
Finally, mul icon igu a ional quan um chemical calcula ions using he
CASSCF/CASPT2 me hod[30] we e pe o med o examine he elec onic s uc u e o hese
wo coexis ing C 2-guanidina e compounds and in pa icula , he unique bonding o he
unsuppo ed C 2 uni in 12 and compa ed i o he bonding in 13. Va ious dich omium
sys ems, analogues o 13 a e known o ea u e a quin uple me al-me al bond, despi e he
di e en ligands o oxida ion s a e o he C a om. The me al-me al bonding is quan i ied in
e ms o e ec i e bond o de (EBO), de ined as (ηb - ηa)/(ηb + ηa), whe e ηb is he occupa ion
numbe o he bonding na u al o bi al and ηa is he occupa ion numbe o he co esponding
an ibonding na u al o bi al. The g ound s a e o 12 has a highly mul icon igu a ional single
na u e, which is p ac ically degene a e (< 2 kcal/mol) wi h he iple and quin e s a es.
Inspec ion o he na u al o bi al occupa ion numbe s (Figu e 6) indica es ha all he 3d
o bi als, excep one /* pai , a e singly occupied, which gi es a mino con ibu ion o he C -
4. The Ligand-Based Quin uple Bond-Sho ening Concep and Some o I s Limi a ions
31
C bond: he EBO alue o he  bond is 0.11, and he co esponding  and  alues a e
0.16 and 0.04, espec i ely. One elec on om each C a om is in ol ed in C -N in e ac ion
wi h he ligands ( hose o bi als a e no included in he comple e ac i e space). In e es ingly,
he s onges bond in he C 2 uni is he  bond o med om he in e ac ion o he 4s o bi als,
wi h an EBO o 0.94. This esul s in a o al bond o de o 1.25 and an elec onic con igu a ion
(C -C )4s2(C -C )3d1(C -C )3d*1(C -C )3d1(C -C )3d*1(C -C )3d2(C -C )3d*2. Thus,
he long 2.65 Å C -C bond in his unsuppo ed C (I) dime bea s a single 4s–4s in e ac ion
wi h he 3d shells an i e omagne ically coupled in o a ne single s a e.
Table 1. E ec i e bond o de o 12 and 13:, ,  con ibu ions and o al EBO alues. C 2-
guanidina e compound[13b] is gi en o compa ison.
EBO
12
13
C 2-guanidina e[31e]

1.05
0.84
0.83

0.16
1.66
1.62

0.04
1.43
1.35
To al bond o de
1.25
3.93
3.80
In con as o 12, he sho C -C bond in 13 is a o mal quin uple bond wi h he C 3d
o bi als o ming he me al-me al mul iple bond, whe eas he pai o C 4s o bi als is di ec ly
in ol ed in he C -N in e ac ion wi h he ligands. The N a oms in e ac wi h he same weigh
wi h he C -C co e as indica ed by he shape o he C -N molecula o bi als (see Figu e 7).
The o al EBO alue o 3.93 (see Table 1) is sligh ly la ge han he alue o 3.80[31e]
compu ed o he C 2-guanidina e sys em[13b] which holds he p e ious eco d o he sho es
C -C bond. Inspec ion o Table 1 indica es ha he sho ening (ca. 0.02 Å) o he me al-
me al bond is accompanied by a sligh inc ease o he s eng h o one o he  bonds.
Analogously o o he dich omium species,[31e,32] he closed-shell con igu a ion
(C -C )3d2(C -C )3d4(C -C )3d4(C -N)4s2 domina es he mul ide e minan al wa e
unc ion wi h a o al weigh o 70 %.
4. The Ligand-Based Quin uple Bond-Sho ening Concep and Some o I s Limi a ions
32
Figu e 7.Ac i e o bi als o s uc u e 13 and hei occupa ion numbe s in he g ound s a e.
The 1H NMR o 13 shows well esol ed single signal se indica i e o a diamagne ic
compound. Complex 12 is a he s able in solu ion and does no show any decomposi ion o
con e sion o 13 as moni o ed by NMR spec oscopy using a C4D8O solu ion.
4.3 Conclusions
In conclusion, we epo on a a ional app oach o he complex ha ing he sho es
me al-me al bond. The key o isola e i , was a s e ically ailo made guanidina e ligand. The
me al-me al dis ance obse ed is o he same leng h as he longes C-C bond in s able
alkanes. The ligand-based quin uple bond sho ening concep has a ew limi a ions. Mos
impo an ly, he o ma ion o coo dina ion isome s in which in e -ligand epulsion is
minimized. I is assumable ha addi ional sho ening is di icul o accomplish since we
eached he end o he s abili y gap.
4.4 Expe imen al Sec ion
Gene al: All manipula ions we e pe o med wi h igo ous exclusion o oxygen and mois u e
in Schlenk- ype glasswa e on a dual mani old Schlenk line o in N2 illed glo e box (mB aun
120-G) wi h a high-capaci y eci cula o (<0.1ppm O2). Sol en s we e d ied by dis illa ion
om sodium wi e / benzophenone. Comme cial C Cl2 (Al a Aeso ) was used as ecei ed.
Compounds 2, 3, 4 and 8 we e p epa ed acco ding o published li e a u e.[16,17a,33] Deu e a ed
sol en s we e ob ained om Camb idge Iso ope Labo a o ies and we e degassed, d ied and
dis illed p io o use. NMR spec a we e eco ded on Va ian 300 MHz and Va ian 400 MHz a
4. The Ligand-Based Quin uple Bond-Sho ening Concep and Some o I s Limi a ions
39
2009, 471, 1–10; e) G. La Macchia, G. Li Manni, T. K. Todo o a, M. B ynda, F.
Aquilan e, B. O. Roos, L. Gaglia di, Ino g. Chem. 2010, 49, 5216–5222.
[32] G. Li Manni, A. Dzubak, A. Mulla, D. W. B ogden, J. F. Be y, L. Gaglia di, Chem. Eu .
J. 2012, 18, 1737–1749.
[33] S. Ge, A. Mee sma, B. Hessen, O ganome allics 2008, 27, 3131–3135.
[34] A. Al oma e, M. C. Bu la, M. Camalli, G. L. Casca ano, C. Giaco azzo, A. Guaglia di,
A. G. G. Moli e ni, G. Polido i and R. Spagna, J. Appl. C ys . 1999, 32, 115–119.
[35] SHELX97 P og ams o C ys al S uc u e Analysis (Release 97-2). G. M. Sheld ick,
Ins i u ü Ano ganische Chemie de Uni e si ä , Tammans asse 4, D-3400
Gö ingen, Ge many, 1998.
[36] L. J. Fa ugia, J. Appl. C ys . 1999, 32, 837–838.

4. The Ligand-Based Quin uple Bond-Sho ening Concep and Some o I s Limi a ions
40
4.7 Suppo ing In o ma ion
X- ay c ys allog aphic da a including ables, de ails o he magne ic and compu a ional s udy
Figu e S1. Molecula s uc u e o 5 [ORTEP ep esen a ion (on he 50 % p obabili y le el) o all non ca bon
a oms]; Hyd ogen a oms ha e been omi ed o cla i y.
Figu e S2. Molecula s uc u e o 6 [ORTEP ep esen a ion (on he 50 % p obabili y le el) o all non ca bon
a oms]; Hyd ogen a oms ha e been omi ed o cla i y.
Figu e S3. Molecula s uc u e o 10 [ORTEP ep esen a ion (on he 50 % p obabili y le el) o all non ca bon
a oms]; Hyd ogen a oms ha e been omi ed o cla i y.
4. The Ligand-Based Quin uple Bond-Sho ening Concep and Some o I s Limi a ions
41
Table S1. C ys al da a o Al compounds 5, 6 and 7.
compound
5
6
7
Empi ical o mula
C32H50AlN3
C29H46AlN3
C34H54AlN3
Fo mula weigh
503.73
463.67
531.78
c ys al sys em
Hexagonal
Hexagonal
Monoclinic
space g oup
P3(2)21
P3(2)21
P2(1)/c
a [Å]
14.9090(7)
14.4200(6)
9.4030(5)
b [Å]
14.9090(7)
14.4200(6)
31.9350(17)
c [Å]
12.2510(6)
12.2130(5)
11.2800(6)
α [deg]
 [deg]
106.059(4)
γ [deg]
V, [Å3]
2358.30(19)
2199.29(16)
3255.0(3)
c ys al size, [mm3]
0.41 x 0.36 x 0.35
0.34 × 0.33 × 0.29
0.67 x 0.55 x 0.48
calcd, [g cm-3]
1.064
1.050
1.085
µ, [mm-1] (Mo K)
0.087
0.089
0.088
T, [K]
133(2)
133(2)
133(2)
 ange, [deg]
1.58- 25.69
1.63- 25.60
1.28- 25.80
no. o e lec ions unique
2991
2769
6171
no. o e lec ions obs. [I > 2 ( I )]
2394
2580
5293
no. o pa ame e s
187
157
343
wR2 (all da a )
0.1083
0.0785
0.1226
R alue [I>2 (I)]
0.0463
0.0352
0.0477
4. The Ligand-Based Quin uple Bond-Sho ening Concep and Some o I s Limi a ions
42
Table S2. C ys al da a o C compounds 9, 10, 11, 12 and 13.
compound
9
10
11
12
13
Empi ical o mula
C40H64Cl2C LiN3O2
C39H64Cl2C LiN3O2
C78H128C K2N6O4
C64H96C 2N6
C70H108C 2N6
Fo mula weigh
748.78
736.77
1344.06
526.73
1137.62
c ys al sys em
T iclinic
Monoclinic
Monoclinic
T iclinic
T iclinic
space g oup
P-1
C2/c
P2(1)/n
P-1
P-1
a [Å]
11.2860(6)
16.0290(5)
10.6720(6)
10.8060(8)
12.6160(5)
b [Å]
13.7030(6)
16.4480(5)
18.8650(10)
10.9290(9)
15.1330(6)
c [Å]
14.689(8)
16.8070(7)
20.0340(10)
15.8220(12)
19.4170(7)
α [deg]
102.318(4)
90.514(6)
112.679(3)
 [deg]
94.489(4)
108.140(3)
104.381(4)
70.900(6)
95.143(3)
γ [deg]
107.100(4)
69.395(6)
98.334(3)
V, [Å3]
2096.95(18)
4210.8(3)
3907.0(4)
1601.6(2)
3341.0(2)
c ys al size, [mm3]
0.36 x 0.32 x 0.24
0.23 x 0.21 x 0.18
0.42 x 0.27 x 0.07
0.31 x 0.29 x 0.15
0.21 × 0.20 × 0.12
calcd, [g cm-3]
1.186
1.162
1.142
1.092
1.131
µ, [mm-1] (Mo K)
0.435
0.432
0.302
0.379
0.368
T, [K]
133(2)
133(2)
133(2)
193(2)
133(2)
 ange, [deg]
1.44-25.67
1.82-25.67
1.51-25.67
2.49-25.66
1.15-25.69
no. o e lec ions unique
7899
3961
7380
6018
12613
no. o e lec ions obs.
[I > 2 ( I )]
6333
2919
3630
1959
4306
no. o pa ame e s
442
219
424
335
694
wR2 (all da a )
0.1120
0.1025
0.1781
0.1685
0.1419
R alue [I>2 (I)]
0.0418
0.0463
0.0794
0.0718
0.0611
Suscep ibili y measu emen s: Magne ic suscep ibili y measu emen s we e ca ied ou wi h
a Quan um Design MPMS-XL SQUID magne ome e in he ange om 2 o 300 K a 2 T (12)
and 0.5 T (13). The powde ed sample 12 was placed in a gela in capsule, ixed in a non-
magne ic sample holde and measu ed in he RSO mode. The powde ed sample 13 was
placed in a qua z glass holde , ixed in a non-magne ic sample holde and measu ed in he
DC mode. The magne ic da a we e co ec ed o he diamagne ic con ibu ion o he sample
holde and he qua z glass o gela in capsule, espec i ely. The mola suscep ibili y da a
we e co ec ed using he Pascal cons an . The expe imen al da a o 13 we e i assuming an
S = 0 g ound s a e and a empe a u e independen pa amagne ism TIP due o Zeeman
pe u ba ion. The bes i o compound 13 was ound wi h a pa amagne ic impu i y PI = 5.0
% pe C (S = 5/2) and TIP = 787·10-6 cm3·mol-1.
4. The Ligand-Based Quin uple Bond-Sho ening Concep and Some o I s Limi a ions
43
Figu e S4. Tempe a u e dependence o he MT p oduc o 12. The solid line ep esen s he i wi h H = -JS1S2 (S
= 3/2), J = -62 (1) cm-1 and TIP = 0.0013(1) cm3·mol-1 assuming g = 2.
Figu e S5. A) Tempe a u e dependence o he mola suscep ibili y o 13 (open ci cles). The solid line ep oduces
he bes i wi h he pa ame e s PI = 5.0 % pe C (S = 5/2) and TIP = 787·10-6 cm3·mol-1. B) Tempe a u e
dependence o he MT p oduc o 13.
050 100 150 200 250 300
0
1
2
3
molT[cm3Kmol-1]
T [K]
050 100 150 200 250 300
0.0
0.5
1.0
MT[cm3Kmol-1]
T [K]
a) b)
050 100 150 200 250 300
0,00
0,01
0,02
0,03
0,04
0,05
M[cm3mol-1]
T [K]
4. The Ligand-Based Quin uple Bond-Sho ening Concep and Some o I s Limi a ions
44
Figu e S6. The empe a u e dependence o he mola magne ic suscep ibili y o 11. The open poin s a e he
obse ed suscep ibili y, he black line ep oduces he bes i wi h he pa ame e s PI = 0.55 % (pe C , S = 3/2 and
Weiss cons an θ = –1 K) and TIP = 26∙10-6 cm3∙mol-1.
Compu a ional de ails: Quan um chemical calcula ions we e pe o med using he mul i-
con igu a ional Comple e Ac i e Space SCF (CASSCF)[1] me hod, ollowed by second-o de
pe u ba ion heo y (CASPT2).[2] Rela i is ic all elec on ANO-RCC basis se s wi h iple-ze a
quali y (ANO-RCC-VTZP) we e used on ch omium and ni ogen[3] and minimal basis se s
(ANO-RCC-MB) on ca bon and hyd ogen.[4] Scala ela i is ic e ec s we e included using he
Douglas-K oll-Hess Hamil onian.[5] The compu a ional cos s a ising om he wo-elec on
in eg als we e d as ically educed by employing he Cholesky decomposi ion (CD)
echnique[6] combined wi h he Local Exchange (LK) sc eening.[9] In he CASSCF ea men ,
he comple e ac i e space con ains en elec ons in wel e ac i e o bi als (10/12). This space
comp ises all 3d and 4s o bi als o ming he C -C bond, namely one 4s, one 3d, wo 3d
and wo 3d bonding and he co esponding an ibonding o bi als. In he subsequen CASPT2
calcula ions, o bi als up o and including he 2p o C and 1s o C and N we e kep ozen.
The F ozen Na u al O bi al app oach wi h 70% o he i ual o bi als aken in o accoun was
applied o CASPT2 (FNO-CASPT2) o sa ing disk equi emen s and educing compu a ional
cos s.[10] Ci symme y was imposed. The C -C bonding is quan i ied in e ms o e ec i e
bond o de (EBO), de ined as (ηb - ηa)/(ηb+ηa), whe e ηb is he occupa ion numbe o he
bonding na u al o bi al andηa is he occupa ion numbe o he co esponding an ibonding
na u al o bi al. The CASSCF/CASPT2 app oach has p o en o be e y success ul in he
s udies o me al-me al bonded compounds.[11,14] All calcula ions we e pe o med wi h he
MOLCAS 7.4 package.[15]

4. The Ligand-Based Quin uple Bond-Sho ening Concep and Some o I s Limi a ions
45
4.8 Re e ences
[1] B.O. Roos, P. R. Taylo , P. E. M. Siegbahn, Chem. Phys. 1980, 48, 157-173.
[2] K. Ande sson, P.-A. Malmq is , B.O. Roos, J. Chem. Phys. 1992, 96, 1218-1226.
[3] B. O. Roos, R. Lindh, P. A. Malmq is , V. Ve yazo , P. O. Widma k, J. Phys. Chem. A
2005, 108, 2851-2858.
[4] P. O. Widma k, P. A. Malmq is , B. O.Roos, Theo . Chim. Ac a 1990, 77, 291-306.
[5] B. A. Hess, Phys. Re . A 1986, 33, 3742-3748.
[6] F. Aquilan e, P.A. Malmq is , T. B. Pede sen, A. Gosh and B. O. Roos, J. Chem.
Theo y Comp. 2008, 4, 694-702.
[7] F. Aquilan e, T. B. Pede sen, R. Lindh, B. O. Roos, A. S. de Me as, H. Koch, J.
Chem. Phys. 2008, 129, 024113.
[8] F. Aquilan e, L. Gaglia di, T. B. Pede sen, R.Lind , J. Chem. Phys. 2009, 130,
154107.
[9] F. Aquilan e, T. B. Pede sen, R. Lindh, J. Chem. Phys. 2007, 126, 194106.
[10] F. Aquilan e, T. K. Todo o a, L. Gaglia di, T. B. Pede sen, B. O. Roos, J. Chem.
Phys. 2009, 131, 034113.
[11] M. B ynda, L. Gaglia di, B. O. Roos, Chem. Phys. Le . 2009, 471, 1-10.
[12] G. La Macchia, L. Gaglia di, P. P. Powe , M. B ynda, J. Am. Chem. Soc. 2008, 130,
5104-5114.
[13] L. Gaglia di, B. O. Roos, Ino g. Chem. 2003, 42, 1599-1603.
[14] B. O. Roos, A. Bo in, L. Gaglia di, Angew. Chem. In . Ed. 2007, 46, 1469-1472.
[15] G. Ka ls öm, R. Lindh, P. A. Malmq is , B.O. Roos, U. Ryde, V. Ve yazo , P. O.
Widma k, M. Cossi, B. Schimmelp ennig, P. Neog ady, L. Seijo, Compu . Ma e . Sci.
2003, 28, 222-239.
5. Syn hesis and S uc u e o Aminopy idina o and Guanidina o Ligand S abilized Al-H Complexes
46
5 Syn hesis and S uc u e o Aminopy idina o and Guanidina o
Ligand S abilized Al-H Complexes
Tobias Baue ,[a] Win ied P. K e schme ,[a] Muhammad Ha eez[a,b], and Rhe Kempe*[a]
[a] T. Baue , D . W. P. K e schme , D . M. Ha eez, P o . D . R. Kempe, Leh s uhl Ano ganische
Chemie II, Uni e si ä Bay eu h, Uni e si ä ss asse 30, NW I, 95440 Bay eu h (Ge many), Fax:
(+49) 921552157, E-mail: kempe@uni-bay eu h.de
[b] D . M. Ha eez, Depa men o Chemis y, Uni e si y o Azad Jammu and Kashmi ,
Muza a abad 13100, Azad Kashmi ,(Pakis an).
To be submi ed.
Keywo ds: Alanes•σ-alanes • N-ligands
Abs ac : The eac ion o he aminopy idine N-(2,6-diisop opylphenyl)-6-(py olidin-1-yl)py idin-
2-amine (PyApH) and he guanidine N,N'-bis(2,6-diisop opylphenyl)pipe idine-1-
ca boximidamide (PipGuH) wi h ( eshly p epa ed) AlH3 was in es iga ed. Fo bo h N-ligands
he o ma ion o a dime ic, double hyd ogen b idged aluminum dihyd ide complex is obse ed.
The aminopy idina e is uns able and an in amolecula ligand edis ibu ion eac ion leading o
monome ic [(PyAp)2AlH] is obse ed. The o ma ion p oceeds (mos likely) ia AlH3 o ma ion
and i s decomposi ion o Al and H2. The guanidina e was ound o be mo e s able and no ligand
ans e was obse ed up o 50°C. Fu he mo e, he eac ion o (2R,6S,Z)-N,N'-bis(2,6-
diisop opylphenyl)-2,6-dime hylpipe idine-1-ca boximidamide (MPipGuH) wi h LiAlH4 was
examined. The σ-alane li hium complex [(MPipGu)(H)2Al(µ-H)Li( h )3] was o med in 81 % yield.
I could be a sui able educ o syn hesize o he ( o ins ance) σ-alane ansi ion me al
complexes.
5.1 In oduc ion
Aluminum is he hi d mos abundan elemen and he mos abundan me al in he
ea h`s c us . I `s hyd ide, alane, is p ominen ly used in o ganic syn hesis as educing agen .[1]
Mo eo e , i can be used o educe me al complexes.[2] Fu he mo e, alanes ha e in e es ing
applica ions in hyd oalumina ion eac ions[3], as p ecu so s in me al o ganic chemical apou
5. Syn hesis and S uc u e o Aminopy idina o and Guanidina o Ligand S abilized Al-H Complexes
47
deposi ion,[4] and as hyd ogen s o age ma e ials.[5,6] In addi ion, ansi ion me al σ-alane
complexes a e o g ea in e es .[7] No el alanes could ex en o imp o e hese po en ial
applica ions.
He ein we epo on syn hesis and s uc u e o aminopy idina o and guanidina o ligand
s abilized Al-H complexes. All complexes p esen ed he ein we e cha ac e ized ia single c ys al
X- ay s uc u e analysis (XRD). Un il now, only a small numbe o s uc u ally ully cha ac e ized
amidina o and guanidina o ligand s abilized alanes a e known. Recen ly, a guanidina o ligand
s abilized adduc o dialane (Al2H4) wi h an aluminum-aluminum bond was epo ed.[8]
5.2 Resul s and Discussion
Aminopy idina o ligands (Ap, Scheme 1, le )[9,10,11] a e biden a e, monoanionic ligands
ela ed o guanidina o ligands (Gu, Scheme 1, igh )[12]. Bo h ligand classes a e able o s abilize
a b oad a ie y o me al ions.[12,13]
N NR R' N
RN
N
R'
R'' R'''
Scheme 1. Aminopy idina o ligands and he ela ed guanidina o ligands (R, R’, R’’, R’’’ = a yl, alkyl o silyl
subs i uen s).
As one can see, bo h ligand amilies can be ine- uned wi h ega d o hei elec on
dona ing abili ies and he s e ic bulk ia he subs i uen s (R and R’ in he Ap sys em, R, R’, R’’
and R’’’ in he Gu sys em). Fi s ly, we s a ed wi h s udies on Ap ligand s abilized alanes. We
did chose N-(2,6-diisop opylphenyl)-6-(py olidin-1-yl)py idin-2-amine (PyApH, 1a) due o i s
elec on dona ing abili y.[14] T ea men o one equi alen o he aminopy idine 1a in oluene wi h
one equi alen o in si u p epa ed AlH3 in a 1:2 mix u e o e he / oluene lead o he o ma ion o
he dime ic aluminium hyd ide species [(PyApAlH2)2] 2a in 54% yield (Scheme 3). C ys als
sui able o XRD analysis could be g own by s o age o a concen a ed oluene solu ion o 2a
a -40°C. The molecula s uc u e o compound 2a is shown in Figu e 1.Expe imen al de ails o
he XRD s udies can be ound in Table 1. NMR s udies o compound 2a e ealed, as expec ed,
a single se o p o on esonances o he equi alen Ap ligands and a e y b oad single a

=
5.00 ppm o he ou aluminium hyd ides. This indica es luxional, dynamic beha iou in
solu ion.
5. Syn hesis and S uc u e o Aminopy idina o and Guanidina o Ligand S abilized Al-H Complexes
48
Scheme 3. Syn hesis o he dime ic compound 2a.
Two double s a

= 5.07 and 5.19 ppm belonging o he a oma ic p o ons in he py idine
ing (3 and 5 posi ion) a e qui e up ield o a oma ic p o ons. This can be explained by he
inc eased elec on dona ing abili y o he PyAp ligand due o he py olidinyl moie y. Ano he
con i ma ion o he inc eased elec on dona ing abili y o PyAp is ound in he c ys al s uc u e
o 2a. The sum o all angles a ound N3 is 359.8°, indica ing a nea ly pe ec plana sp2
hyb idized N a om. The o sion angle by which N3 is shi ed ou o he plane is only 2.7°.
Mo eo e , he dis ance be ween N3 and C5 is 1.3475(10) Å, lying be ween a N-Csp2 double
bond (1.28 Å in a e age) and a N-Csp2 single bond (1.48 Å in a e age).[15] The amido N-Al
dis ance o 1.8742(6) Å and he py idine N a om o Al dis ance o 2.0358(7) Å indica e ha he
anionic cha ge o he Ap ligand is localized a he amido N a om. The aluminum cen e s a e
i e-coo dina ed by wo N a oms ( om he Ap ligand), a e minal and wo b idging hyd ides.
Figu e 1. Molecula s uc u e o compound 2a wi h 50% he mal ellipsoids. Ca bon a oms a e displayed as sphe es,
Hyd ogen a oms, excep o he hyd ides, a e omi ed o cla i y. Selec ed bond leng hs [Å] and bond angles [°]:Al1–
H1 1.479(9), Al1–H2 1.624(9), C5–N3 1.3475(10), C5–N2 1.3498(10), N1–Al1 1.8742(6), N2–Al1 2.0358(7), N1–C1–
N2 107.53(6).
5. Syn hesis and S uc u e o Aminopy idina o and Guanidina o Ligand S abilized Al-H Complexes
55
6.8 Hz, CH(CH3)2), 2.63 (m, 4H, CH2), 3.02 (m, 4H, CH2), 3.59 (sep ., 2H, CH(CH3)2), 3.65
(sep ., 2H, CH(CH3)2), 5.21 (d, 2H, JHH = 7.7 Hz, m-C5N1H3), 5.27 (d, 2H, JHH = 7.7 Hz, m-
C5N1H3), 6.94 ( , JHH = 8.0 Hz, 2H, p- C5N1H3), 7.10-7.19 (m, 6H, a om. CH). 13C NMR (100
MHz, C6D6, 298 K): δ = 22.09, 24.65, 25.04, 25.17, 27.22, 28.41, 28.94, 45.13, 46.94, 91.85,
93.91, 123.27, 124.30, 125.66, 127.70, 140.27, 140.87, 146.67, 147.53, 154.86, 166.71.
Syn hesis o [{(PipGu)Al(H)(µ-H)}2] (2b):
To a eshly p epa ed solu ion o AlH3 in e he (15 mL, 2 mmol) was added a solu ion o PipGuH
(895.4 mg, 2 mmol) in e he (10 mL). The eac ion mix u e was s i ed a 300 pm o e nigh .
Concen a ion o he mix u e o app oxima ely 5 mL, ollowed by hea ing un il he sa u a ed
solu ion s a ed o boil, ga e colo less c ys als sui able o X- ay s uc u e analysis upon s o age
a ambien empe a u e. Yield: 0.828 g (87 %). C60H92Al2N6 (951.38): Calcd. C 75.75, H 9.75, N
8.83; ound. C 75.30, H 9.61, N 8.78; 1H NMR (300 MHz, C6D6, 298 K): δ = 0.83 (m, b ., 12H
CH2), 1.29 (d, 24H, CH(CH3)2), 1.34 (d, 24H, CH(CH3)2), 2.73 (m, 8H, N(CH2)2), 3.68 (sep , 8H,
CH(CH3)2), 4.83 (s, b , 4H Al-H), 7.07 – 7.11 (m, 12H, m-C5H3, p-C5H3). 13C NMR (100 MHz,
C6D6, 298 K): δ = 23.23, 23.49, 24.78, 26.12, 28.47, 47.67, 105.19, 123.88, 139.12, 144.53,
163.67.
Syn hesis o [(MPipGu)(H)2Al(µ-H)Li( h )3](4c):
LiAlH4 (151.8 mg, 4 mmol) was dissol ed in e he (10 mL) a 0° C and MPipGuH (1.902 g, 4
mmol) in e he (10 mL) was added slowly. The eac ion mix u e was allowed o wa m o ambien
empe a u e and was s i ed a 300 pm o e nigh . The sol en was emo ed unde educed
p essu e and he c ude esidue was ex ac ed wi h THF. Concen a ion o he clea solu ion
ga e colo less c ys als a e s o age a 10° C o e nigh . Yield: 2.359 g (81 %). C44H75AlLiN3O3
(728.01): Calcd. C 72.59, H 10.38, N 5.77; ound. C 72.92, H 10.82, N 6.55; 1H NMR (300 MHz,
C6D6, 298 K): δ = 0.77 (d, 6H, JHH = 7.0 Hz, N{CH(CH3)}2),0.86-1.23 (m, 6H, CH2), 1.32 (m, b ,
12H, THF), 1.37 (d, 12H, JHH = 6.8 Hz, CH(CH3)2), 1.41 (d, 12H, JHH = 6.8 Hz, CH(CH3)2), 3.43
(m, 12H, THF),3.6-4.3 (m, b , 3H. Al-H), 3.81 (sep ., 4H, CH(CH3)2), CH(CH3)2), 3.93 (sep ., 2H,
NCH(CH3)), 7.02-7.19 (m, 6H, a om. CH). 13C NMR (100 MHz, C6D6, 298 K): δ = 13.65, 21.37,
23.31, 25.56, 26.94, 28.46, 29.78, 48.43, 123.72, 145.08, 163.40.

5. Syn hesis and S uc u e o Aminopy idina o and Guanidina o Ligand S abilized Al-H Complexes
56
5.5 Re e ences
[1] J. Málek and M. Ce ný, Syn hesis 1972, 217–234.
[2] B. M. Bulyche , Polyhed on 1990, 9, 387–408.
[3] H. Haubens ock, E. L. Eliel, J. Am. Chem. Soc. 1962, 84, 2363–2368.
[4] J. A. Jegie , W. L. Glad el e , Coo d. Chem. Re . 2000, 206–207, 631–650.
[5] a) L. Schlapbach, A. Zü el, Na u e 2001, 414, 353-358; b) E. Da id, J. Ma e . P oc.
Technol. 2005, 162, 169–177; c) U. Ebe le, M. Felde ho , F. Schü h, Angew. Chem.
2009, 121, 6732–6757; Angew. Chem. In . Ed. 2009, 48, 6608–6630, d) S. F. Ma a ,
P og. Solid S a e Chem. 2010, 38, 1-37; e) S. F. Ma a , P og. Solid S a e Chem. 2012,
40, 31–40.
[6] Fo ecen examples see: a) A. Zü el, Ma e . Today 2003, 24–33; b) M. La oche, J.
Phys. Chem. Solids 2004, 65, 517–522; c) W. G ochala, P. P. Edwa ds, Chem. Re .
2004, 104, 1283–1315; d) L. Hou, Renew. Sus ain. Ene gy Re . 2005, 9, 395–408; e) L.
Zhou, Y. Zhou, Y. Sun, In . J. Hyd ogen Ene gy, 2006, 31, 259–264; ) U. Ebe le, G.
A nold, R. V. Helmhol , J. Powe Sou . 2006, 154, 456–460; g) B. Sakin una, F. Lama i-
Da k im, M. Hi sche , In . J. Hyd ogen Ene gy 2007, 32, 1121–1140; h) B. Bogdano ić,
U. Ebe le, M. Felde ho , F. Schü h, Sc ip a Ma . 2007, 56, 813–816; i) S. Ha de , J.
Spielmann, J. In emann, H. Bandmann, Angew. Chem. 2011, 123, 4242–4246; Angew.
Chem. In . Ed. 2011, 50, 4156–4160; h) P. Jochmann, J. P. Da in, T. P. Spaniol, L.
Ma on, J. Okuda, Angew. Chem. 2012, 124, 4528–4531; Angew. Chem. In . Ed. 2012,
51, 4452–4455; j) J. In emann, J. Spielmann, P. Si sch, S. Ha de , Chem. Eu . J. 2013,
DOI: 10.1002/chem.201300684
[7] I. M. Riddles one, S. Edmonds, P. A. Kau man, J. U bano, J. I. Ba es, M. J. Kelly,
A. L. Thompson, R. Taylo , S. Ald idge, J. Am. Chem. Soc. 2012, 134, 2551−2554.
[8] S. J. Bonhady, D. Collis, G. F enking, N. Holzmann, C. Jones, A. S asch, Na . Chem.
2010, 2, 865–869.
[9] Fo e iew a icles on aminopy idina o ligands, see: a) R. Kempe, H. Noss, T. I gang, J.
O ganome . Chem. 2002, 647, 12–20; b) R. Kempe, Eu . J. Ino g. Chem. 2003, 791–
803.
[10] Fo discussions on ligand binding modes, see: S. Deeken, G. Mo z, R. Kempe, Z. Ano g.
Allg. Chem. 2007, 633, 320–325.
[11] Fo de ails on he syn hesis o aminopy idines ia Pd-ca alyzed a yl amina ion ou e,
see: a) S. Wagaw, S. L. Buchwald, J. O g. Chem. 1996, 61, 7240–7241; b) T. Scha eina,
G. Hilleb and, H. Fuh mann, R. Kempe, Eu . J. Ino g. Chem. 2001, 2421–2426.
5. Syn hesis and S uc u e o Aminopy idina o and Guanidina o Ligand S abilized Al-H Complexes
57
[12] Fo e iew a icles on guanidina o ligands and hei gene al applicabili y, see: a) F. T.
Edelmann, Ad . O ganome . Chem. 2008, 57, 183-352; b) C. Jones, Coo d. Chem. Re .
2010, 254, 1273–1289.
[13] Fo examples o he gene al applicabili y o Ap ligands, see: a) G. Gla z, G. Mo z, R.
Kempe, Z. Ano g. Allg. Chem. 2008, 634, 2897–2902. G. Gla z, S. Demeshko, G. Mo z,
R. Kempe, Eu . J. Ino g. Chem. 2009, 1385–1392.
[14] a) M. Ha eez, W. P. K e schme , R. Kempe, Eu . J. Ino g. Chem. 2011, 5512–5522; b)
M. Ha eez, W. P. K e schme , R. Kempe, Z. Ano g. Allg. Chem. 2012, 638, 324–330.
[15] F. H. Allen, O. Kenna d, D. G. Wa son, L. B amme , A. G. O pen, J. Chem. Soc., Pe kin
T ans. 2 1987, S1–S19.
[16] M. L. Cole, C. Jones, P. C. Junk, M. Klo h, A. S asch, Chem. Eu . J. 2005, 11, 4482-
4491.
[17] H.-J. Himmel, Ino g. Chem. 2007, 46, 6585-6593.
[18] F. M. B owe , N. E. Ma zek, P. F. Reigle , H. W. Rinn, C. B. Robe s, D. L. Schmid , J. A.
Sno e , K. Te ada, J. Am. Chem. Soc. 1976, 98, 2450–2453.
[19] a) W. P. K e schme , B. Hessen, A. Noo , N. M. Sco , R. Kempe, J. O ganome . Chem.
2007, 692, 4569–4579; b) C. Dö ing, R. Kempe, Eu . J. Ino g. Chem. 2009, 412–418.
[20] R. Ducha eau, A. Mee sma, J. H. Teuben, Chem. Commun. 1996, 223–224.
[21] S. K. T. Pillai, W. P. K e schme , M. T ebbin, S. Fö s e , R. Kempe, Chem. Eu . J. 2012,
18, 13974–13978.
[22] a) A. Heine, D. S alke, Angew. Chem. 1992, 104, 941–942; Angew. Chem. In . Ed. 1992,
31, 854–855; b) M. G. Ga dine , C. l. Ras on, Coo d. Chem. Re . 1997, 166, 1–34; c) H.
Nö h, A. Schlegel, J. Knizek, I. K ossing, W. Ponikwa , T. Sei e , Chem. Eu . J. 1998, 4,
2191–2203.
[23] A. Noo , T. Baue , T. K. Todo o a, B. Webe , L. Gaglia di, R. Kempe, Chem. Eu . J.
2013, 19, 9825–9832..
[24] G. Jin, C. Jones, P. C. Junk, K.-A. Lippe , R. P. Rose, A. S asch, New J. Chem. 2009,
33, 64–75.
[25] A. Al oma e, M. C. Bu la, M. Camalli, G. L. Casca ano, C. Giaco azzo, A. Guaglia di, A.
G. G. Moli e ni, G. Polido i, R. Spagna, J. Appl. C ys . 1999, 32, 115–119.
[26] G. M. Sheld ick, Ac a C ys . 2008, A64, 112–122.
[27] L. J. Fa ugia, J. Appl. C ys . 1999, 32, 837–838.
6. Syn hesis and S uc u e o a T inuclea Y ium Polyhyd ide Clus e S abilized by a Bulky Guanidina o Ligand
58
6 Syn hesis and S uc u e o a T inuclea Y ium Polyhyd ide
Clus e S abilized by a Bulky Guanidina o Ligand
Tobias Baue [a], and Rhe Kempe*[a]
[a] T. Baue , P o . D . R. Kempe, Leh s uhl Ano ganische Chemie II, Uni e si ä Bay eu h,
Uni e si ä ss asse 30, NW I, 95440 Bay eu h (Ge many), Fax: (+49) 921552157, E-Mail:
kempe@uni-bay eu h.de
To be submi ed.
Keywo ds: Polyhyd ide Clus e Compounds • Ra e Ea hs • X-Ray Di ac ion • Hyd ide
Ligands • N-Ligands
6.1 In oduc ion
Polyhyd ide complexes o he a e ea h (RE) me als (g oup 3 me als and lan hanoid
me als [Ce-Lu]) ha e ascina ed chemis s due o hei eac i i y and s uc u al mo i s.
Fu he mo e, RE (poly)hyd ides a e among he mos eac i e compounds known.[1] Recen ly,
he in e es in RE hyd ides has shi ed om monohyd ide L2LnH complexes[2] o dihyd ide LLnH2
complexes. The dihyd ide complexes end o agg ega e and a y in s uc u e anging om
hexanuclea ,[1e,3a-c] pen anuclea ,[3c] e anuclea ,[3b-j,3o] inuclea [3b,3k-o] o dinuclea complexes.[3 ]
The nuclea i y mainly dependen s om he s e ic bulk o he ancilla y ligand used. An inc ease
in he s e ic demand o he ancilla y ligand seems o lead o a dec ease in nuclea i y.
S uc u ally ully cha ac e ized ( us able de e mina ion o he posi ions o he hyd ogen a oms)
lan hanide polyhyd ide complexes s ill lack in numbe . Un il now, mos ly s e ically demanding
cyclopen adienyl de i a i es,[3d-h,3j] sco piona o [ is(py azolyl)hyd obo a e] ligands,[3a,b]
e aazacycloamido[3l] and aminopy idina o ligands[3m,q] ha e been used o s abilize he “(LnH2)x”
uni .
He ein, we epo on syn hesis and s uc u e o he i s RE (LnH2)3 polyhyd ide s abilized
by a guanidina o ligand.
6. Syn hesis and S uc u e o a T inuclea Y ium Polyhyd ide Clus e S abilized by a Bulky Guanidina o Ligand
59
6.2 Resul s and Discussion
All complexes syn hesized we e cha ac e ized by NMR spec oscopy, elemen al analysis
and single c ys al X- ay s uc u e analysis (XRD). Fi s , we syn hesized he guanidina e y ium
dialkyl complex 1 (Scheme 1). The equimola eac ion o h s abilized y ium ialkyl
(Y(CH2SiMe3)3 h 2) wi h he guanidine (Z)-N,N'-bis(2,6-diisop opylphenyl)pipe idine-1-
ca boximidamide (PipGuH) in n-hexane a o ded clean o ma ion o he guanidina o ligand
s abilized y ium dialkyl complex [PipGuY(CH2SiMe3)2 h ] 1 in 80 % yield (Scheme 1). NMR
in es iga ion o compound 1 showed, as one would expec o a mononuclea complex, a single
se o p o on esonances o he guanidina o ligand, one signal se o he wo alkyl moie ies and
one signal se o he coo dina ed h . The YCH2 esonance (D6-benzene, ) o 1 is ound a δ
= -0.26 ppm wi h a coupling cons an JYH = 3.0 Hz. This is in good compa ison o ela ed NMR
s udies (D6-benzene, ) on guanidina o ligand s abilized y ium dialkyl
[(A NC(NMe2)NA )Y(CH2SiMe3)2 h ][4] (δ = -0.31, JYH = 2.9 Hz), amidina o ligand s abilized
y ium dialkyl [PhC-(NA )2]Y(CH2SiMe3)2 h ][5] (δ = -0.11, JYH = 3 Hz) and aminopy idina o ligand
s abilized y ium dialkyl [(A )6-{(2,4,6- iisop opylphenyl) py idine-2-yl)amido}Y(CH2SiMe3)2 h ][6]
(δ = -0.42 JYH = 3.0 Hz) (A = 2,6-diisop opylphenyl) complexes.
Scheme 1. Syn hesis o 1.
Single c ys als sui able o XRD analysis we e g own om a sa u a ed hexane/ oluene
(1:1 a io) solu ion by slowly cooling o -40° C. The molecula s uc u e o compound 1 is
depic ed in Figu e 1. Compound 1 c ys allizes in he monoclinic spaceg oup P2(1)/n and
ea u es a N,N’-dihap o-guanidina o ligand, wo alkyl moie ies and one h molecule coo dina ed
o he Y a om. The O a om o he h molecule occupies a posi ion oughly in he plane de ined
by he cen al y ium a om and he wo ni ogen a oms o he guanidina o ligand. To minimize
s e ic epulsion wi h he ligand 2,6-diisop opylphenyl g oups, he wo alkyl moie ies occupy
posi ions abo e and below his plane. The bond leng hs om he cen al y ium a om o he
ligand ni ogen a oms a e 2.349(2) and 2.335(2) Å. In compa ison o he ela ed complex
epo ed by Hessen and co-wo ke s [(A NC(NMe2)NA )Y(CH2SiMe3)2 h ][4]
6. Syn hesis and S uc u e o a T inuclea Y ium Polyhyd ide Clus e S abilized by a Bulky Guanidina o Ligand
60
(A = 2,6-diisop opylphenyl) he ound C–Y bond dis ances o 2.378(3) and 2.391(3) Å in
compound 1 a e sligh ly longe han he ones in he Hessen compound (2.374(4) and 2.384(4)
Å).
Figu e 1. Molecula s uc u e o compound 1. Ellipsoids a e d awn on he 50 % p obabili y le el. Ca bon a oms a e
shown as sphe es and hyd ogen a oms a e omi ed o cla i y. Selec ed bond leng hs [Å] and angles [°]:C2–Y1
2.378(3), C3–Y1 2.391(3), C1–N1 1.346(4), C1–N2 1.350(4), C1–N3 1.366(4), N1–Y1 2.349(2), N2–Y1 2.335(2),
O1–Y1 2.382(2), N1 C1 N2 111.9(3).
Hyd ogenolysis o compound 1 a 0°C (2 ba H2 p essu e) a o ded clean o ma ion o
he inuclea polyhyd ide complex [{(PipGu)YH2}3 h 2] (2, Scheme 2) as indica ed by he NMR
s udies and XRD analysis.
Scheme 2. Syn hesis o 2.

6. Syn hesis and S uc u e o a T inuclea Y ium Polyhyd ide Clus e S abilized by a Bulky Guanidina o Ligand
61
1H NMR in es iga ions o compound 2, in con as o he s udies o compound 1, ga e
a he b oad esonance peaks o he h ee guanidina o ligands, he wo coo dina ed h
molecules and a sha p qua e o he six hyd ides (JYH = 18.5 Hz). In solu ion, we ace a
complex dynamic beha io . The h ee guanidina o ligands a e no equi alen which can be
explained by he ac , ha wo o he h ee y ium cen e s ha e a coo dina ed h molecule and
he e o e he o a ion in wo o he h ee ligands is hinde ed a oom empe a u e. All six
hyd ides gi e ise o a single qua e a δ = 6.26 ppm due o coupling wi h he h ee y ium
a oms. This shows ha he hyd ides, in solu ion, a e all equi alen and e y luxional in he ime
scale o NMR spec oscopy and a e no dis inguishable like in he solid-s a e s uc u e. Repo s
on o he inuclea y ium hexahyd ide complexes a e in ag eemen wi h ou inding.[3b,p,l] To ge
a deepe insigh in o he dynamic beha io o compound 2 we ca ied ou a iable empe a u e
1H NMR s udies (Figu e 2). Upon hea ing o 100°C he h ee guanidina o ligands gi e ise o a
single se o p o on esonances as can be seen in Figu e 2 B). This con i med ha he
b oadening o he ligand signals a e due o hind ance in o a ion a oom empe a u e and/o an
equilib ium in coo dina ion and decoo dina ion o h . The qua e a δ = 6.26 ppm shows peak
b oadening down o -35°C. A his empe a u e, he hyd ides s a o become inequi alen and
hei as skipping is hinde ed as seen in Figu e 2 C). Un o una ely, he limi ing spec a whe e
he µ3- and µ2-hyd ides become dis inguishable could no be ob ained.
6. Syn hesis and S uc u e o a T inuclea Y ium Polyhyd ide Clus e S abilized by a Bulky Guanidina o Ligand
62
Figu e 2. A) 1H NMR spec um o 2 (D8- oluene, , 7.6 o 0.4 ppm). B) 1H high empe a u e NMR spec a o 2 (D8-
oluene, 100°C, 7.6 o 0.4 ppm). C) 1H a iable low empe a u e NMR spec a o 2 (D8- oluene, -65 o 10°C, 6.50 o
5.95 ppm).
A molecula s uc u e o compound 2 is depic ed in Figu e 3 and a mo e de ailed iew o
he co e s uc u e wi h pe iphe al ligands educed is shown in Figu e 4. Selec ed in e a omic
dis ances and bond leng hs a e summa ized in Table 1. De ails on he XRD analysis o
compound 1 and 2 a e gi en in Table 2.
6. Syn hesis and S uc u e o a T inuclea Y ium Polyhyd ide Clus e S abilized by a Bulky Guanidina o Ligand
63
Figu e 3. Molecula s uc u e o compound 2. Ellipsoids a e d awn on he 50 % p obabili y le el. Ca bon a oms a e
shown as sphe es and non hyd ide hyd ogen a oms a e omi ed o cla i y.
Figu e 4. De ailed iew o he clus e co e wi h pe iphe al ligands d awn as NCN moie ies and h molecules as O
a oms.
6. Syn hesis and S uc u e o a T inuclea Y ium Polyhyd ide Clus e S abilized by a Bulky Guanidina o Ligand
64
Table 1. Selec ed in e a omic dis ances and bond leng hs [Å] o compound 2.
N–Y (a e age alue)
2.387
O–Y (a e age alue)
2.362
Y(1,2,3)–H5
2.22(4), 2.16(4), 2.12(4)
Y(1,2,3)–H6
2.11(4), 2.11(4), 2.24(4)
Y(1,2)–H1
2.20(4), 2.17(4)
Y(2,3)–H2
2.09(4), 2.17(4)
Y(1,3)–H3
2.14(4), 1.93(3)
Y(1,3)–H4
2.01(4), 2.04(4)
Y1–Y2
3.5457(6)
Y1–Y3
3.1697(5)
Y2–Y3
3.4293(6)
Compound 2 c ys alizes in he monoclinic spaceg oup P2(1)/c wi h a n-hexane molecule
pe asymme ic uni . Each Y a om in complex 2 bea s a guanidina o ligand in he same N,N’-
dihap o mode like in he p ecu so complex 1 bu wi h longe Y-N dis ances due o highe
coo dina ion numbe o he y ium a oms. The h ee y ium a oms de ine a iangle. Fou o he
six hyd ide ligands b idge one o he h ee Y---Y edges in a µ2 mode, meaning one o he edges
is b idged by wo µ2-hyd ides while he o he wo edges a e b idged by only one µ2-hyd ide. The
las wo hyd ides a e capping he sides o he Y3 plane in a µ3 ashion. The Y---Y edge b idged
by wo hyd ides is signi ican ly sho e han he wo o he edges (3.1697(5) Å in compa ison o
3.4293(6) and 3.5457(6) Å, espec i ely). This Y---Y dis ance is he second sho es e e
epo ed, he sho es being 3.1648(7) Å epo ed by Hou and co-wo ke s.[3p] O he (YH2)3
clus e compounds ha e Y-H and Y---Y dis ances in he ange om 2.06(4) o 2.37(4) Å and
3.1648(7) o 3.6841(2) Å.[3b,p,l]
7. Te na y Ra e-Ea h T ansi ion-Me al Polyhyd ide Clus e Compounds
71
on epo o Sla e .[15] 1H NMR s udies a oom empe a u e showed single s in he hyd ide
egion wi h a 2:1 a io o he six hyd ide ligands in compound 1 a

= –13.69 (4H, JWH = 83.3
Hz) and –13.27 ppm (2H, JWH = 104.1 Hz). These signals show an up ield shi in compa ison o
he signal a –12.26 ppm o he educ [Cp2WH2]. The obse ed JWH coupling cons an o 83.3
Hz is g ea e han ha o [Cp2WH2] o 73.0 Hz. The same e ec was epo ed o he
compa able compounds [Cp*2Y(µ-η1:η5-C5H4)(µ-H)2WCp] (JWH = 78.0 Hz, Cp* =
pen ame hylcyclopen adienyl)[8a] and [(E 3P)2(H)I (µ-η1:η5-C5H4)H2WCp] wi h JWH coupling
cons an s o 92.4 Hz and 95.2 Hz.[16] The second JWH coupling cons an o 104.1 Hz is e en
g ea e and migh indica e ha he hyd ide ligands on he b idging ungs enocene moie y a e
bound in a µ3- ashion by W3, Lu1 and Lu2. The C–H ac i a ed Cp ligands showed signals ha
one would expec o a mi o symme ic C5H4 moie y wi h wo single s pe ac i a ed Cp ligand
gi ing h ee se s o signals in a 2:1:1 a io.
Figu e 1. ORTEP d awing o compound 1 wi h 50% he mal ellipsoids. Hyd ogen a oms ha e been omi ed o cla i y.
Selec ed bond leng hs [Å]: Lu1–O1 2.107(11), Lu2–O2 2.081(10), Lu1–W2 3.1211(10), Lu2–W1 3.1155(9), Lu1–C1
2.485(14), Lu2–C1 2.558(14), Lu1–C28 2.554(14), Lu2–C28 2.493(15), Lu1–C63 2.366(17), Lu2–C23 2.315(17),
Cpcen oid–W1 1.965, C5H4cen oid–W1 1.927, Cpcen oid–W2 1.954, C5H4cen oid–W2 1.935, C5H4cen oid–W3 1.932 (a e age
alue).
The selec i e clus e o ma ion ia C–H bond ac i a ion indica i e by he good isola ed
yield o 1 inspi ed us o in es iga e he o ma ion o e na y polyhyd ide clus e s. We chose
[Lu(OA )(Cp2Re)R( h )] as a p omising and a he eac i e educ (Scheme 2).[13c] Reac ing
equimola amoun s o [Lu(OA )(Cp2Re)R( h )] wi h [Cp2WH2] in benzene a oom empe a u e
lead o he o ma ion o he ime allic polyhyd ide clus e compound 2a in 48% yield (Scheme
2). To he bes o ou knowledge, compound 2a is he i s example o a RE-me al polyhyd ide
clus e ea u ing h ee di e en me als as was e ealed by XRD and NMR s udies (Figu e 2).

7. Te na y Ra e-Ea h T ansi ion-Me al Polyhyd ide Clus e Compounds
72
Compound 2a is well soluble in a oma ic sol en s and shows no solubili y in alipha ic
hyd oca bons.
Scheme 2: Syn hesis o 2a and 2b.
One o he lu e ium cen e s in 2a is i e coo dina e by one phenola o ligand, h ee C–H
ac i a ed Cp ings, and a henium a om. The o he lu e ium cen e has he coo dina ion numbe
en con aining a phenola o ligand, h ee C–H ac i a ed Cp ligands, and wo ungs en a oms
each b idged by wo µ2-hyd ides.
Figu e 2.ORTEP d awing o 2a wi h 50% he mal ellipsoids. Hyd ogen a oms ha e been omi ed o cla i y. Selec ed
bond leng hs [Å]: Lu1–O1 2.109(5), Lu2–O2 2.082(5), Lu1–W1 3.1760(5), Lu1–W2 3.2033(5), Lu2–Re1 2.7986(5),
Lu1–C10 2.434(8), Lu1–C15 2.608(8), Lu1–C30 2.543(9), Lu2–C10 2.464(7), Lu2–C15 2.440(8), Lu2–C30 2.430(8),
Cpcen oid–W1 1.889, C5H4cen oid–W1 1.867, Cpcen oid–W2 1.984, C5H4cen oid–W2 1.918, Cpcen oid–Re1 1.869,
C5H4cen oid–Re1 1.857.
The Lu–Re bond dis ance is 2.7986(5) Å, which is way sho e han he sum o he
co alen adii o henium and lu e ium (3.38 Å) based on Al a ez and co-wo ke s da a,[14] sho e
7. Te na y Ra e-Ea h T ansi ion-Me al Polyhyd ide Clus e Compounds
73
han he sum o he a omic adii in c ys als (3.1 Å) based on Sla e ,[15] and e en sho e han he
bond leng hs in [Lu(Cp2Re)3] (2.8773(8), 2.8899(7) and 2.8913(8) Å)[13c] and in
[Lu(OA )(ReCp2)R( h )] (2.8498(6) Å).[13e] The Lu–W bond leng hs a e 3.1760(5) and 3.2033(5)
Å. As such, hey a e longe han in 1, bu s ill sho e han he sum o he co alen adii[14] and
he sum o he a omic adii.[15] The hyd ide signals in he 1H NMR spec um o compound 2a a e
shi ed up ield again o

= –13.61 ppm and show a JWH coupling cons an o 82.5 Hz which is in
good ag eemen wi h he inding o compound 1 (JWH = 83.3 Hz). The e a e no u he hyd ide
signals p esen indica ing a non hyd ide-b idged Lu–Re bond. Each o he phenola o ligands
shows one se o signals a oom empe a u e.
Finally, we became in e es ed in syn hesizing he molybdenum analogue o 2a. The
equimola eac ion o [Cp2MoH2] wi h [Lu(OA )(Cp2Re)R( h )] in benzene ga e he isos uc u al
he e omul ime allic polyhyd ide clus e 2b in 52% yield (Figu e 3 and Scheme 2). The Lu–Mo
bond dis ances o 3.2025(12) and 3.1613(9) Å a e sho e han he sum o he co alen adii o
3.41 Å based on epo o Al a ez and co-wo ke s,[14] and in good ag eemen wi h he sum o he
a omic adii o 3.2 Å based on epo o Sla e .[15] Again, an up ield shi o he single a

= –
10.25 ppm accoun ing o ou hyd ide p o ons can be seen in he 1H NMR spec um, eco ded
a oom empe a u e, in compa ison o he single a

= –8.80 ppm o he hyd ides in
[Cp2MoH2].
Figu e 3.ORTEP d awing o 2b wi h 50% he mal ellipsoids. Hyd ogen a oms ha e been omi ed o cla i y. Selec ed
bond leng hs [Å]: Lu1–O1 2.111(7), Lu2–O2 2.074(7), Lu1–Mo1 3.2025(12), Lu1–Mo2 3.1613(9), Lu2–Re1
2.8058(6), Lu1–C5 2.412(10), Lu1–C11 2.608(13), Lu1–C28 2.591(12), Lu2–C5 2.484(10), Lu2–C11 2.403(12), Lu2–
C28 2.426(11), Cpcen oid–Mo1 1.982, C5H4cen oid–Mo1 1.917, Cpcen oid–Mo2 1.965, C5H4cen oid–Mo2 1.888, Cpcen oid–
Re1 1.879, C5H4cen oid–Re1 1.852.
Quan um chemical calcula ions we e pe o med o loca e he missing hyd ide-a omic
posi ions in compound 2a and o analyze hei ole in W–Lu bonding compa ed o Re–Lu
7. Te na y Ra e-Ea h T ansi ion-Me al Polyhyd ide Clus e Compounds
74
bonding in he clus e compounds 2. Fo ha pu pose, ull s uc u e op imiza ion has been
in oked on a sligh ly simpli ied model s uc u e 2a’ (subs i u ing H o he e -bu yl g oups) o
compound 2a. Fo he scala - ela i is ic (ZORA app oach)[17] calcula ions wi h he ADF[18]
p og am sys em he DFT/BP86[19] me hod and in e nal Sla e - ype iple-ze a basis se s wi h wo
se s o pola iza ion unc ions (“TZ2P”, wi h ozen small co e) ha e been employed. A e 100
op imiza ion cycles he –OPhen g oups we e ixed, and he emaining a om posi ions we e
u he op imized. A g adien s o less han 0.3 mHa eeÅ–1, he p ocedu e was inished. The
inal s uc u e, especially he inne me al pa , is e y simila o he one om expe imen al
s uc u e de e mina ion.
Figu e 4. Op imized s uc u e o model 2a’ wi h ELI-D/QTAIM basin in e sec ions. Hyd idic H a oms a e displayed as
blue sphe es, in e sec ion o co esponding ELI-D basin yields a egion (deep blue) con ained in he QTAIM H a om,
a egion ( ed) con ained in he W QTAIM a om, and a egion (ligh blue) con ained in Lu1 a om; in e sec ion o he
ELI-D Lu-Re bond basins yields a egion ( ed) belonging o he Re a om, and a egion (ligh blue) belonging o he
Lu2 a om; all basins a e c opped a densi y alues below 0.0001 e/Boh –3.
I displays dis ances d(Lu1–W) o 3.13 and 3.14 Å ( s. 3.18 and 3.20 Å om
expe imen al s uc u e de e mina ion), d(Lu2–Re1) = 2.81 Å ( s. 2.80 Å om expe imen ), and
d(W–H) be ween 1.72 and 1.73 Å wi h angles H-W-H o 87.3° and 87.6°. Unde he same
compu a ional condi ions a sepa a e s uc u e op imiza ion o he [Cp2WH2] molecule yields
d(W–H) = 1.71 Å and angle H-W-H = 78.6°, which shows ha he dis ances W–H only
ma ginally inc ease upon coo dina ion o Lu, whe eas he angle H-W-H no ably widens by 9°.
Conce ning he elec onic s uc u e, a HOMO-LUMO gap o 1.5 eV is ound, in which he
HOMO, HOMO-1 and HOMO-2 can be classi ied as nominal Re(5d) o bi als. As has been
p e iously done,[9c, 13c,d,e] posi ion-space bonding analysis (p og am DG id[20]) by using he
elec on densi y (QTAIM me hod)[21] and he elec on localizabili y indica o (ELI-D)[22] has been
employed. The nega i e alues Qe (H) = –0.35 ±0.01 o he QTAIM e ec i e cha ges o he
7. Te na y Ra e-Ea h T ansi ion-Me al Polyhyd ide Clus e Compounds
75
ou W-H-Lu1 b idging H a oms was consis en wi h hei hyd idic cha ac e . These alues we e
ound o be e y simila o he ones Qe (H) = –0.30 in he isola ed [Cp2WH2] molecule. Applying
he me hod o ELI-D/QTAIM basin in e sec ion[23] yields ha W–H bonding is pola -co alen wi h
70% o he ELI-D basin in eg a ed cha ge densi y o each hyd idic H a om belongs o he
co esponding QTAIM H a om and 26% o he QTAIM W a om (Figu e 4). Only a iny amoun o
3% is con ained in he QTAIM Lu1 a om. Taking in o accoun he posi i e e ec i e cha ge Qe
(Lu1) = +1.9, his inding is o be in e p e ed as a e y ionic ype o bonding in e ac ion H–Lu1,
which is consis en wi h he i ually unchanged dis ances d(W–H) compa ed o isola ed
[Cp2WH2]. Conce ning di ec W–Lu1 bonding a co esponding ELI-D maximum was no
displayed; howe e owing o he b idging H a oms, his would no be expec ed o occu . As a
signa u e o W–Lu1 bonding, inside he quad ila e al W-H’-Lu1-H’’, a egion wi h nega i e
alues o he Laplacian o ELI-D,[22c] which ex ends pe pendicula o he W–Lu1 in e connec ion
line, can be ound. Such a egion does no occu in he isola ed molecule [Cp2WH2], bu is ound
also o he Lu2–Re bonding si ua ion, in which ELI-D a ac o s addi ionally signi y he co alen
bonding in e ac ion. In comple e analogy o p e ious cases o pola -co alen a e ea h-
ansi ion me al bonding,[9c, 13,c,d,e] unsuppo ed Lu2–Re bonding is indica ed by co esponding
ELI-D maxima wi h 1.30 elec ons in wo Lu2–Re bonding ELI-D basins (me ged in o one
supe basin). The ELI-D/QTAIM in e sec ion p ocedu e showed ha 79% o he basin popula ion
is con ained in he Re, and 16% in he Lu QTAIM a om, which is simila o p e ious cases.
7.3 Conclusions
In conclusion, ansi ion me al dihyd ide complexes o he o mula [Cp2MH2] (M = Mo, W)
eac wi h a e ea h me al bis- and monoalkyl complexes and unde go mul iple C–H bond
ac i a ion s eps, leading o bina y and e na y RE-me al polyhyd ide clus e compounds. The
e na y clus e s display pola ReLu bonds and W–H∙∙∙Lu in e ac ions, whe e he hyd ide
a oms a e pola -co alen ly coo dina ed o W, and he in e ac ion wi h Lu is e y ionic.
Addi ionally, a co alen di ec in e ac ion W–Lu is indica ed by ELI-D analysis. Conce ning he
b oade s a egy o building highe agg ega ed e na y RE–TM polyhyd ide clus e s [Cp2MH2]
ep esen s a p omising ansi ion me al building block. In he u u e wo k, we a e in e es ed in
s udying he eac i i y o he clus e compounds in oduced he ein.
7.4 Acknowledgmen s
Financial suppo by he Deu sche Fo schungsgemeinscha (DFG, KE 756/ 21-1, WA 956/3-1)
is g a e ully acknowledged.
7. Te na y Ra e-Ea h T ansi ion-Me al Polyhyd ide Clus e Compounds
76
Suppo ing In o ma ion a ailable: Suppo ing in o ma ion o his a icle con ains de ailed
in o ma ion on he syn hesis and cha ac e iza ion o he compounds desc ibed he ein, as well
as c ys allog aphic de ails o he s uc u es de e mined by XRD. I is a ailable on he WWW
unde h p://dx.doi.o g/10.1002/chem.201301290.
7.5 Re e ences
[1] Fo some examples, see: a) R. M. Bullock, M. H. Voges, J. Am. Chem. Soc. 2000, 122,
12594–12595; b) R. Noyo i, Angew. Chem. 2002,114, 2108–2123; Angew. Chem. In .
Ed. 2002, 41, 2008–2022; c) C. Deu sch, N. K ause, B. H. Lipshu z, Chem. Re . 2008,
108, 2916–2927; d). H. Nakazawa, M. I azaki, Top. O ganome . Chem. 2011, 33, 27–81.
[2] a) L. Schlapbach, A. Zü el, Na u e 2001, 414, 353–358; b) E. Da id, J. Ma e . P oc.
Technol. 2005, 162, 169–177; c) B. Sakin una, F. Lama i-Da k im, M. Hi sche , In . J.
Hyd ogen Ene gy 2007, 32, 1121–1140; d) S. F. Ma a , P og. Solid S a e Chem. 2010,
38, 1–37; e) S. F. Ma a , P og. Solid S a e Chem. 2012, 40, 31–40.
[3] NiMH ma e ials a e used in ba e ies o hyb id ca s, o example in he Toyo a P ius
[4] T. Shima, Y. Luo, T. S ewa , R. Bau, G. J. McIn y e, S. A. Mason, Z. Hou, Na . Chem.
2011, 3, 814–820.
[5] W. J. E ans, J. H. Meadows, T. P. Hanusa, J. Am. Chem. Soc. 1984, 106, 4454–4460.
[6] The localiza ion o H a oms is a undamen al p oblem in polyhyd ide complexes o hea y
a oms: G. G. Hla ky, R. H. C ab ee, Coo d. Chem. Re . 1985, 65, 1–48.
[7] a) M. L. H. G een, A. K. Hughes, D. M. Michaelidou, P. Moun o d, J. Chem. Soc.,
Chem. Commun. 1993, 591–593; b) D. M. Michaelidou, M. L. H. G een, A. K. Hughes, P.
Moun o d, A. N. Che nega, Polyhed on 1995, 14, 2663–2675.
[8] a) N. R. Radu, P. K. Gan zel, T. D. Tilley, J. Chem. Soc., Chem. Commun. 1994, 1175-
1176; b) Y. Takenaka, Z. Hou, O ganome allics 2009, 28, 5196–5203; c) T. Shima, Z.
Hou, Chem. Eu . J., 2013, 19, 3458–3466
[9] a) D. Al a ez, J ., K. G. Caul on, W. J. E ans, J. W. Zille , J. Am. Chem. Soc. 1990, 112,
5674–5676; b) D. Al a ez, J ., K. G. Caul on, W. J. E ans, J. W. Zille , Ino g. Chem.
1992, 31, 5500–5508; c) M. V. Bu o skii, O. L. Tok, F. R. Wagne , R. Kempe, Angew.
Chem. 2008, 120, 6569–6572; Angew. Chem. In . Ed. 2008, 47, 6469–6472; d) T.
Shima, Z. Hou, Chem. Le . 2008, 37, 298–299; e) T. Shima, Z. Hou, O ganome allics
2009, 28, 2244–2252.
[10] A. P. Sobaczynski, T. Baue , R. Kempe, O ganome allics, 2013, 32, 1363–1369.
[11] P. Cui, T. P. Spaniol, J. Okuda, O ganome allics, 2013, 32, 1176–1182.

7. Te na y Ra e-Ea h T ansi ion-Me al Polyhyd ide Clus e Compounds
77
[12] Fo ecen e iews see: a) D. Pa el, S. T. Liddle, Re . Ino g. Chem. 2012, 32, 1–22; b) B.
Oelke s, M. V. Bu o skii, R. Kempe, Chem. Eu . J. 2012, 18, 13566–13579.
[13] a) I. P. Bele skaya, A. Z. Voskoboyniko , E. B. Chuklano a, N. I. Ki illo a, A. K.
Shes ako a, I. N. Pa shina, A. I. Guse , G. K.-I. Magomedo , J. Am. Chem. Soc. 1993,
115, 3156–3166; b) P. L. A nold, J. McMas e , S. T. Liddle, Chem. Commun. 2009, 818–
820; c) M. V. Bu o skii, C. Dö ing, V. Bezugly, F. R. Wagne , Y. G in, R. Kempe, Na .
Chem. 2010, 2, 741–744; d) C. Dö ing, A.-M. Die el, M. V. Bu o skii, V. Bezugly, F. R.
Wagne , R. Kempe, Chem. Eu . J. 2010, 16, 10679-10683; e) M. V. Bu o skii, O. L. Tok,
V. Bezugly, F. R. Wagne , R. Kempe, Angew. Chem. 2011, 123, 7873–7840; Angew.
Chem. In . Ed. 2011, 50, 7695-7698; ) M. P. Blake, N. Kal soyannis, P. Moun o d, J.
Am. Chem. Soc. 2011, 133, 15358–15361.
[14] B. Co de o, V. Gómez, A. E. Pla e o-P a s, M. Re és, J. Eche e ía, E. C emades, F.
Ba agán, S. Al a ez, Dal on T ans. 2008, 2832–2838.
[15] J. C. Sla e , J. Chem. Phys. 1964, 41, 3199–3204.
[16] P. S. P egosin, A. Togni, L. M. Venanzi, Angew. Chem. 1981, 93, 684; Angew. Chem.
In . Ed. 1981, 20, 668–669.
[17] E. an Len he, A. E. Ehle s and E. J. Bae ends, J. Chem. Phys. 1999, 110, 8943–8953.
[18] a) G. e Velde, F. M. Bickelhaup , S. J. A. an Gisbe gen, C. Fonseca Gue a, E. J.
Bae ends, J. G. Snijde s and T. Ziegle , J. Compu . Chem. 2001, 22, 931–967; b) C.
Fonseca Gue a, J.G. Snijde s, G. e Velde, E. J. Bae ends, Theo . Chem. Acc. 1998,
99, 391–403; c) ADF2012.01, SCM, Theo e ical Chemis y, V ije Uni e si ei ,
Ams e dam, The Ne he lands, h p://www.scm.com
[19] a) A. D. Becke, Phys. Re . A 1988, 38, 3098-3100; b) J. P. Pe dew, Phys. Re . B 1986,
33, 8820-8824.
[20] M. Kohou , p og am DG id, e sion 4.6, Radebeul, Ge many, 2012.
[21] R. F. W. Bade , A oms in Molecules: A Quan um Theo y, Ox o d Uni e si y P ess,
Ox o d, 1994.
[22] a) M. Kohou , Fa aday Discuss. 2007, 135, 43–54; b) F. R. Wagne , V. Bezugly, M.
Kohou , Yu. G in, Chem. Eu . J. 2007, 13, 5724–5741; c) F. R. Wagne , M. Kohou , Yu.
G in, J. Phys. Chem. A 2008, 112, 9814–9828.
[23] a) S. Raub, G. Jansen, Theo . Chem. Acc. 2001, 106, 223–232; b) G. Jansen, M.
Schuba , B. Findeis, L. H. Gade, I. J. Scowen, M. McPa lin, J. Am. Chem. Soc. 1998,
120, 7239–7251.
7. Te na y Ra e-Ea h T ansi ion-Me al Polyhyd ide Clus e Compounds
78
7.6 Suppo ing In o ma ion
7.7 Gene al
All manipula ions we e pe o med wi h igo ous exclusion o oxygen and mois u e in Schlenk-
ype glasswa e on a dual mani old Schlenk line o in a N2 illed glo e box (mB aun 120-G) wi h a
high-capaci y eci cula o (<0.1ppm O2). Sol en s we e d ied by dis illa ion om sodium
wi e/benzophenone. Comme cial [Cp2WH2] (ABCR) was used as ecei ed. [Lu(OA )R2( h )2],[1]
[Lu(OA )(ReCp2)R( h )],[1] [Cp2MoH2][2] and [Cp2ReH][3] we e p epa ed acco ding o published
p ocedu es. Deu e a ed sol en s we e ob ained om Camb idge Iso ope Labo a o ies and we e
degassed, d ied and dis illed p io o use. NMR spec a we e eco ded on Va ian Uni y 300 MHz
and Va ian Uni y 400 MHz ins umen s a ambien empe a u e. The chemical shi s a e
epo ed in ppm ela i e o he in e nal TMS o esidual sol en signals. Elemen al analyses
(CHN) we e de e mined using a Va io EL III ins umen . X- ay c ys al s uc u e analyses we e
pe o med by using a STOE-IPDS II equipped wi h an Ox o d C yos eam low- empe a u e uni .
S uc u e solu ion and e inemen was accomplished using SIR97,[4] SHELXL97[5] and WinGX.[6]
C ys allog aphic de ails a e summa ized in Table 1. CCDC-932376 ( o 1), -932377 ( o 2a), and
-932378 ( o 2b) con ain he supplemen a y c ys allog aphic da a o his pape . These da a can
be ob ained ee o cha ge om The Camb idge C ys allog aphic Da a Cen e ia
www.ccdc.cam.ac.uk/da a_ eques /ci .
7. Te na y Ra e-Ea h T ansi ion-Me al Polyhyd ide Clus e Compounds
79
7.8 De ails o he X- ay c ys al s uc u e analyses
Table 1: De ails o he X- ay c ys al s uc u e analyses.
Compound
1
2a
2b
C ys al sys em
iclinic
monoclinic
monoclinic
space g oup
P-1
P21/c
P21/c
a [Å]
14.5190(7)
19.4320(5)
19.2850(5)
b [Å]
14.5450(7)
18.5290(4)
18.1160(5)
c [Å]
16.5350(8)
19.4310(5)
19.4870(5)
α [˚]
86.651(4)
90.00
90.00

[˚]
68.746(4)
119.476(2)
117.975(2)
γ [˚]
76.211(4)
90.00
90.00
V [Å3]
3159.0(3)
6090.7(3)
6012.6(3)
Z
2
4
4
ρ (calcd.) [g cm-3]
1.950
2.026
1.859
µ [mm-1]
8.580
8.999
5.709
T [K]
133
133
133
2θ ange [˚]
2.64-50.39
2.41-50.06
2.39-53.91
Re lec ions unique
10601
10239
12771
Re l. obs . [I > 2σ(I)]
5588
7554
7715
Pa ame e s
709
706
640
R1, wR2 [I > 2σ(I)]
0.0506, 0.1134
0.0336, 0.0703
0.0555, 0.1348
R1, wR2 (all da a)
0.0935, 0.1217
0.0526, 0.0741
0.0929, 0.1474
7. Te na y Ra e-Ea h T ansi ion-Me al Polyhyd ide Clus e Compounds
80
7.9 Syn hesis and cha ac e iza ion o he clus e compounds
Syn hesis o [C58H74Lu2O2W3] (1):
[Cp2WH2](71 mg, 225 µmol) was dissol ed in benzene (1.5 mL) and added o a solu ion o
[Lu(OA )R2( h )2] (105 mg, 150 µmol) in benzene (1.5 mL). The eac ion mix u e was kep a
oom empe a u e o 24 hou s wi hou s i ing o o m a yellow c ys alline p ecipi a e.
Yield: 0.096 g, 75%. Yellow p ism like c ys als sui able o X-Ray s uc u e analysis whe e
g own a he laye in e ace by eezing and laye ing bo h educ benzene solu ions and le ing
hem haw slowly. C58H74Lu2O2W2 (1704.66): Calcd. C 40.87, H 4.38; ound C 41.25, H 4.35; 1H
NMR (400 MHz, [D6]benzene): δ = -13.69 (s, 4H, JWH = 83.3 Hz, W-H), -13.27 (s, 2H, JWH =
104.1 Hz, W-H), 1.66 (s, 36H, C(CH3)3), 4.13 (s, 4H, C5H4), 4.24 (s, 10H, C5H5), 4.36 (s, 4H,
C5H4), 4.53 (s, 2H, C5H4), 4.64 (s, 2H, C5H4), 5.16 (s, 2H, C5H4), 5.54, (s, 2H, C5H4), 6.85 ( , 2H,
JHH = 7.7 Hz, p-C14H21O), 7.38 (d, 4H, JHH = 7.7 Hz, m-C14H21O) ppm.Due o he poo solubili y
o compound 1 meaning ul 13C NMR expe imen s we e no possible.
Syn hesis o [C58H73Lu2O2ReW2] (2a):
To [Cp2WH2] (31.6 mg, 100 µmol) in benzene (1 mL) was added [Lu(OA )(Cp2Re)R( h )]
(85.6 mg, 100 µmol) in benzene (2 mL). The eac ion mix u e u ned om ligh yellow o o ange
wi hin one hou . Concen a ion in acuum yielded yellow block-like c ys als a 10° C.
Yield: 0.408 g, 48%.C58H73Lu2O2ReW2 (1706.02): Calcd. C 40.83, H 4.31; ound C 40.29,
H 4.16; 1H NMR (400 MHz, [D6]benzene): δ = -13.61 (s, 4H, JWH = 82.5 Hz, W-H), 1.53 (s, 18H,
C(CH3)3), 1.65 (s, 18H, C(CH3)3), 4.20 (s, 5H, (C5H5)Re), 4.24 (s, 10H, (C5H5)W), 4.40 (s, 2H,
C5H4), 4.55 (s, 2H, C5H4), 4.83 (s, 2H, C5H4), 5.21 (s, 2H, C5H4), 6.83 ( , 1H, JHH = 8,0 Hz, p-
C14H21O), 6.85 ( , 1H, JHH = 8.2 Hz, p-C14H21O), 7.29 (d, 2H, JHH = 7.7 Hz, m-C14H21O), 7.38 (d,
2H, JHH = 7.7 Hz, m-C14H21O);13C NMR (100 MHz, [D6]benzene): δ = 32.28 (C(CH3)3), 35.48
(C(CH3)3), 64.55 ((C5H5)Re), 71.62 ((C5H5)W), 73.73 (C5H4), 78.10 (C5H4), 117.67 (p-C14H21O),
125.63 (m-C14H21O), 137.90 (o-C14H21O), 163.16 (i-C14H21O) ppm.
Syn hesis o [C58H73Lu2Mo2O2Re] (2b):
To [Lu(OA )(Cp2Re)R( h )] (0.428 g, 500 µmol) in benzene (10 mL) was added [Cp2MoH2]
(0.114 g, 500 µmol) in benzene (5 mL). The yellow solu ion u ned da k o ange o b own wi hin
one hou . Concen a ion in acuum ga e yellow c ys als wi h a block shaped habi a 10° C.
Yield: 0.198 g, 52%. C58H73Lu2Mo2O2Re (1530.22): Calcd. C 45.52, H 4.81; ound C 45.02,
H 4.32;1H NMR (400 MHz, [D6]benzene): δ = -10.25 (s, 4H, Mo-H), 1.52 (s, 18H, C(CH3)3), 1.65
(s, 18H, C(CH3)3), 4.20 (s, 5H, (C5H5)Re), 4.24(s, 2H,C5H4), 4.36 (s, 10H, (C5H5)Mo), 4.53 (s,
9. Acknowledgemen s / Danksagung
87
9.2 Danksagung
Mein au ich ige Dank gil meinem akademischen Leh e
P o . D . Rhe Kempe
ü die Möglichkei , dieses seh in e essan e Thema in seinem A bei sk eis zu bea bei en, die
une müdliche Diskussionsbe ei scha und das s e e In e esse am Fo gang de A bei , so wie
die gewäh e wissenscha liche F eihei bei de Bea bei ung des Themas. Wei e hin danke ich
Ihm ü die exzellen en A bei sbedingungen und die Ein üh ung in die Rön gen-
eink is alls uk u analyse.
D . Win ied P. K e schme danke ich ü s e e Diskussionsbe ei scha , Mo i a ion,
Un e s ü zung und ü das Ko ek u lesen meine Publika ionen.
D . Ch is ian Dö ing danke ich he zlich ü die Ein üh ung in die Lan hanoidchemie und ü die
gemeinsam e b ach e Zei im Labo und auße halb des Labo s.
D . Awal Noo möch e ich au ich ig danken ü die Mo i a ion, Un e s ü zung und s e e
Hil sbe ei scha in iele lei Hinsich .
D . To s en I gang danke ich ielmals ü das Ko ek u lesen de Zusammen assung und de
Einlei ung.
Ein besonde es Dankeschön gil den on mi be eu en P ak ikan en Thomas Wi mann,
Sab ina Sachau, And eas Ma k, Michael Vogel und F anziska Speckne ü ih e Hil e und
A bei .
He zlich bedanken möch e ich mich bei Wal e K emni z, Heidi Maisel, Simone O , Ma lis
Schilling, Sand a Kelle und Anna-Ma ia Die el ü die Hil es ellungen und Un e s ü zung bei
Ve wal ungsangelegenhei en und Zua bei en im Labo all ag.
Bei meinen Labo kollegen D . Win ied K e schme , Ch is ian Hübne , Isabelle Hass und Anna-
Ma ia-Die el möch e ich mich ü die gu e A bei sa mosphä e und Hil sbe ei scha bedanken.

9. Acknowledgemen s / Danksagung
88
Meinen A bei skollegen und dem gesam en A bei sk eis Kempe, D . Ch is ine Denne , Anna-
Ma ia-Die el, Julia Ewe , Daniel Fo be g, Ma in F ied ich, Isabelle Haas, Muhammad Ha eez,
Jus us He mannsdö e , Toni Hille, Ch is ian Hübne , D . To s en I gang, D . Win ied P.
K e schme , Sonja Lippe , Geo g Lochne , S e an Michlik, D . Awal Noo , Johannes Obenau ,
D . Benjamin Oelke s, Simone O , Sa a ana Pillai, D . Sada Qayyum, Susanne Ruch, Sab ina
Sachau, S e an Schwa z, Adam Sobaczynski, Emmanuel Sobgwi Tamne, The esa Winkle und
Muhammad Zahee danke ich ganz besonde s ü die gu e A bei sa mosphä e und die schöne
Zei auch absei s des Labo all ags. Des Wei e en bin ich ihnen seh dankba ü die Hil e und
Un e s ü zung, die ich in iele lei Hinsich e ah en habe.
Meine liebenden Familie, meinen Geschwis e n Debo ah Baue , Rebekka Baue , Manuel
Baue , Do o hea Baue , Daniel Baue und Tama a Baciu danke ich aus ie s em He zen ü all
die Au mun e ung wäh end de Zei meine P omo ion. Bei meinen El e n, besonde s bei
meinem Va e Ul ich Baue , möch e ich mich ü die Hil e und Un e s ü zung in jegliche Hinsich
au ich ig bedanken. Ich bin seh glücklich und s olz Teil diese ollen Familie zu sein.
Zule z möch e ich mich bei B ina ü all ih e Liebe, ih Ve s ändnis, die Un e s ü zung,
au mun e nden Wo e und ih en une schü e lichen Glauben und niemals endendes Ve auen
in mich au ich ig und aus ie s em He zen bedanken.
10. Decla a ion / E klä ung
89
10 Decla a ion / E klä ung:
I he eby decla e ha I ha e w i en his wo k by mysel and ha no o he sou ces han hose
men ioned in his wo k ha e been used.
This wo k has so a nei he been submi ed o he Facul y o Biology, Chemis y and Ea h
Sciences a he Uni e si y o Bay eu h no o any o he scien i ic ins i u ion o he pu pose o a
doc o al hesis. I ne e inally ailed a simila doc o al examina ion a any o he uni e si y.
Hie mi e siche e ich an Eides s a , dass ich die o liegende A bei selbs s ändig und nu un e
Ve wendung de angegebenen Hil smi el und Quellen ange e ig habe.
Diese A bei wu de bishe wede an de Fakul ä ü Biologie, Chemie und Geowissenscha en
de Uni e si ä Bay eu h noch eine ande en wissenscha lichen Ein ich ung zum Zwecke de
P omo ion einge eich . Ich habe keine gleicha ige Dok o p ü ung an eine ande en
uni e si ä en Hochschule endgül ig nich bes anden.
Tobias Baue