Iodine(i) complexes incorporating sterically bulky 2-substituted pyridines
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Iodine(i) complexes inco po a ing s e ically bulky 2-subs i u ed py idines
© 2022 The Au ho (s). Published by he Royal Socie y o Chemis y
Published e sion
Wa d, Jas S.; Gomila, Rosa M.; F on e a, An onio; Rissanen, Ka i
Wa d, J. S., Gomila, R. M., F on e a, A., & Rissanen, K. (2022). Iodine(i) complexes inco po a ing
s e ically bulky 2-subs i u ed py idines. RSC Ad ances, 12(14), 8674-8682.
h ps://doi.o g/10.1039/d2 a01390h
2022
Iodine(I) complexes inco po a ing s e ically bulky
2-subs i u ed py idines†
Jas S. Wa d, *
a
Rosa M. Gomila,
b
An onio F on e a
b
and Ka i Rissanen
a
The sil e (I) and iodine(I) complexes o he 2-subs i u ed py idines 2-(diphenylme hyl)py idine (1) and 2-(1,1-
diphenyle hyl)py idine (2), along wi h hei po en ial p o ona ed side p oduc s, we e syn hesised o
in es iga e he s e ic limi a ions o iodine(I) complex o ma ion. The complexes we e cha ac e ised by
1
H
and
1
H–
15
N HMBC NMR, X- ay c ys allog aphy, and DFT calcula ions. The solid-s a e s uc u es o he
sil e (I) and iodine(I) complexes we e ex ensi ely compa ed o he li e a u e and analysed by DFT o
examine he influence o he s e ically bulky py idines and hei anions.
In oduc ion
Since hei ad en in he 1960s,
1,2
halogen(I) (also known as
halonium) ions, X
+
(X ¼B , I), s abilised by a pai o Lewis bases
(L) in he o m [L–X–L]
+
, ha e exis ed as examples o halogen
g oup elemen s o mally in he unusual +1 oxida ion s a e,
hough i was no un il he 1990s ha hey gained mains eam
ecogni ion due o he my iad o o ganic ans o ma ions hey
we e dely demons a ed o effec .
3–5
In addi ion o his u ili y,
halogen(I) ions possess o he a ou able p ope ies a ising om
hei s-hole in e ac ion,
6
mos no ably he eliable high deg ee
o linea di ec ionali y which has been ui ully u ilised in sel -
assembling sup amolecula a chi ec u es,
7–9
and ecen ly in
coo dina ion polyme s such as halogen-bonded o ganic
amewo ks (XOFs).
10
Halogen(I) complexes can be s aigh o wa dly syn hesised
in a one po eac ion by addi ion o an elemen al halogen, X
2
(X
¼B , I) o he analogous 2-coo dina e sil e (I) complex by Ag
+
o
X
+
ca ion exchange,
11,12,14
o as was ecen ly shown, also om 3-
coo dina e sil e (I) complexes ia pa ial ca ion exchange.
15,16
The use o subs i u ed py idines as he s abilising Lewis
bases domina es he li e a u e o halogen(I) complexes, and o
hose examples, i is py idines subs i u ed in he 4-posi ion
which o e whelmingly comp ise he la ges subse ae py i-
dine i sel .
17
The 4-posi ion o coo dina ing py idines is one ha
can be desc ibed as only elec onically affec ing halogen(I) ion
o ma ion, and has been p e iously u ilised o explo e ha
ela ionship in halogen(I) complexes.
11
Wi h espec o he
ela ionship o s e ics owa d halogen(I) o ma ion, cu en ly
he iodine(I) complexes in he li e a u e wi h he mos s e ic
bulk a ound he I
+
ion a e hose inco po a ing 2,6-dime-
hylpy idine (2,6-lu idine) and 2,4,6- ime hylpy idine,
18–22
as
well as a single solid-s a e example o a b omine(I) complex wi h
quinoline as he Lewis base,
23
hough his is no including he
molecula clamps epo ed by E d´
elyi and co-wo ke s as hose
ligands would also p o ide an addi ional s abilising con ibu-
ion ia he chela e effec .
9,11
Ba luenga's eagen , [I(py)
2
]BF
4
(py
¼py idine), he ubiqui ous iodina ion eagen o which iodi-
ne(I) chemis y owes i s cu en enown, is comme cially a ail-
able and demons a es a as scope o u ili y, howe e ,
decomposi ion is obse ed o e ime. The e o e, an expansion
o he py idine scaffold would be an ideal s a ing poin o
explo e he s e ic limi a ions o halogen(I) ions, and hei
po en ial applica ions owa d a new gene a ion o halogen(I)
eagen s.
Resul s and discussion
Syn hesis and solu ion s udies
The sil e (I) complexes [1–Ag–1]PF
6
(1a) and [2–Ag–2]PF
6
(2a)
we e syn hesised quan i a i ely om he wo s e ically bulky
py idine-based ligands, 2-(diphenylme hyl)py idine (1) and 2-
Scheme 1 The syn hesis o sil e (I)(1a,2a) and iodine(I)(1b,2b)
complexes o 2-(diphenylme hyl)py idine (1) and 2-(1,1-diphenyle hyl)
py idine (2).
a
Uni e si y o Jy askyla, Depa men o Chemis y, Jy ¨
askyl¨
a 40014, Finland. E-mail:
james.s.wa d@jyu.
b
Depa men o Chemis y, Uni e si a de les Illes Balea s, C s de Valldemossa km 7.6,
07122 Palma de Mallo ca, Balea es, Spain
†Elec onic supplemen a y in o ma ion (ESI) a ailable: Syn hesis, NMR,
compu a ional de ails, and X- ay. CCDC 2144042–2144045, 2150094–2150097.
Fo ESI and c ys allog aphic da a in CIF o o he elec onic o ma see DOI:
10.1039/d2 a01390h
Ci e his: RSC Ad ., 2022, 12, 8674
Recei ed 2nd Ma ch 2022
Accep ed 14 h Ma ch 2022
DOI: 10.1039/d2 a01390h
sc.li/ sc-ad ances
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(1,1-diphenyle hyl)py idine (2), espec i ely (Scheme 1). The
syn hesis o he iodine(I) analogues, [1–I–1]PF
6
(1b) and [2–I–2]
PF
6
(2b), we e pe o med by addi ion o an equi alen o
elemen al iodine. The eac ions we e all ollowed by
1
H and
1
H–
15
N co ela ed NMR spec oscopy.
The
1
H NMR spec a o he ee ligand 1, oAg
+
complex 1a,
and nally o I
+
complex 1b e ealed ha all peaks demons a e
no iceable shis o each ans o ma ion, wi h he anges o
0.04–0.56 ppm (1 o 1a) and 0.01–0.84 ppm (1a o 1b), he mos
appa en being hose o he downeld py idyl and upeld
me hine esonances ha a e ee om o e lapping chemical
shis wi h he pendan phenyl ings (Fig. 1). Whils he
1
H NMR
da a did p o ide clea indica ions o clean eac ions occu ing,
hey could no hemsel es poin owa d he iden i y o he
p oduc s. I should be no ed ha he py idyl esonances in 1a
(g een) do no ollow he end o shiing owa d downeld as
obse ed o 1 o 1b, which is likely due o he inc eased elec-
on densi y on he py idyl ings due o e o-dona ion wi h he
Ag
+
me al cen e.
In con as , om he
1
H–
15
N HMBC NMR expe imen s, he
15
N NMR chemical shiso 65.4 ppm (1), 118.6 ppm (1a),
and 165.7 ppm (1b) a e cha ac e is ic o he desi ed con e -
sions ha ing been achie ed, esembling esul s obse ed o
o he iodine(I) complexes o 4-subs i u ed py idine
analogues.
12,13
An icipa ing an inc eased likelihood o decom-
posi ion due o he s e ic hind ance o he subs i uen s in he 2-
posi ions o he py idyl ings, he p o ona ed (1c) and hyd o-
nium (1d) complexes we e delibe a ely syn hesised o
compa ison, which ga e
15
N NMR chemical shiso 167.5 and
122.5 ppm, espec i ely. Gi en he eac i i y o halogen(I)
complexes, hei p opensi y o decompose o p o ona ed
species, and he simila i y o he
15
N NMR chemical shiso 1a
o 1d (Dd
15N
¼3.9 ppm) and 1b o 1c (Dd
15N
¼1.8 ppm), cau ion
mus always be aken in cha ac e ising halogen(I) species based
solely on NMR spec oscopy da a. Ne e heless, he iden i y o
1a and 1b we e deni ely con med by single c ys al X- ay
diff ac ion s udies.
The con e sion o he ee ligand 2 o he Ag
+
complex 2a
demons a ed simila changes in he
1
H NMR chemical shisas
obse ed o 1 o 1a, wi h a ange o 0.07–0.90 ppm, and
15
N
NMR chemical shiso 65.1 ppm (2) and 111.4 ppm (2a).
Howe e , despi e he p ecipi a ion o he AgI by-p oduc o
ca ion exchange upon addi ion o elemen al iodine o effec he
ans o ma ion o 2a o 2b, NMR s udies sugges ed ha he
desi ed iodine(I) complex 2b had al eady begun o decompose
wi hin minu es o i s incep ion. The
1
H NMR spec um showed
ha he py idyl p o ons we e signican ly b oadened, and he
concomi an
1
H–
15
N HMBC expe imen ga e a
15
N NMR
chemical shio 121.5 ppm.‡This
15
N NMR chemical shi
was a om he expec ed alue o app oxima ely 165 ppm o
he desi ed iodine(I) complex 2b, hough i did ma ch well o he
independen ly syn hesised hyd onium species [2–H–2]PF
6
(2d),
which had a
15
N NMR chemical shio 123.0 ppm.
Solid-s a e s udies
The solid-s a e s uc u e o 1a con ained wo hal ca ions which
sel -comple ed by symme y, and simila ly 1b con ained jus
one hal , which in bo h ins ances ensu ed ha all N–Ag–N and
N–I–N angles we e symme y en o ced, i.e., pe ec ly linea . The
sligh ly elonga ed Ag–N bond leng hs o 2.151(2) and 2.162(2) ˚
A
in 1a, in combina ion wi h he I–N bond leng h o 2.273(3) ˚
Ain
1b, we e as expec ed and un ema kable when compa ed o
hose obse ed o [Ag(py idine)
2
]PF
6
(2.129(6) ˚
A) and
[I(py idine)
2
]PF
6
(2.268(2) ˚
A),
24,25
o e en he mo e closely
ela ed 2-e hylpy idine (2-E py) de i a i es [Ag(2-E py)
2
]PF
6
(2.128(3)/2.130(3) ˚
A) and [I(2-E py)
2
]PF
6
(2.270(2) ˚
A),
13
wi h only
he sil e (I) compa isons being sligh ly beyond a 3s ole ance
and he e o e c ys allog aphically dis inguishable om one
ano he . I should be no ed ha he p e iously epo ed [I(2-
E py)
2
]PF
6
adop ed a coun e in ui i e syn-congu a ion o he 2-
e hyl subs i uen s, wi h concomi an loss o co-plana i y (an
angle o 32.4be ween he planes o he wo py idyl ings was
ound). Howe e , in bo h 1a and 1b, he ligands we e co-plana
and, as expec ed, assumed an i-congu a ions (Fig. 2) due o
s e ic conside a ions, wi h one o he wo pendan phenyl ings
poin ing di ec ly away om he Ag
+
o I
+
cen es, espec i ely.
In e es ingly, he I
+
cen e o 1b is no iceably exe ing an
inc eased epulsion on he 2-subs i uen s, despi e he ligands
being u he apa om one ano he and he I
+
when compa ed
Fig. 1 The supe imposed 1H NMR spec a o 1( ed), 1a (g een), and 1b
(blue) o hei non-o e lapping py idyl and me hine esonances in
CD
2
Cl
2
(500 MHz, 298 K).
Fig. 2 The X- ay c ys al s uc u es o he ca ions o [1–Ag–1]PF
6
(1a;
le ) and [1–I–1]PF
6
(1b; igh ) showing he an i-configu a ion o he
ligands due o s e ic conside a ions (PF
6
anions omi ed o cla i y;
he mal ellipsoids a 50% p obabili y).
‡The
1
H NMR spec um was collec ed wi hin 5 minu es o I
2
addi ion, bu
a sa is ac o y
1
H–
15
N HMBC expe imen ook se e al hou s o comple e o gi e
he chemical shis a ed.
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o he Ag
+
in 1a. This dis o ion is no eadily appa en in he
p e iously discussed bond leng hs o angles, bu can be quan-
ied by compa ison o he I
+
/py idyl(C2)/I
+
/py idyl(C6)
h ough-space dis ances in 1b o 3.074(5)/3.252(4) ˚
A, which a e
eminiscen o hose obse ed o [I(2-E py)
2
]PF
6
o 3.086(2)/
3.244(2) ˚
A, and a e clea ly de ia ing om he mo e alike pai
o dis ances o Ag
+
/py idyl(C2)/Ag
+
/py idyl(C6) in 1a o
3.065(2)/3.070(2) ˚
A and 3.050(3)/3.085(2) ˚
A. Whils a ew exam-
ples o disc e e sil e (I) complexes ha e been epo ed wi h
simila ly s e ically bulky 2-subs i u ed py idines,
17,26
hough all
less s e ically encumbe ed han 1a and 2a, no examples o such
s e ically endowed iodine(I) complexes cu en ly exis in he
li e a u e.
The solid-s a e s uc u e o 2a (Fig. 3) e ealed signican ly
leng hened Ag–N bond leng hs o 2.210(2) and 2.210(2) ˚
A, which
a e, as bes as can be de e mined,
17
some o he longes known
o da e o a disc e e, linea sil e (I) complex inco po a ing 2-
subs i u ed py idines, only i alled by hose o [Ag(4-(phenyl-
e hynyl)py idine)
2
]
+
(2.214(5) and 2.217(5) ˚
A).
27
Whils longe
Ag–N bond leng hs a e p esen in he li e a u e, in hose
ins ances he elonga ion can be associa ed o he complexes
exhibi ing signican ly dis o ed N–Ag–N angles due o pa ial
coo dina ion om ano he dono o he sil e (I) cen e, such as
coo dina ion om an anion,
28,29
o om s ain caused by he
ligand sys em due o i being dime ic/polyme ic in na u e,
30
o
bo h.
31
Unlike in 1a and 1b, he py idyl ligands in 2a a e no co-
plana , no do hey assume an an i-congu a ion, wi h a N–Ag–
N angle o 173.04(7)and an angle o 78.4be ween he planes
o he wo py idyl ings. I he de ia ion om linea i y o he
N–I–N angle in 2b was simila o ha obse ed o 2a, hen his
could con ibu e o he high eac i i y o 2b, gi en ha he
la ges obse ed de ia ion om linea i y o an iodine(I)
complex is o [I(2-E py)
2
]PF
6
wi h a N–I–N angle o
173.62(10).
13
Whils an inc ease in eac i i y o 2b was an icipa ed ela-
i e o 1b due o he sligh ly inc eased s e ic bulk o i s
subs i uen , he apid decomposi ion o 2b was pa icula ly
s iking in compa ison o he only minimal decomposi ion ha
was obse ed ae 8 days o a sample o 1b kep in solu ion o
he du a ion. The pe sis ence o 1b is d as ically longe han o
many o he known iodine(I) complexes inco po a ing Lewis
bases wi h s e ically negligible subs i uen s in he 2-posi ions,
such as 2-e hylpy idine and 1-e hylpipe idine,
14
bo h o which
demons a ed beha iou esembling ha o 2b.§.
Compu a ional s udies
DFT calcula ions (M06-2X/de 2-TZVP le el o heo y, see ESI†
and heo e ical me hods below o de ails) we e pe o med o
in es iga e he coun e in ui i e syn-congu a ion o 2a and also
o cha ac e ise compu a ionally he elusi e 2b s uc u e ha
could no be s uc u ally cha ac e ised by X- ay diff ac ion
me hods. Fig. 4 shows he op imised s uc u e o 2a and he
hypo he ical an i-congu a ion (deno ed as 2a0), ha exhibi s
a pe ec ly linea N–Ag–N angle and co-plana py idyl ings. This
congu a ion is 2.3 kcal mol
1
less s able han he syn-cong-
u a ion, in line wi h he expe imen al obse a ion.
The DFT op imised s uc u e exhibi s a N–Ag–N angle o 172
and angle be ween he py idyl ings o 81, in good ag eemen
wi h he expe imen al alues (c . 173and 78, espec i ely).
Simila ag eemen , including dis ances, was obse ed o he
es o complexes (see ESI, Table S2†), hus gi ing eliabili y o
his le el o heo y. The la ge s abili y o he syn-congu a ion
in 2a is mos likely due o he con ibu ion o an de Waals
in e ac ions be ween he me hyl g oups and he a oma ic ings,
as e ealed by he nonco alen in e ac ion plo analysis (NCI-
Plo index, see Fig. S43 in he ESI†).
The geome ies o he syn- and an i-congu a ions o
compound 2b we e also calcula ed (Fig. 5). The calcula ions
e eal ha bo h isome s a e p ac ically isoene ge ic ( he syn-
congu a ion is only 0.2 kcal mol
1
mo e s able). A likely
explana ion is ha he s abilisa ion due o he co-plana i y o
he ings in he an i-congu a ion is mo e impo an in he
iodine(I) complex 2b han in he sil e (I) complex 2a. In ac , he
Fig. 3 The X- ay c ys al s uc u e o he ca ion o [2–Ag–2]PF
6
(2a)
(PF
6
anion omi ed o cla i y; he mal ellipsoids a 50% p obabili y).
Fig. 4 M06-2X/de 2-TZVP op imised geome ies o he syn (a) and
an i (b) configu a ions o he ca ion o 2a, wi h indica ion o he ela i e
ene gy. The me hyl g oups a e ep esen ed in ed.
§Despi e decomposi ion o [I(2-E py)
2
]PF
6
being obse ed wi hin minu es o i s
syn hesis by NMR s udies, i was obus enough o i s solid-s a e s uc u e o
be ob ained.
13
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an i-congu a ion acili a es he back-dona ion om he iodine
a om ( ee lone pai ) o he p-sys em, which is impo an in
iodine(I) complexes.
14
This effec compensa es o he an de
Waals in e ac ions ha a e es ablished in he syn-congu a ion,
which a e also less impo an in 2b, as e ealed by he NCIPlo
index (Fig. S43†). The geome ies o he Ag
+
and I
+
compounds
(2a and 2b) in he an i-congu a ion a e e y simila . In
con as , hose in he syn-congu a ion (2a0and 2b0) a e mo e
diffe en , especially ega ding he py idyl ing plane angles ha
diffe by 21(c . 60in 2b0and 81in 2a0).
Finally, he dissocia ion ene gies (measu ed as [L–I–L]
+
o I
+
+ 2L; E
dis
) and I–N dis ances o he iodine(I) complexes 1b and
2b we e compa ed wi h p e iously epo ed examples ins ead
inco po a ing he quinuclidine (quin) and dime hylaminopy -
idine (DMAP) ligands (Table 1).
14
The esul s show he g ea es
s abili y o he [I(quin)
2
]
+
and [I(DMAP)
2
]
+
complexes ollowed
by 1b and 2b in line wi h he I–N dis ances ha a e signican ly
longe in he la e complexes. The lowes dissocia ion ene gy
co esponds o compound 2b, which ag ees wi h i s highe
eac i i y as obse ed in he NMR expe imen s.
Anion and packing effec s
In halogen(I) chemis y, he BF
4
and PF
6
anions a e adi ionally
used owing o hei weakly coo dina ing na u e, which he e o e
do no complica e he well-es ablished Ag
+
o X
+
(X ¼B , I)
ca ion exchange p ocess used o syn hesise halogen(I)
complexes. In he solid s a e, bo h he sil e (I) complexes 1a and
2a showed meaning ul in e ac ions wi h hei espec i e PF
6
anions, hough wi h 2a as a disc e e ion pai and 1a as
a con inuous 1D a ay o Ag
+
/F–PF
4
–F/Ag
+
/F–PF
4
–F
con ac s (Fig. 6). The closes Ag
+
/F dis ances o 2.918(2)/
2.990(2) ˚
A o he wo independen molecules in 1a we e
below he combined an de Waals adii o o hese a oms (Ag +
F¼3.19 ˚
A), hough a e compa able o o he p e iously epo ed
linea sil e (I) complexes, such as [Ag(2-E py)
2
]PF
6
and
[Ag(DMAP)
2
]PF
6
.
12,13
Simila ly, 1a was able o success ully syn-
hesise 1b ia ca ion exchange, jus as has been epo ed o he
a o emen ioned li e a u e complexes. Howe e , he closes
Ag
+
/F dis ance o 2.810(1) ˚
Ain2a is signican ly sho e han
hose obse ed in 1a, and is eminiscen o sil e (I) complexes
wi h mo e s ongly coo dina ing anions, such as hose bea ing
po en ial oxygen dono s like he ni a e anion. The mo e
s ongly bound PF
6
anion in 2a is likely an ou come o he
s e ically bulky ligands p e en ing op imal elec onic s abilisa-
ion o he Ag
+
cen e, which was simila ly indica ed by he
long Ag–N bond leng hs obse ed in 2a ( ide sup a).
Wi h espec o 1b, simila o 2a, i also exis ed as a disc e e
ion pai . P e ious s udies ha e con med ha iodine(I) ions
in insically impose a linea 2-coo dina ion sphe e, and unlike
hei sil e (I) coun e pa s, a e insensi i e o he iden i y o he
anion p esen .
25
This is appa en in 1b wi h a pai o sho es
I
+
/F dis ances o 3.618(5), which we e eminiscen o hose
obse ed in [I(2-E py)
2
]PF
6
(sho es I
+
/F dis ances ¼3.693(2)
˚
A),
13
bo h o which we e well o e he combined an de Waals
adii o hese a oms (c . an de Waals adii o I + F ¼3.45 ˚
A),
indica ing ha nei he we e meaning ul in e ac ions.
In igued by he inuence o he anions on he sil e (I)
p ecu so s, he BF
4
,[1–Ag–1]BF
4
(1e) and [2–Ag–2]BF
4
(2e), and
OT , [1–Ag–1]OT (1 ; OT ¼ ia e) and [2–Ag–2]OT (2 ), anion
analogues we e also p epa ed and c ys allised so compa isons
could be made (Fig. 7). These anions we e selec ed as hey a e
commonly used in he p epa a ion o halogen(I) complexes, so
we e mo e ele an han anions such as ni a e, and sa e han
o he s such as he pe chlo a e anion. Bo h 1e and 2e exis as
disc e e ion pai s wi h he BF
4
anions, wi h he sho es Ag
+
/F
Fig. 5 M06-2X/de 2-TZVP op imised geome ies o he syn (a) and
an i (b) configu a ions o he ca ion o 2b, wi h indica ion o he ela i e
ene gy. The me hyl g oups a e ep esen ed in ed.
Table 1 Dissocia ion ene gies (E
dis
, kcal mol
1
), I–N dis ances (d,˚
A)
and N–I–N angles (a,) a he M062X/de 2-TZVP le el o heo y
1b 2b(syn)2b (an i) [I(quin)
2
]
+
[I(DMAP)
2
]
+
E
dis
126.8 119.8 119.6 179.7 181.8
d2.273 2.305 2.301 2.288 2.245
a180 173.8 180 180 180
Fig. 6 The packing o h ee molecules o 1a showing he 1D ne wo k
o sho Ag
+
–F in e molecula in e ac ions (all dis ances in ˚
A; ligands
simplified o cla i y).
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dis ances o 2.828(5)/2.965(8) ˚
A ( he BF
4
anion was ound o
equally occupy wo posi ions in he solid s a e) and 2.743(2) ˚
A,
espec i ely. As expec ed, he OT anion complexes 1 and 2
we e obse ed as neu al T-shaped species, wi h he OT anion
bound o he Ag
+
cen es wi h Ag
+
–O bond leng hs o 2.685(2)
and 2.578(2) ˚
A, espec i ely. These ma ched epo ed examples
o OT sil e (I) complexes inco po a ing 2-subs i u ed py idines
in he li e a u e, [Ag(2-me hoxypy idine)
2
]OT and [Ag(2-
me hylsul anylpy idine)
2
]OT ,
32,33
which demons a ed he
same T-shaped geome y and simila Ag
+
–O bond leng hs o
2.679(3) and 2.673(3) ˚
A (mino posi ion (19%) o he diso de ed
OT anion igno ed), espec i ely.
These solid-s a e obse a ions we e eec ed in he solu ion-
s a e s udies o he
1
H–
15
N HMBC de e mined
15
N NMR
chemical shis (Table 2). The alues show ha he compa isons
o he BF
4
(1e and 2e) and PF
6
(1a and 2a) complexes only
exhibi negligible diffe ences o he same ligand (1a s. 1e and
2a s. 2e), whils he OT complexes showed small, bu signi-
can , diffe ences o 4.1 (1a s. 1 ) and 1.4 (2a s. 2 ) ppm when
compa ed o hei PF
6
analogues, possibly indica ing ha he
less s e ically encumbe ed complex 1 con inues o in e ac wi h
he OT anion in solu ion, a leas mo e so han 2 .
A common ea u e o all sil e complexes is ha he anion is
close o he Ag(I) a om, es ablishing semi-coo dina ion bonds,
o coinage bonds (CiB) acco ding o he nomencla u e p oposed
by some au ho s.
34,35
These con ac s likely inuence he Ag–N
dis ance along wi h he bulkiness o he ligands. The CiBs in
complexes 1a, e, and 2a, e, we e analysed using he quan um
heo y o a oms-in-molecules (QTAIM).
36
Fig. 8 shows he
QTAIM ep esen a ion o he six compounds showing in all
cases a bond c i ical poin (CP, ep esen ed as ed sphe e) and
bond pa h (o ange line) connec ing one a om o he anion o he
sil e a om, hus con ming he exis ence o he in e ac ion. In
all cases bo h he Laplacian (V
2
) o he elec on densi y and he
o al ene gy densi y (H
) a he bond CP a e posi i e, hus
e ealing ha he Ag/F(O) con ac s a e nonco alen in na u e
(CiBs). This is co obo a ed by he small alues o (see
Table 3), con ming he weak and closed shell na u e o he
CiBs. The s eng h o hese CiBs was es ima ed by using he
o al ene gy densi y a he bond CP and he equa ion p oposed
by Espinosa e al.
37
This me hod is con enien o e alua e he
nonco alen in e ac ion wi hou he con ibu ion o he pu e
coulombic a ac ion be ween he coun e ions. These alues a e
indica ed in Fig. 8 (anno a ed in ed close o he CPs). The
ene gies ange om 2.3 kcal mol
1
in 1a o 9.5 kcal mol
1
in 2 ,
in line wi h he Ag/anion dis ances (see Table 3). I is in e -
es ing o highligh ha o he complexes wi h he sho es Ag/
anion dis ance o each se ies (complexes 1 and 2 ) he densi y
( , see Table 3) a he bond CP is g ea e han ha in he es o
Fig. 7 The X- ay c ys al s uc u es o [1–Ag–1]OT (1 ; le ) and [2–
Ag–2]OT (2 ; igh ) showing he bound OT anions (py idyl subs i u-
en s simplified o cla i y; he mal ellipsoids a 50% p obabili y).
Table 2 The
1
H–
15
N HMBC de e mined
15
N NMR chemical shi s
(ppm) o he sil e (I) complexes [1–Ag–1]
+
and [2–Ag–2]
+
wi h
diffe en anions (BF
4
,PF
6
, and OT )
Complex d
N
Complex d
N
[1–Ag–1]PF
6
(1a)–118.6 [2–Ag–2]PF
6
(2a)–111.4
[1–Ag–1]BF
4
(1e)–117.6 [2–Ag–2]BF
4
(2e)–111.9
[1–Ag–1]OT (1 )–114.5 [2–Ag–2]OT (2 )–110.0
Fig. 8 QTAIM analysis (only he Ag/anion con ac is ep esen ed o
cla i y) o compounds 1a (a), 2a (b), 1e (c), 2e (d), 1 (e) and 2 ( ). The
dissocia ion ene gies a e indica ed in ed adjacen o he bond CPs
( ed sphe es).
Table 3 The X- ay Ag–N and Ag/X(X¼F, O) dis ances, densi y ( ,
a.u.) a he bond CPs ep esen ed in Fig. 8 and Wibe g bond indexes
(WBI) o all he sil e (I) complexes syn hesised in his wo k
Complex Ag–NAg–X 10
2
WBI (Ag–N)
1a 2.151 2.990 0.97 0.164 & 0.159
1e 2.150 & 2.155 2.828 1.46 0.144 & 0.150
1 2.170 & 2.175 2.685 2.23 0.138 & 0.133
2a 2.210 2.818 1.45 0.092 & 0.095
2e 2.215 & 2.219 2.743 1.75 0.081 & 0.091
2 2.224 & 2.223 2.578 2.67 0.080 & 0.082
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complexes, hus sugges ing a g ea e cha ge ans e om he
anion o he Ag(I), hus causing he elonga ion and weakening
o he N–Ag–N bonds, as e idenced by he longe Ag–N
dis ances and smalle Wibe g bond indexes (see Table 3)
38
in
complexes 1 and 2 .
Conclusions
In conclusion, sil e (I) and iodine(I) complexes o s e ically
bulky 2-subs i u ed py idines we e syn hesised and spec o-
scopically cha ac e ised o in es iga e he s e ic limi a ions o
iodine(I) ion o ma ion. Th ee o hese complexes, including
wo sil e (I) and one iodine(I) complex, we e also deni i ely
con med by X- ay diff ac ion s udies, hus demons a ing he
possibili y o o m iodine(I) complexes wi h s e ically bulky
ligands in close p oximi y o he I
+
cen e. The effec o he
anions on he s e ically bulky sil e (I) complexes was examined
and u he explo ed wi h a ange o diffe en anions,
commonly used in halogen(I) chemis y, h ough ex ensi e DFT
s udies. DFT calcula ions we e u ilised o explain he o ma ion
o he syn-isome o 2a, as well as o s udy he dec eased s abili y
o 2b wi h espec o 1b and o he iodine(I) complexes epo ed
in he li e a u e, highligh ing he po en ial o s e ic con ol in
u u e halogen(I) chemis y.
Expe imen al
Gene al conside a ions
All eagen s and sol en s we e ob ained om comme cial
supplie s and used wi hou u he pu ica ion, excep o 2-
(diphenylme hyl)py idine (1) and 2-(1,1-diphenyle hyl)py idine
(2) which we e syn hesised acco ding o li e a u e p oce-
du es.
39,40
Fo s uc u al NMR assignmen s,
1
H NMR and
1
H–
15
N NMR co ela ion spec a we e eco ded on a B uke
A ance III 500 MHz spec ome e a 25 CinCD
2
Cl
2
. Chemical
shis a e epo ed on he dscale in ppm using he esidual
sol en signal as in e nal s anda d (CH
2
Cl
2
in CD
2
Cl
2
:d
H
5.32),
o o
1
H–
15
N NMR spec oscopy, o an ex e nal d
3
-MeNO
2
s anda d. Fo he
1
H NMR spec oscopy, each esonance was
assigned acco ding o he ollowing con en ions: chemical shi
(d) measu ed in ppm, obse ed mul iplici y, obse ed coupling
cons an (JHz), and numbe o hyd ogen a oms. Mul iplici ies
a e deno ed as: s (single ), d (double ), ( iple ), m (mul iple ),
and b (b oad). Fo he
1
H–
15
N HMBC spec oscopy, spec al
windows o 4 ppm (
1
H) and 300 ppm (
15
N) we e used, wi h 1024
poin s in he di ec dimension and 512 inc emen s used in he
indi ec dimension, wi h subsequen peak shape analysis being
pe o med o gi e he epo ed
15
N NMR esonances.
The single c ys al X- ay da a o 1c was collec ed a 120 K
using an Agilen Supe No a dual wa eleng h diff ac ome e
wi h an A las de ec o using mi o -monoch oma ed Cu-Ka(l¼
1.54184 ˚
A) adia ion. The single c ys al X- ay da a o 1a,1b and
2a was collec ed a 120 K using an Agilen Supe No a diff ac-
ome e wi h an Eos de ec o using mi o -monoch oma ed Mo-
Ka(l¼0.71073 ˚
A) adia ion The p og am C ysAlisP o
41
was
used o he da a collec ion and educ ion on he Supe No a
diff ac ome e , and he in ensi ies we e abso p ion co ec ed
using a Gaussian ace index abso p ion co ec ion me hod. All
s uc u es we e sol ed by in insic phasing (SHELXT)
42
and
ened by ull-ma ix leas squa es on F
2
using he OLEX2,
43
u ilizing he SHELXL-2015 module.
44
Aniso opic displacemen
pa ame e s we e assigned o non-H a oms and iso opic
displacemen pa ame e s o all H a oms we e cons ained o
mul iples o he equi alen displacemen pa ame e s o hei
pa en a oms wi h U
iso
(H) ¼1.2 U
eq
(a oma ic) o U
iso
(H) ¼1.5
U
eq
(alkyl) o hei espec i e pa en a oms. The X- ay single
c ys al da a and CCDC numbe s o all new s uc u es a e
included below.
Syn hesis and cha ac e isa ion
All sil e (I) and iodine(I) complexes we e p epa ed using he
same quan i a i e gene al me hods, which a e gi en below
using [1–Ag–1]PF
6
(1a) and [1–I–1]PF
6
(1b) as examples.
F ee ligand 2-(diphenylme hyl)py idine (1).
1
H NMR (500
MHz, CD
2
Cl
2
)d8.56 (d, J¼4.0 Hz, 1H), 7.62 ( d, J¼7.7, 1.7 Hz,
1H), 7.30 ( , J¼7.4 Hz, 4H), 7.23 (d, J¼7.3 Hz, 2H), 7.19 (d, J¼
7.2 Hz, 4H), 7.17–7.11 (m, 2H), 5.65 (s, 1H);
15
N NMR (500 MHz,
CD
3
CN) d65.4. The solid-s a e s uc u e is known.
45
Syn hesis o [1–Ag–1]PF
6
(1a). A DCM (3 mL) solu ion o 1
(24.5 mg, 0.1 mmol) was added o AgPF
6
(12.6 mg, 0.05 mmol)
and he esul ing colou less solu ion s i ed o 1.5 hou s. All
ola iles emo ed unde educed p essu e o lea e a whi e solid.
1
H NMR (500 MHz, CD
2
Cl
2
)d8.00 (d, J¼4.5 Hz, 1H), 7.87 ( d, J
¼7.9, 1.6 Hz, 1H), 7.39–7.33 (m, 7H), 7.17 (d, J¼8.0 Hz, 1H),
7.05 (d, J¼6.7 Hz, 4H), 5.47 (s, 1H);
15
N NMR (500 MHz, CD
3
CN)
d118.6. C ys als sui able o single c ys al X- ay diff ac ion
we e ob ained om a DCM solu ion o 1a apou diffused wi h
DIPE. C ys al da a o 1a: CCDC-2144042, [C
36
H
30
AgN
2
]PF
6
,M¼
743.46, colou less pla e, 0.08 0.19 0.29 mm
3
, iclinic,
space g oup P
1 (No. 2), a¼8.5415(3) ˚
A, b¼11.2632(6) ˚
A, c¼
16.8492(7) ˚
A, a¼91.301(4),b¼97.022(3),g¼101.834(4),V¼
1572.71(12) ˚
A
3
,Z¼2, D
calc
¼1.570 g cm
3
,F(000) ¼752, m¼
0.76 mm
1
,T¼120.0(1) K, q
max
¼29.2, 7314 o al eec ions,
5852 wi h I
o
>2s(I
o
), R
in
¼0.028, 7314 da a, 461 pa ame e s,
186 es ain s, GooF ¼1.06, 0.57 < dD <0.55 e˚
A
3
,R[F
2
>
2s(F
2
)] ¼0.036, wR(F
2
)¼0.079.
Syn hesis o [1–I–1]PF
6
(1b). ACD
2
Cl
2
(0.5 mL) solu ion o 1
(9.8 mg, 0.04 mmol) was added o AgPF
6
(5.1 mg, 0.02 mmol)
and he esul ing colou less solu ion s i ed o 1.5 hou s. I
2
(5.1 mg, 0.02 mmol) was added as a solid and he mix u e
sonica ed o 1 minu e o gi e a ed solu ion and a yellow
p ecipi a e, which was used as is o NMR spec oscopic s udies.
1
H NMR (500 MHz, CD
2
Cl
2
)d8.84 (d, J¼4.8 Hz, 1H), 8.06 ( d, J
¼7.8, 1.3 Hz, 1H), 7.42–7.31 (m, 7H), 7.23 (d, J¼7.8 Hz, 1H),
6.99 (d, J¼6.6 Hz, 4H), 5.82 (s, 1H);
15
N NMR (500 MHz, CD
3
CN)
d165.7. C ys als sui able o single c ys al X- ay diff ac ion
we e ob ained by e apo a ion o a DCM : pen ane (1 : 3) solu-
ion o 1b. C ys al da a o 1b: CCDC-2144043, [C
36
H
30
IN
2
]PF
6
,
M¼762.49, colou less pla e, 0.04 0.10 0.23 mm
3
, mono-
clinic, space g oup C2/c,a¼20.8912(5) ˚
A, b¼8.1839(2) ˚
A, c¼
18.9412(7) ˚
A, b¼94.605(3),V¼3227.95(16) ˚
A
3
,Z¼4, D
calc
¼
1.569 g cm
3
,F(000) ¼1528, m¼1.11 mm
1
,T¼120.0(1) K,
q
max
¼28.0, 3844 o al eec ions, 2994 wi h I
o
>2s(I
o
), R
in
¼
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0.043, 3844 da a, 230 pa ame e s, 51 es ain s, GooF ¼1.09,
0.74 < dD <0.75 e˚
A
3
,R[F
2
>2s(F
2
)] ¼0.046, wR(F
2
)¼0.100.
Syn hesis o [H(1)]PF
6
(1c). A MeOH (5 mL) solu ion o 1
(159.4 mg, 0.65 mmol) was dilu ed wi h H
2
O (1 mL), hen conc.
HCl (0.1 mL, excess) was added. Ae 5 minu es o s i ing,
[NH
4
]PF
6
(158.9 mg, 0.975 mmol) was added and s i ed o
a u he 5 minu es. The o al olume was educed unde
educed p essu e o app oxima ely hal , a which ime a whi e
p ecipi a e was obse ed. Addi ion H
2
O (7 mL) was added o
induce u he p ecipi a ion, and he whi e solid collec ed by
l a ion (N. B. he d ied p ecipi a e was e y s a ic p one).
Reco e ed yield ¼0.150 mg (0.38 mmol, 59%).
1
H NMR (500
MHz, CD
2
Cl
2
)d12.27 (s.b , 1H), 8.37 (d, J¼5.5 Hz, 1H), 8.34 ( d,
J¼8.0, 1.3 Hz, 1H), 7.77 ( , J¼6.4 Hz, 1H), 7.56 (d, J¼8.1 Hz,
1H), 7.43–7.31 (m, 6H), 7.12 (d, J¼7.0 Hz, 4H), 5.91 (s, 1H);
15
N
NMR (500 MHz, CD
3
CN) d167.5. C ys als sui able o single
c ys al X- ay diff ac ion we e ob ained om a DCM solu ion o
1c apou diffused wi h pen ane. C ys al da a o 1c: CCDC-
2144044, [C
18
H
16
N]PF
6
,M¼391.29, colou less pla e, 0.05
0.16 0.25 mm
3
, monoclinic, space g oup P2
1
/c,a¼11.5946(3)
˚
A, b¼19.6879(4) ˚
A, c¼15.0819(4) ˚
A, b¼100.548(2),V¼
3384.62(14) ˚
A
3
,Z¼8, D
calc
¼1.536 g cm
3
,F(000) ¼1600, m¼
2.05 mm
1
,T¼120.0(1) K, q
max
¼76.6, 6629 o al eec ions,
5486 wi h I
o
>2s(I
o
), R
in
¼0.032, 6629 da a, 475 pa ame e s, no
es ain s, GooF ¼1.08, 0.66 < dD <0.25 e˚
A
3
,R[F
2
>2s(F
2
)]
¼0.052, wR(F
2
)¼0.145.
Syn hesis o [1–H–1]PF
6
(1d). ACD
2
Cl
2
(0.5 mL) solu ion o 1
(4.9 mg, 0.02 mmol) was added o 1c (7.8 mg, 0.02 mmol), and he
esul ing colou less solu ion s i ed o 15 minu es be o e being
used o NMR spec oscopic s udies.
1
H NMR (500 MHz, CD
2
Cl
2
)
d8.21 (d, J¼4.4 Hz, 1H), 8.00 ( d, J¼7.8, 1.6 Hz, 1H), 7.46 ( , J¼
5.7 Hz, 1H), 7.39–7.26 (m, 7H), 7.10 (d, J¼7.1 Hz, 4H), 5.96 (s.b ,
0.5H), 5.67 (s, 1H);
15
N NMR (500 MHz, CD
3
CN) d122.5.
Syn hesis o [1–Ag–1]BF
4
(1e). P epa ed analogously o 1a
using AgBF
4
(9.7 mg, 0.05 mmol).
1
H NMR (500 MHz, CD
2
Cl
2
)
d8.09 (d, J¼4.5 Hz, 2H), 7.85 ( d, J¼7.9, 1.5 Hz, 2H), 7.39–7.31
(m, 14H), 7.14 (d, J¼8.0 Hz, 2H), 7.06 (d, J¼7.1 Hz, 8H), 5.51 (s,
2H);
15
N NMR (500 MHz, CD
3
CN) d117.6. C ys als sui able o
single c ys al X- ay diff ac ion we e ob ained om a DCM
solu ion o 1e apou diffused wi h pen ane. C ys al da a o 1e:
CCDC-2150094, [C
36
H
30
AgN
2
]BF
4
$2(CH
2
Cl
2
), M¼855.15, col-
ou less pla e, 0.15 0.38 0.52 mm
3
, monoclinic, space g oup
P2
1
,a¼9.5033(4) ˚
A, b¼15.3402(6) ˚
A, c¼13.3461(5) ˚
A, b¼
108.197(4),V¼1848.32(13) ˚
A
3
,Z¼2, D
calc
¼1.537 g cm
3
,
F(000) ¼864, m¼0.89 mm
1
,T¼120.0(1) K, q
max
¼27.8, 7174
o al eec ions, 6559 wi h I
o
>2s(I
o
), R
in
¼0.032, 7174 da a,
516 pa ame e s, 95 es ain s, GooF ¼1.08, 0.59 < dD <0.92
e˚
A
3
,R[F
2
>2s(F
2
)] ¼0.037, wR(F
2
)¼0.100.
Syn hesis o [1–Ag–1]OT (1 ). P epa ed analogously o 1a
using AgOT (12.8 mg, 0.05 mmol).
1
H NMR (500 MHz, CD
2
Cl
2
)
d8.17 (d, J¼4.4 Hz, 2H), 7.81 ( d, J¼7.8, 1.6 Hz, 2H), 7.38–7.28
(m, 14H), 7.10–7.04 (m, 10H), 5.56 (s, 2H);
15
N NMR (500 MHz,
CD
3
CN) d114.5. C ys als sui able o single c ys al X- ay
diff ac ion we e ob ained om a DCM solu ion o 1 apou
diffused wi h E
2
O. C ys al da a o 1 : CCDC-2150095,
[C
36
H
30
AgN
2
][CF
3
O
3
S], M¼747.56, colou less block, 0.21
0.40 0.44 mm
3
, iclinic, space g oup P
1 (No. 2), a¼
11.3073(5) ˚
A, b¼11.6452(4) ˚
A, c¼15.0627(7) ˚
A, a¼68.117(4),
b¼85.174(4),g¼71.906(4),V¼1748.34(14) ˚
A
3
,Z¼2, D
calc
¼
1.420 g cm
3
,F(000) ¼760, m¼0.69 mm
1
,T¼120.0(1) K, q
max
¼29.2, 8052 o al eec ions, 6904 wi h I
o
>2s(I
o
), R
in
¼0.029,
8052 da a, 424 pa ame e s, no es ain s, GooF ¼1.05, 0.44 <
dD <0.54 e˚
A
3
,R[F
2
>2s(F
2
)] ¼0.033, wR(F
2
)¼0.077.
F ee ligand 2-(1,1-diphenyle hyl)py idine (2).
1
H NMR (500
MHz, CD
2
Cl
2
)d8.58 (d , J¼3.8, 0.8 Hz, 1H), 7.57 ( d, J¼7.9,
1.9 Hz, 1H), 7.27 ( , J¼7.4 Hz, 4H), 7.21 ( , J¼7.2 Hz, 2H), 7.15–
7.08 (m, 5H), 7.03 (d, J¼8.0 Hz, 1H), 2.20 (s, 3H);
15
N NMR (500
MHz, CD
3
CN) d65.1.
Syn hesis o [2–Ag–2]PF
6
(2a). P epa ed analogously o 1a
using 2(25.9 mg, 0.1 mmol).
1
H NMR (500 MHz, CD
2
Cl
2
)d7.89
( d, J¼8.1, 1.7 Hz, 1H), 7.68 (d, J¼4.9 Hz, 1H), 7.50 (d, J¼
8.1 Hz, 1H), 7.36–7.28 (m, 7H), 7.02 (d, J¼7.0 Hz, 4H), 2.12 (s,
3H);
15
N NMR (500 MHz, CD
3
CN) d111.4. C ys als sui able o
single c ys al X- ay diff ac ion we e ob ained om a DCM
solu ion o 2a apou diffused wi h DIPE. C ys al da a o 2a:
CCDC-2144045, [C
38
H
34
AgN
2
]PF
6
,M¼771.51, colou less block,
0.13 0.20 0.37 mm
3
, monoclinic, space g oup I2/a,a¼
19.5839(3) ˚
A, b¼9.2056(1) ˚
A, c¼36.7734(5) ˚
A, b¼97.273(1),V
¼6576.23(15) ˚
A
3
,Z¼8, D
calc
¼1.558 g cm
3
,F(000) ¼3136, m¼
0.73 mm
1
,T¼120.0(1) K, q
max
¼28.8, 7810 o al eec ions,
6708 wi h I
o
>2s(I
o
), R
in
¼0.030, 7810 da a, 435 pa ame e s, no
es ain s, GooF ¼1.04, 0.38 < dD <0.39 e˚
A
3
,R[F
2
>2s(F
2
)]
¼0.033, wR(F
2
)¼0.070.
A emp ed syn hesis o [2–I–2]PF
6
(2b). P epa ed analo-
gously o 1b using 2(10.4 mg, 0.04 mmol).
1
H NMR (500 MHz,
CD
2
Cl
2
)d8.23 (s.b , 1H), 7.96 ( d, J¼7.7, 0.9 Hz, 1H), 7.43 (d, J
¼7.6 Hz, 2H), 7.36–7.28 (m, 7.0 Hz, 6H), 7.05 (d, J¼7.2 Hz, 4H),
2.22 (s, 3H);
15
N NMR (500 MHz, CD
3
CN) d121.5 (decompo-
si ion p oduc ).
Syn hesis o [H(2)]PF
6
(2c). A MeOH (5 mL) solu ion o 2
(168.6 mg, 0.65 mmol) was dilu ed wi h H
2
O (1 mL), hen conc.
HCl (0.1 mL, excess) was added. Ae 5 minu es o s i ing,
[NH
4
]PF
6
(158.9 mg, 0.975 mmol) was added and s i ed o
a u he 5 minu es. The o al olume was educed unde
educed p essu e o app oxima ely hal , a which ime a whi e
p ecipi a e was obse ed. Addi ion H
2
O (7 mL) was added o
induce u he p ecipi a ion, and he whi e solid collec ed by
l a ion. P oduc was ini ially obse ed as a colou less oil,
which solidied ae se e al hou s. Reco e ed yield ¼91.6 mg
(0.23 mmol, 35%).
1
H NMR (500 MHz, CD
2
Cl
2
)d9.12 (s. e y b ,
1H), 8.74 (dd, J¼5.8, 0.9 Hz, 1H), 8.42 ( d, J¼8.1, 1.5 Hz, 1H),
7.86 (dd, J¼6.3, 1.0 Hz, 1H), 7.70 (d, J¼8.2 Hz, 1H), 7.43–7.36
(m, 6H), 7.08 (dd, J¼8.0, 1.3 Hz, 4H), 2.39 (s, 3H);
15
N NMR (500
MHz, CD
3
CN) d180.4.
Syn hesis o [2–H–2]PF
6
(2d). ACD
2
Cl
2
(0.5 mL) solu ion o 2
(5.2 mg, 0.02 mmol) was added o 2c (8.1 mg, 0.02 mmol), and
he esul ing colou less solu ion s i ed o 15 minu es be o e
being used o NMR spec oscopic s udies.
1
H NMR (500 MHz,
CD
2
Cl
2
)d9.86 (s.b , 0.5H), 8.59 (d, J¼4.4 Hz, 1H), 7.98 ( d, J¼
8.0, 1.6 Hz, 1H), 7.44 (dd, J¼5.6, 0.8 Hz, 1H), 7.39–7.24 (m, 7H),
7.08 (d, J¼7.2 Hz, 4H), 2.28 (s, 3H);
15
N NMR (500 MHz, CD
3
CN)
d123.0.
Syn hesis o [2–Ag–2]BF
4
(2e). P epa ed analogously o 1a
using 2(25.9 mg, 0.1 mmol) and AgBF
4
(9.7 mg, 0.05 mmol).
1
H
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NMR (500 MHz, CD
2
Cl
2
)d7.90 ( d, J¼8.1, 1.7 Hz, 2H), 7.69 (d, J
¼5.0 Hz, 2H), 7.49 (d, J¼8.1 Hz, 2H), 7.37–7.28 (m, 14H), 7.02
(d, J¼7.0 Hz, 8H), 2.12 (s, 6H);
15
N NMR (500 MHz, CD
3
CN)
d111.9. C ys als sui able o single c ys al X- ay diff ac ion
we e ob ained om a DCM solu ion o 2e apou diffused wi h
E
2
O. C ys al da a o 1a: CCDC-2150096, [C
38
H
34
AgN
2
]BF
4
,M¼
713.35, colou less block, 0.21 0.38 0.50 mm
3
, monoclinic,
space g oup I2/a,a¼18.1676(3) ˚
A, b¼9.4569(2) ˚
A, c¼
37.4652(6) ˚
A, b¼100.690(2),V¼6325.2(2) ˚
A
3
,Z¼8, D
calc
¼
1.498 g cm
3
,F(000) ¼2912, m¼0.69 mm
1
,T¼120.0(1) K,
q
max
¼28.6, 7397 o al eec ions, 6250 wi h I
o
>2s(I
o
), R
in
¼
0.043, 7397 da a, 417 pa ame e s, no es ain s, GooF ¼1.04,
0.38 < dD <0.64 e˚
A
3
,R[F
2
>2s(F
2
)] ¼0.036, wR(F
2
)¼0.079.
Syn hesis o [2–Ag–2]OT (2 ). P epa ed analogously o 1a
using 2(25.9 mg, 0.1 mmol) and AgOT (12.8 mg, 0.05 mmol).
1
H NMR (500 MHz, CD
2
Cl
2
)d7.86 ( d, J¼8.0, 1.7 Hz, 2H), 7.79
(d, J¼4.2 Hz, 2H), 7.42 (d, J¼8.1 Hz, 2H), 7.36–7.26 (m, 14H),
7.04 (d, J¼7.2 Hz, 8H), 2.12 (s, 6H);
15
N NMR (500 MHz, CD
3
CN)
d110.0. C ys als sui able o single c ys al X- ay diff ac ion
we e ob ained om a CHCl
3
solu ion o 2 apou diffused wi h
pen ane. C ys al da a o 1a: CCDC-2150097, [C
39
H
34
AgN
2
]
[CF
3
O
3
S], M¼775.61, colou less pla e, 0.06 0.07 0.32 mm
3
,
monoclinic, space g oup I2/a,a¼19.7243(4) ˚
A, b¼9.1083(2) ˚
A,
c¼37.8599(7) ˚
A, b¼95.788(2),V¼6767.0(2) ˚
A
3
,Z¼8, D
calc
¼
1.523 g cm
3
,F(000) ¼3168, m¼0.72 mm
1
,T¼120.0(1) K,
q
max
¼26.9, 8076 o al eec ions, 6092 wi h I
o
>2s(I
o
), R
in
¼
0.063, 8076 da a, 451 pa ame e s, 101 es ain s, GooF ¼1.07,
0.57 < dD <0.55 e˚
A
3
,R[F
2
>2s(F
2
)] ¼0.046, wR(F
2
)¼0.090.
Theo e ical me hods
Fo he op imisa ions and single poin calcula ions he M06-2X
46
/
de 2-TZVP
47
le el o heo y and he Tu bomole 7.2 p og am
48
was
used. This le el o heo y was p e iously used o s udy simila
complexes.
14–16
The de 2-TZVP implemen a ion used in his wo k
employs o Ag he ECP-28 se and scala ela i is ic effec s.
47
F equency calcula ions we e used o e i y ha he geome ies
co espond o ue minima on he po en ial su ace (no imagi-
na y equencies). No symme y cons ain s we e imposed o he
calcula ions. Sol en calcula ions we e conside ed using he
conduc o -like sc eening model (COSMO).
49
QTAIM and NCIplo
index, ha is adequa e o e eal nonco alen in e ac ions in eal
space,
50
we e compu ed a he same le el o heo y by means o
he MULTIWFN p og am
51
and ep esen ed using he VMD
sowa e.
52
The Wibe g bond index was compu ed using he NBO
7.0 p og am
53
a he same le el o heo y.
Conflic s o in e es
The e a e no conic s o decla e.
Acknowledgemen s
The au ho s g a e ully acknowledge he Magnus Eh n oo h
Founda ion (J. S. W.), he MICIU/AEI o Spain (A. F. p ojec
PID2020-115637GB-I00, FEDER), he Academy o Finland (K. R.
g an no. 317259), and he Uni e si y o Jy askyla, Finland o
nancial suppo .
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