Inducing Single-Handed Helici y in a Twis ed Molecula Nano ibbon
Rajee K. Dubey, Manuel Melle-F anco,*and Au elio Ma eo-Alonso*
Ci e This: J. Am. Chem. Soc. 2022, 144, 2765−2774
Read Online
ACCESS Me ics & Mo e A icle Recommenda ions *
sıSuppo ing In o ma ion
ABSTRACT: Molecula con o ma ion has an impo an ole in chemis y and
ma e ials science. Molecula nano ibbons can adop chi al wis ed helical
con o ma ions. Howe e , he syn hesis o single-handed helically wis ed
molecula nano ibbons s ill ep esen s a conside able challenge. He ein, we
desc ibe an asymme ic app oach o induce single-handed helici y wi h an
excellen deg ee o con o ma ional disc imina ion. The chi al induc ion is he
esul o he chi al s ain gene a ed by using wo o e sized chi al ings and o
he p opaga ion o ha s ain along he nano ibbon’s backbone.
■INTRODUCTION
Con o ma ional isome ism is a undamen al concep in
chemis y ha p o ides an o e all iew o he diffe en spa ial
a angemen s ha he a oms o a molecule can adop . These
a angemen s define he shape(s) o a molecule and de e mine
i s p ope ies. Molecula con o ma ion is pa icula ly ele an
in he biological ac i i y o na u al and syn he ic subs ances,
since bio(mac o)molecules, al hough e y flexible, adop
specific con o ma ions om which unc ion e ol es. Also,
molecula con o ma ion has an impo an ole in chemis y
and ma e ials science, since diffe en con o ma ions may show
diffe en eac i i ies, sel -o ganiza ion beha io , in e ac ion
modes wi h o he molecules, and physical p ope ies.
Nanog aphenes
1−8
polycyclic a oma ic hyd oca bons ha
ex end o e 1 nmcan adop a b oad ange o nonplana
con o ma ions
9−23
ha challenge he pe cep ion o a oma ic
sys ems as igid and fla s uc u es. Among hese, molecula
g aphene nano ibbons (NRs),
2,24−55
monodispe se 1D
nanog aphenescan adop wis ed con o ma-
ions
10,27,31,33,41−43,46−52,56
by in oducing s ain along he
longi udinal edges o he NRs h ough s e ic c owding. In he
case o NRs wi h mo e han wo wis s, helical (Figu e 1a),
al e na ed (Figu e 1b), and mixed helical and al e na ed
con o ma ions can be ob ained. An impo an aspec o helical
con o ma ions is hei inhe en chi ali y, which allows
combining he chi op ical p ope ies ha eme ge om
homochi al molecules wi h he elec onic, op ical, and
elec ical p ope ies ha eme ge om π-ex ended NRs.
Homochi al helical NRs ha e a lo o po en ial in elec onic
and spin onic applica ions ha exploi he abso p ion and
emission o ci cula ly pola ized ligh
57−60
and chi al induced
spin selec i i y.
57,61−63
Despi e he ad ances in he chemis y o molecula
NRs,
2,24−55
he syn hesis o single-handed helically wis ed
molecula NRs s ill ep esen s a conside able challenge. An
impo an aspec is he configu a ional s abili y o he NRs,
which depends on he NR’s edge and on he s e ic hind ance
o he o e c owding g oups. Fo example, he esol ed helical
enan iome s o o e c owded zigzag-edged e abenzopen a-
cenes acemize in solu ion a ambien condi ions (Figu e
1c,d).
47
Ano he example a e co e-edged NRs ha , al hough in
a c ys al s uc u e hey ha e shown o adop an al e na ed
con o ma ion (Figu e 1e, ),
27
in solu ion, as he in e con e -
sion ba ie s a e low, gene ally exis as a op ically inac i e
mix u es o helical, al e na ed, and mixed con o me s in
cons an exchange.
27,48,49,52
Excep ionally, he in e con e sion
ba ie s o NRs wi h jo d edges a e sufficien ly high o yield
configu a ionally s able NRs (Figu e 1g−j),
42,43,51
some o
which ha e been esol ed by chi al high-pe o mance liquid
ch oma og aphy (HPLC).
42
Asymme ic me hods o he
syn hesis o single-handed wis ed NRs, such as chi al
induc ion o enan ioselec i e syn hesis, emain o be
de eloped.
He ein we epo an unp eceden ed app oach o induce he
p e e en ial o ma ion o single-handed helical con o ma ions
in a con o ma ionally flexible molecula NR (Figu e 2). This
ype o NRs a e nonplana because o he s e ic conges ion
Recei ed: No embe 24, 2021
Published: Janua y 31, 2022
A iclepubs.acs.o g/JACS
© 2022 The Au ho s. Published by
Ame ican Chemical Socie y 2765
h ps://doi.o g/10.1021/jacs.1c12385
J. Am. Chem. Soc. 2022, 144, 2765−2774
Downloaded ia UNIV DEL PAIS VASCO on May 12, 2022 a 17:59:18 (UTC).
See h ps://pubs.acs.o g/sha ingguidelines o op ions on how o legi ima ely sha e published a icles.
gene a ed by he inne hyd ogen a oms a he co e egions.
The ou co e egions in he NRs p oduce an insepa able and
op ically inac i e mix u e o helical (Pand M) and al e na ed
con o me s in cons an exchange (Figu e 2a) because o he
low in e con e sion ba ie . Ou app oach o induce single-
handed helici y on such molecula NRs is based on he same
p inciple used o wis a ibbon mac oscopically, namely, he
applica ion o o que o he same sign a he ends o he ibbon
(Figu e 2b). To implemen his p inciple a he molecula
le el, we ha e in oduced wo chi al 8-membe ed diazacy-
clooc a e aene ings by using enan iome ically pu e 1,1′-
binaph hyl-2,2′-diamine (BINAM) p ecu so s a bo h ends o
he a oma ic amewo k. In his p ocess, he axial chi ali y o
BINAM is ans e ed o he newly o med 8-membe ed ings.
The chi al s ain gene a ed by he o e sized chi al 8-membe ed
ings induces he o ma ion o a helical con o me o he same
handedness as he chi al s ain wi h a high deg ee o
con o ma ional disc imina ion. Consequen ly, he chi al NRs
show chi op ical p ope ies ha ex end o e he UV− is up o
600 nm. Theo e ical calcula ions ep oduce he expe imen al
findings and allow confi ming ha he chi al induc ion is a
s ain-induced p ocess.
Figu e 1. Gene al s uc u es o (a) helical and (b) al e na ed con o ma ions o longi udinally wis ed molecula NRs. Examples o wis ed NR
segmen s wi h (c) zigzag,
47
(e) co e,
27
and (g,i) jo d
42,43
edges and hei mos s able (d) helical, ( ) al e na ed, (h) al e na ed, and (j) helical
con o ma ions.
Jou nal o he Ame ican Chemical Socie y pubs.acs.o g/JACS A icle
h ps://doi.o g/10.1021/jacs.1c12385
J. Am. Chem. Soc. 2022, 144, 2765−2774
2766
■RESULTS AND DISCUSSION
Syn hesis and Cha ac e iza ion. The s a ing poin o
he syn hesis o NR-9 is compound NR-7 (Scheme 1) ha was
ob ained by he usion o wo py ene ch omopho es o he bay
egions o a pe ylene bisimide using Suzuki coupling and a
Scholl- ype in amolecula oxida i e cyclodehyd ogena ion
ollowing a epo ed p ocedu e.
46
1-Hexylhep yl and e -
bu yl subs i uen s we e in oduced espec i ely on he pe ylene
and py ene p ecu so s o ensu e he solubili y o he
in e media es and o he final NRs. Then, he K- egions o
bo h py ene esidues o NR-7 we e oxidized o o-dione
unc ionali ies by NaIO4ca alyzed by RuCl3yielding NR-7-
Q.
46
Cyclocondensa ion be ween NR-7-Q wi h ei he (R)-(+)-
o (S)-(−)-BINAM we e ca ied ou in he p esence TiCl4a
. . o yield espec i ely (R,R)-NR-9 and (S,S)-NR-9 as ed
solids in good yields a e pu ifica ion by column ch oma og-
aphy (∼50%).
Despi e hei leng h (3.1 nm) and hei la ge a oma ic co e
cons i u ed by 96 conjuga ed a oms (C92N4), molecula
nano ibbons (R,R)-NR-9 and (S,S)-NR-9 a e highly soluble
Figu e 2. (a) Con o ma ional isome s o NR-7. Pe cen ual con o me popula ions a 25 °C a e indica ed be ween b acke s. (b) Concep ual and
expe imen al app oach o he induc ion o single-handed helici y.
Jou nal o he Ame ican Chemical Socie y pubs.acs.o g/JACS A icle
h ps://doi.o g/10.1021/jacs.1c12385
J. Am. Chem. Soc. 2022, 144, 2765−2774
2767
(∼100 mg/mL) in a a ie y o o ganic sol en s a oom
empe a u e, such as dichlo ome hane, chlo o o m, oluene,
die hyl e he , THF, DMF, and NMP. The s uc u e o (R,R)-
NR-9 and (S,S)-NR-9 was unambiguously es ablished by 1H
and 13C NMR spec oscopy, and high- esolu ion mass
spec ome y. The 1H NMR spec a o (S,S)-NR-9 exhibi ed
well- esol ed p o on signals ha co espond o he binaph hyl,
py ene, and co onene esidues. The signals co esponding o
Scheme 1. Syn hesis o Homochi al Helical Nano ibbons (R,R)-NR-9 and (S,S)-NR-9
Figu e 3. (a) A compa ison o selec ed egions o 1H NMR spec a (CD2Cl2, 500 MHz) o NR-7-Q and (S,S)-NR-9. (b) HR-MS o (S,S)-NR-9.
(c) UV− is abso p ion and fluo escence (colo ed ace) spec a o (S,S)-NR-9 (3.64 μM, λex = 444 nm) in oluene. (d) Cyclic ol ammog am (0.1
MnBu4PF6in CH2Cl2, scan a e = 50 mVs−1)o (S,S)-NR-9.
Jou nal o he Ame ican Chemical Socie y pubs.acs.o g/JACS A icle
h ps://doi.o g/10.1021/jacs.1c12385
J. Am. Chem. Soc. 2022, 144, 2765−2774
2768
enan io opic S2/S2′p o on couple loca ed on he 1-
hexylhep yl spli in o wo indi idual signals ( he le e ing
assignmen s a e shown on Scheme 1), meanwhile in NR-7 and
NR7-Q he same p o on couple esona e oge he (Figu e 3a).
This spli ing indica es he p esence o a chi al en i onmen in
he cen e o he longi udinal edges o a oma ic co e. The
s uc u e o NR-9 was u he confi med by HR MALDI-TOF-
MS spec a ha showed he molecula ion peak (M+) and
iso opic dis ibu ions consis en wi h he molecula weigh
(Figu e 3b).
Op oelec onic and Redox P ope ies. Solu ions o NR-
9show an in ense ed colo (see le inse o Figu e 3c) simila
o he solid powde s. Exposu e o he solu ions o UV ligh
e idence an o ange emission (see igh inse o Figu e 3c). The
UV− is elec onic abso p ion spec a o (S,S)-NR-9 exhibi ed
an in ense abso p ion wi h h ee majo bands a 396, 476, and
576 nm (Figu e 3c). These bands can be a ibu ed o he
cen al py ene-co onene-py ene co e in ag eemen wi h he
spec a o NR-7 (Figu e S1) and co onene bisimides.
64
Meanwhile he bands co esponding o he BINAM esidues
o e lap wi h hose o he cen al co e in he egion be ween
300 and 380 nm (Figu e S1). An op ical HOMO−LUMO gap
(Egap) o 2.1 eV was es ima ed om he onse o he lowes
ene gy abso p ion band (Table S1). The emission spec um o
(S,S)-NR-9 show a fluo escence band wi h maxima a 585 nm
and wi h clea ib onic ea u es ha mi o he lowes ene gy
band wi h a quan um yield o 27%, and a S okes shi o 267
cm−1(Figu e 3c). The fluo escence ene gy is consis en wi h
he o ange emission obse ed. The edox p ope ies o NR-9
we e in es iga ed by cyclic ol amme y in CH2Cl2wi h
nBu4PF6as he suppo ing elec oly e (Figu e 3d). (S,S)-NR-9
exhibi ed h ee educ ion wa es wi h hal -wa e po en ials
(E1/2)a −1.31, −1.59, and a peak po en ial (Ep)a −1.99 V
e sus Fc/Fc+, espec i ely. An elec ochemical LUMO o
elec on affini y o (S,S)-NR-9 (ELUMO)o −3.6 eV was
es ima ed om he onse o he fi s educ ion po en ial.
Con o ma ional Analysis. Calcula ions (B3LYP-6-31G-
(d,p)) we e ca ied ou o shine ligh on he con o ma ional
landscape o NR-9. Fi s , we ocused on a model compound o
NR-7, namely NR-7-H, in which he e -bu yl and 1-
hexylhep yl g oups ha e been eplaced espec i ely by
hyd ogen a oms and me hyl g oups o simplici y and
compu a ional efficiency. The calcula ions e idence wo
con o ma ions accessible a 25 °C in cons an exchange,
namely one al e na ed (meso) and one helical wi h wo
enan iome s (Pand M) wi h e y simila ene gies (Figu e 2a).
The al e na ed con o me is he mos s able and he mos
popula ed (64%), while he helical con o me is sligh ly less
s able (+0.34 kcal/mol) wi h a popula ion (36%) ha is
equally dis ibu ed be ween he wo helical enan iome s.
A comple ely diffe en end was obse ed on he model
NR-9-H, in which he e -bu yl and 1-hexylhep yl g oups o
NR-9 ha e also been eplaced espec i ely by hyd ogen a oms
and me hyl g oups. Th ee con o ma ions we e ound o be
accessible a 25 °C(Figu e 4), a helical con o ma ion wi h he
same handedness as he chi al s ain (P-(R,R)-NR-9-H), an
al e na ed con o ma ion (P,M-(R,R)-NR-9-H), and a helical
con o ma ion wi h he opposi e handedness o ha o he
chi al s ain (M-(R,R)-NR-9-H). The helical P-(R,R)-NR-9-H
con o ma ion is he mos s able, ollowed by he al e na ed
P,M-(R,R)-NR-9-H (+1.63 kcal/mol) and he helical M-(R,R)-
NR-9-H (+3.70 kcal/mol). The ela i e popula ions e idence
how he chi al ing s ain gene a ed by he diazacyclooc a e-
aene ings induces almos exclusi ely he o ma ion o he P-
(R,R)-NR-9-H con o ma ion (93.8%), whe eas he con ibu-
ions o he al e na ed P,M-(R,R)-NR-9-H (6.0%) and o he
M-(R,R)-NR-9-H (0.2%) con o ma ions a e almos esidual.
The usion o he (S)-(−)-BINAM enan iome induces helici y
in he opposi e di ec ion gene a ing again almos exclusi ely
he M-(S,S)-NR-9-H con o me wi h he same deg ee o
con o ma ional disc imina ion.
Chi op ical P ope ies and Absolu e Configu a ion.
To confi m expe imen ally he heo e ical con o ma ional
analysis, he chi op ical p ope ies o he NRs we e measu ed
by ci cula dich oism (CD) measu emen s and he CD spec a
we e compa ed wi h he calcula ed CD spec a om he
simula ed con o ma ions.
The CD spec um o NR-7 exhibi ed no Co on effec
(Figu e S2),whichisconsis en wi h hecons an
in e con e sion be ween he helical and al e na ed con o ma-
ions obse ed in he calcula ions (Figu e 2a).
Con e sely, bo h (R,R)-NR-9 and (S,S)-NR-9 enan iome s
exhibi ed mi o -image CD spec al pa e ns in a wa eleng h
ange be ween 300 and 600 nm (Figu e 5a), in ag eemen wi h
Figu e 4. Calcula ed con o ma ions, ee ene gies, and pe cen ual ela i e popula ions o (R,R)-NR-9-H a 25 °C (B3LYP-6-31G(d,p)).
Jou nal o he Ame ican Chemical Socie y pubs.acs.o g/JACS A icle
h ps://doi.o g/10.1021/jacs.1c12385
J. Am. Chem. Soc. 2022, 144, 2765−2774
2769
he abso p ion spec a, and Δε alues ha each ±100 M−1
cm−1. The heo e ical spec a o he homochi al helical
con o me s o P-(R,R)-NR-9-H and M-(S,S)-NR-9-H (Figu e
5b) a e in excellen ag eemen wi h he expe imen al ones
(Figu e 5a), whe eas a comple ely diffe en CD pa e n has
been ob ained o he al e na ed con o me s P,M-(R,R)-NR-9-
Hand M,P-(S,S)-NR-9-H (Figu e 5c). Also, he simula ed CD
spec um o he 94:6 P-(R,R)-NR-9-H/P,M-(R,R)-NR-9-H
mix u e p edic ed by he calcula ions a 25 °C shows a CD
spec um (Figu e S3) wi h nea ly no diffe ences o ha o he
homochi al P-(R,R)-NR-9-H. This unambiguously confi ms
ha he chi al 8-membe ed ing induces almos exclusi ely he
o ma ion o he helical con o me o he same handedness as
he chi al s ain.
To u he e i y hese assignmen s, we syn hesized and
s udied (R,S)-NR-9 (Scheme S1) wi h wo BINAM esidues o
opposi e chi ali y as a e e ence compound. Theo e ical
calcula ions (Figu e S4) e idence a majo al e na ed meso
con o me (meso-P,M-(R,S)-NR-9-H, 96.3%) wo esidual
con o me s, namely an asymme ic (P-(R,S)-NR-9-H, 3.4%)
and a meso al e na ed (meso-M,P-(R,S)-NR-9-H,0.2%)
con o me . The CD expe imen al spec um o he (R,S)-NR-
9exhibi s no Co on effec (Figu e S5), which is again in
ag eemen wi h he simula ed CD spec um o he majo meso-
P,M-(R,S)-NR-9-H con o me ha also shows no dich oic
signals (Figu e S5).
To s udy he effec s o he empe a u e on he popula ions
o he diffe en con o ma ional isome s, a iable empe a u e
CD measu emen s we e ca ied ou on (S,S)-NR-9 be ween 0
and 100 °C(Figu e 5d). This empe a u e window alls wi hin
he configu a ional s abili y empe a u e o BINAM (up o 170
°C
65
). Upon cooling, he CD spec a show he g adual inc ease
o he in ensi y o he bands a 348, 480, and 579 nm, and he
a enua ion o he band a 398 nm, whe eas upon hea ing,
spec al changes in he opposi e di ec ion a e obse ed. Mos
impo an ly, he in ensi y o he o iginal dich oic signals is
es o ed a e b inging he sample back o 25 °C. This
e e sibili y confi ms ha no acemiza ion has aken place a
he BINAM esidues, and he e o e, ha all he CD spec al
changes wi h espec o he empe a u e a e he esul o he
dynamic na u e o he molecula NRs. In addi ion, UV− is
elec onic abso p ion spec a o (S,S)-NR-9 a diffe en
empe a u es (Figu e S6) show i ually no diffe ences. This
confi ms ha he obse ed changes on he CD spec a a
diffe en empe a u es a e no ela ed o elec onic effec s bu
o changes on he ela i e popula ions o he con o me s.
Theo e ical calcula ions show ha he obse ed changes o he
CD spec a wi h espec o he empe a u e a e consis en wi h
he posi i e con o ma ional disc imina ion in a o o he
helical M-(S,S)-NR-9-H con o me a empe a u es below
oom empe a u e (95.1% a 0 °C) (Table S2). Meanwhile, he
disc imina ion owa d he helical M-(S,S)-NR-9-H con o me
dec eases a inc easing empe a u es abo e oom empe a u e
(89.4% a 100 °C) in a o o he M,P-(S,S)-NR-9-H and he
P-(S,S)-NR-9-H con o me s (Table S2). The simula ed CD
spec a calcula ed wi h inc easing popula ion a ios o M-(S,S)-
NR-9-H show he same end as ha obse ed expe imen ally
(Figu e S7). Ye , he sub le compu ed ee ene gy diffe ence, 2
kcal/mol, appea s o be o e es ima ed, which may be
connec ed o he lack o anha monic effec s o o he dynamic
o sol en ela ed effec s in ou model (Table S3).
S uc u al Analysis and Elec onic S uc u e. The
excellen co ela ion be ween expe imen al and calcula ed
CD spec a allows us o ge a di ec insigh in o he s uc u e o
he mos s able homochi al helical con o ma ion o NR-9. The
model o M-(S,S)-NR-9-H (Figu e 6a,b) shows a highly
wis ed helical con o ma ion wi h an end- o-end wis angle o
281° om he diazacyclooc a e aene ends (ØABCD, le e ing
shown in Figu e 6a). The py ene- o-py ene end- o-end wis
angle (ØEFGH = 126°) and he py ene end- o-end wis angle
(ØGHIJ =45°) a e highe by app oxima ely a ac o o 2 han
hose obse ed on he less-s able helical con o me o NR-7-H
(ØEFGH =68°and ØGHIJ =17°). The highe wis angle alues
o M-(S,S)-NR-9-H a e he esul o he chi al s ain
Figu e 5. (a) CD spec a o (R,R)-NR-9 and (S,S)-NR-9 (10 μM, 1 cm pa h leng h) in oluene. (b) Simula ed CD spec a o P-(R,R)-NR-9-H and
M-(S,S)-NR-9-H. (c) Simula ed CD o P,M-(R,R)-NR-9-H and M,P-(S,S)-NR-9-H. (d) VT CD spec a o (S,S)-NR-9 in oluene.
Jou nal o he Ame ican Chemical Socie y pubs.acs.o g/JACS A icle
h ps://doi.o g/10.1021/jacs.1c12385
J. Am. Chem. Soc. 2022, 144, 2765−2774
2770
gene a ed by he usion o he o e sized 8-membe ed
diazacyclooc a e aene ings and o he addi ional o sion
gene a ed by he homochi al BINAM esidues. Fo ins ance,
he bond-leng h plo s show la ge bond dis ances (shown in
blue in Figu e 6a) a he diazacyclooc a e aene-py ene and
py ene-co onene junc ions. Also, he s ain plo s (S ainViz
66
)
show a high s ain (shown in o ange and ed in Figu e 6b) a
he diazacyclooc a e aene-py ene junc ions. The p opaga ion
o such chi al s ain along he NR’s backbone s abilizes he
helical con o ma ion o he same handedness as he chi al
s ain.
On he basis o he bond leng h al e na ion (Figu e 6a) and
he nucleus-independen chemical shi (NICS(0)) alues
(Figu e 6c), he dominan esonance s uc u e in M-(S,S)-NR-
9-H is bes ep esen ed by a co onene g oup (3 sex e s) in he
co onene esidues, wo biphenyl g oups (2 sex e s) in he
py ene esidues, a cyclooc a e aene g oup (an ia oma ic) in
he diazacyclooc a e aene esidue, and wo naph halene
g oups (1 sex e ) in he BINAM esidues. Fo ins ance,
nega i e NICS(0) alues (Figu e 6c) we e ound on almos all
he ings o he co onene py ene and naph halene esidues
(shown in ed). Also, he diazacyclooc a e aene ings, linea ly
annula ed py ene ings, and he cen al co onene ings show
posi i e and nea ly posi i e alues (shown in blue). The
aniso opy o he induced cu en densi y (ACID) plo s o M-
(S,S)-NR-9-H (Figu e 6d) a e also consis en wi h his
assignmen and show a diamagne ic cu en ha goes a ound
he NR edges.
To shine addi ional ligh on he op oelec onic p ope ies,
DFT calcula ions (B3LYP-6-31G(d,p)) we e ca ied ou on M-
(S,S)-NR-9-H. The compu ed Egap (2.38 eV) and ELUMO
(−3.17 eV) o M-(S,S)-NR-9-H a e simila o he
Figu e 6. (a) Bond leng h plo s, (b) s ain plo s, (c) NICS(0) alues, (d) ACID plo , and (e) o bi als o M-(S,S)-NR-9-H. The o bi als highligh ed
wi h s a s in (a) indica e hose in ol ed in he lowes ene gy ansi ion.
Jou nal o he Ame ican Chemical Socie y pubs.acs.o g/JACS A icle
h ps://doi.o g/10.1021/jacs.1c12385
J. Am. Chem. Soc. 2022, 144, 2765−2774
2771
expe imen al ones (Table S4). TD-DFT (Table S5) e eal ha
he lowes ene gy exci a ion o igina es om a HOMO−2→
LUMO ansi ion, as bo h HOMO →LUMO and HOMO−1
→LUMO exci a ions a e da k. The HOMO−2 is delocalized
ac oss he whole a oma ic co e wi h mos o he elec on
densi y loca ed o e he py ene-co onene-py ene esidues, and
despi e he highly wis ed s uc u e i shows some elec on
densi y o e he diazacyclooc a e aene and binaph hyl
esidues (Figu e 6e), whe eas he LUMO is mos ly localized
o e he co onene bisimide esidue.
The simila bond leng hs (Figu e S8), s ain plo (Figu e
S9), NICS(0) alues (Figu e S10), ACID plo (Figu e S11),
and o bi al shapes and ene gies (Figu e S12 and Tables S4−
S5) obse ed in he al e na ed M,P-(S,S)-NR-9-H con o me
indica e ha he e is no any elec onic con ibu ion o he
ela i e con o me popula ions, and he e o e, ha chi al
induc ion is only a s ain-induced p ocess.
■CONCLUSIONS
We ha e epo ed an unp eceden ed app oach o induce
single-handed helici y in con o ma ionally flexible NRs wi h an
excellen deg ee o con o ma ional disc imina ion. Such chi al
induc ion is he esul o he chi al s ain gene a ed by using
wo o e sized chi al ings and o he p opaga ion o ha chi al
s ain along he NR’s backbone. The chi al NRs p oduce
dich oic signals in a b oad spec al ange up o 600 nm. The
simula ion o he expe imen al dich oic spec al pa e ns o he
chi al NRs allow confi ma ion ha he chi al 8-membe ed
ings s abilize he helical con o ma ion o he same handedness
as he chi al s ain. O e all, his asymme ic app oach pa es he
way o he syn hesis o mo e complex homochi al nano-
g aphenes, which in u n will enable u he de elopmen s in
elec onic and spin onic applica ions ha exploi he
abso p ion and emission o ci cula ly pola ized ligh and chi al
induced spin selec i i y.
■ASSOCIATED CONTENT
*
sıSuppo ing In o ma ion
The Suppo ing In o ma ion is a ailable ee o cha ge a
h ps://pubs.acs.o g/doi/10.1021/jacs.1c12385.
Expe imen al de ails o he syn hesis, cha ac e iza ion,
and calcula ions (PDF)
■AUTHOR INFORMATION
Co esponding Au ho s
Manuel Melle-F anco −CICECO, A ei o Ins i u e o
Ma e ials, Depa men o Chemis y, Uni e si y o A ei o,
3810-193 A ei o, Po ugal; o cid.o g/0000-0003-1929-
0477; Email: [email p o ec ed]
Au elio Ma eo-Alonso −POLYMAT, Uni e si y o he
Basque Coun y UPV/EHU, 20018 Donos ia-San Sebas ian,
Spain; Ike basque, Basque Founda ion o Science, 48009
Bilbao, Spain; Email: [email p o ec ed]
Au ho
Rajee K. Dubey −POLYMAT, Uni e si y o he Basque
Coun y UPV/EHU, 20018 Donos ia-San Sebas ian, Spain
Comple e con ac in o ma ion is a ailable a :
h ps://pubs.acs.o g/10.1021/jacs.1c12385
No es
The au ho s decla e no compe ing financial in e es .
■ACKNOWLEDGMENTS
This wo k was ca ied ou wi h suppo om he Basque
Science Founda ion o Science (Ike basque), POLYMAT, he
Uni e si y o he Basque Coun y, Gobie no Vasco (BERC
P og amme) and Gobie no de Espana (Minis e io de Ciencia e
Inno ación, Plan Es a al de In es igación Cien ífica y Técnica
y de Inno ación). Technical and human suppo p o ided by
SGIke o UPV/EHU and Eu opean unding (ERDF and ESF)
is acknowledged. This p ojec has ecei ed unding om he
Eu opean Resea ch Council (ERC) unde he Eu opean
Union’s Ho izon 2020 esea ch and inno a ion p og amme
(G an Ag eemen No. 722951). This p ojec has ecei ed
unding om he Eu opean Union’s Ho izon 2020 esea ch
and inno a ion p og amme unde G an Ag eemen No.
899895. In addi ion, suppo h ough he p ojec IF/00894/
2015, he ad anced compu ing p ojec CPCA/A2/2524/2020
g an ing access o he Na iga o clus e a LCA-UC and wi hin
he scope o he p ojec CICECO-A ei o Ins i u e o Ma e ials,
UIDB/50011/2020 and UIDP/50011/2020 unded by na-
ional unds h ough he Po uguese Founda ion o Science
and Technology I.P./MCTES is g a e ully acknowledged.
■ABBREVIATIONS
NR, g aphene nano ibbon; HPLC, high-pe o mance liquid
ch oma og aphy; BINAM, 1,1′-binaph hyl-2,2′-diamine; THF,
e ahyd o u an; DMF, N,N-dime hyl o mamide; NMP, N-
me hyl py olidone; NMR, nuclea magne ic esonance; HR
MALDI-TOF-MS, high- esolu ion ma ix-assis ed lase deso p-
ion/ioniza ion ime-o -fligh mass spec ome y; CD, ci cula
dich oism; VT-CD, a iable empe a u e ci cula dich oism;
NICS, nuclea independen chemical shi s; ACID, aniso opy
o he induced cu en densi y; DFT, densi y unc ional heo y;
HOMO, highes occupied molecula o bi al; LUMO, lowes
unoccupied molecula o bi al.
■REFERENCES
(1) Na i a, A. Syn hesis o S uc u ally Defined Nanog aphene
Ma e ials h ough Oxida i e Cyclodehyd ogena ion. In Syn he ic
Me hods o Conjuga ed Polyme s and Ca bon Ma e ials; Wiley-VCH
Ve lag GmbH & Co. KGaA: Weinheim, 2017; pp 183−228.
(2) Ma eo-Alonso, A. Py ene- used py azaacenes: om small
molecules o nano ibbons. Chem. Soc. Re . 2014,43 (17), 6311−
6324.
(3) Na i a, A.; Wang, X.-Y.; Feng, X.; Mullen, K. New ad ances in
nanog aphene chemis y. Chem. Soc. Re . 2015,44 (18), 6616−6643.
(4) S ępien, M.; Gonka, E.; Zyła, M.; Sp u a, N. He e ocyclic
Nanog aphenes and O he Polycyclic He e oa oma ic Compounds:
Syn he ic Rou es, P ope ies, and Applica ions. Chem. Re . 2017,117
(4), 3479−3716.
(5) Wang, X. Y.; Yao, X.; Na i a, A.; Mullen, K. He e oa om-Doped
Nanog aphenes wi h S uc u al P ecision. Acc. Chem. Res. 2019,52
(9), 2491−2505.
(6) G zybowski, M.; Sadowski, B.; Bu enschon, H.; G yko, D. T.
Syn he ic Applica ions o Oxida i e A oma ic Coupling-F om
Biphenols o Nanog aphenes. Angew. Chem., In . Ed. 2020,59 (8),
2998−3027.
(7) Liu, J.; Feng, X. Syn he ic Tailo ing o G aphene Nanos uc u es
wi h Zigzag-Edged Topologies: P og ess and Pe spec i es. Angew.
Chem., In . Ed. 2020,59 (52), 23386−23401.
(8) Zeng, W.; Wu, J. Open-Shell G aphene F agmen s. Chem. 2021,
7(2), 358−386.
(9) Pascal, R. A., J . Twis ed acenes. Chem. Re . 2006,106 (12),
4809−19.
Jou nal o he Ame ican Chemical Socie y pubs.acs.o g/JACS A icle
h ps://doi.o g/10.1021/jacs.1c12385
J. Am. Chem. Soc. 2022, 144, 2765−2774
2772
(10) Rickhaus, M.; Mayo , M.; Ju ícek, M. S ain-induced helical
chi ali y in polya oma ic sys ems. Chem. Soc. Re . 2016,45 (6),
1542−56.
(11) Rickhaus, M.; Mayo , M.; Ju ícek, M. Chi ali y in cu ed
polya oma ic sys ems. Chem. Soc. Re . 2017,46 (6), 1643−1660.
(12) Pun, S. H.; Miao, Q. Towa d Nega i ely Cu ed Ca bons. Acc.
Chem. Res. 2018,51 (7), 1630−1642.
(13) Ball, M.; Zhong, Y.; Wu, Y.; Schenck, C.; Ng, F.; S eige wald,
M.; Xiao, S.; Nuckolls, C. Con o ed polycyclic a oma ics. Acc. Chem.
Res. 2015,48 (2), 267−76.
(14) Fe nandez-Ga cia, J. M.; E ans, P. J.; Filippone, S.; He anz, M.
A.; Ma in, N. Chi al Molecula Ca bon Nanos uc u es. Acc. Chem.
Res. 2019,52 (6), 1565−1574.
(15) S a a, I. G.; S a y, I. Helically Chi al A oma ics: The Syn hesis
o Helicenes by [2 + 2 + 2] Cycloisome iza ion o pi-Elec on
Sys ems. Acc. Chem. Res. 2020,53 (1), 144−158.
(16) Zhu, Y.; Xia, Z.; Cai, Z.; Yuan, Z.; Jiang, N.; Li, T.; Wang, Y.;
Guo, X.; Li, Z.; Ma, S.; Zhong, D.; Li, Y.; Wang, J. Syn hesis and
Cha ac e iza ion o Hexapole [7]Helicene, A Ci cula ly Twis ed
Chi al Nanog aphene. J. Am. Chem. Soc. 2018,140 (12), 4222−4226.
(17) Guo, X.; Yuan, Z.; Zhu, Y.; Li, Z.; Huang, R.; Xia, Z.; Zhang,
W.; Li, Y.; Wang, J. A Ni ogen-Doped Hexapole [7]Helicene e sus
I s All-Ca bon Analogue. Angew. Chem., In . Ed. 2019,58 (47),
16966−16972.
(18) Wang, Y.; Yin, Z.; Zhu, Y.; Gu, J.; Li, Y.; Wang, J. Hexapole
[9]Helicene. Angew. Chem., In . Ed. 2019,58 (2), 587−591.
(19) Zhu, Y.; Guo, X.; Li, Y.; Wang, J. Fusing o Se en HBCs owa d
a G een Nanog aphene P opelle . J. Am. Chem. Soc. 2019,141 (13),
5511−5517.
(20) Mo a-Fuen es, J. P.; Riano, A.; Co izo-Lacalle, D.; Saeki, A.;
Melle-F anco, M.; Ma eo-Alonso, A. Gian S a -Shaped Ni ogen-
Doped Nanog aphenes. Angew. Chem., In . Ed. 2019,58 (2), 552−
556.
(21) Chen, Y.; Lin, C.; Luo, Z.; Yin, Z.; Shi, H.; Zhu, Y.; Wang, J.
Double Pi-Ex ended Undecabenzo[7]helicene. Angew. Chem., In . Ed.
2021,60, 7796−7801.
(22) Tan, Y.-Z.; Yang, B.; Pa ez, K.; Na i a, A.; Osella, S.; Beljonne,
D.; Feng, X.; Mullen, K. A omically p ecise edge chlo ina ion o
nanog aphenes and i s applica ion in g aphene nano ibbons. Na .
Commun. 2013,4(1), 2646.
(23) Chaolumen; S epek, I. A.; Yamada, K. E.; I o, H.; I ami, K.
Cons uc ion o Hep agon-Con aining Molecula Nanoca bons.
Angew. Chem., In . Ed. 2021,60, 23508−23532.
(24) Schlicke, B.; Schlu e , A. D.; Hause , P.; Heinze, J. Polycyclic
A oma ic Hyd oca bons in he Nanome e Range. Angew. Chem., In .
Ed. 1997,36 (18), 1996−1998.
(25) Pu usho haman, B.; B uzek, M.; Pa kin, S. R.; Mille , A.-F.;
An hony, J. E. Syn hesis and S uc u al Cha ac e iza ion o C ys alline
Nonacenes. Angew. Chem., In . Ed. 2011,50 (31), 7013−7017.
(26) Chen, L.; Li, C.; Mullen, K. Beyond pe ylene diimides:
syn hesis, assembly and unc ion o highe ylene ch omopho es. J.
Ma e . Chem. C 2014,2(11), 1938−1956.
(27) Liu, J.; Li, B.-W.; Tan, Y.-Z.; Giannakopoulos, A.; Sanchez-
Sanchez, C.; Beljonne, D.; Ru ieux, P.; Fasel, R.; Feng, X.; Mullen, K.
Towa d Co e-Edged Low Band Gap G aphene Nano ibbons. J. Am.
Chem. Soc. 2015,137 (18), 6097−6103.
(28) Ozaki, K.; Kawasumi, K.; Shiba a, M.; I o, H.; I ami, K. One-
sho K- egion-selec i e annula i e π-ex ension o nanog aphene
syn hesis and unc ionaliza ion. Na . Commun. 2015,6, 6251.
(29) Huang, R.; Phan, H.; He ng, T. S.; Hu, P.; Zeng, W.; Dong, S.-
q.; Das, S.; Shen, Y.; Ding, J.; Casano a, D.; Wu, J. Highe O de π-
Conjuga ed Polycyclic Hyd oca bons wi h Open-Shell Single
G ound S a e: Nonaze h ene e sus Nonacene. J. Am. Chem. Soc.
2016,138 (32), 10323−10330.
(30) Zeng, W.; Phan, H.; He ng, T. S.; Gopalak ishna, T. Y.; A a ani,
N.; Zeng, Z.; Yamada, H.; Ding, J.; Wu, J. Rylene Ribbons wi h
Unusual Di adical Cha ac e . Chem. 2017,2(1), 81−92.
(31) Fan, W.; Winands, T.; Dol sinis, N. L.; Li, Y.; Wang, Z. A
Deca wis acene wi h an O e all 170 deg ees To sion. Angew. Chem.,
In . Ed. 2017,56 (48), 15373−15377.
(32) Lee, J.; Li, H.; Kalin, A. J.; Yuan, T.; Wang, C.; Olson, T.; Li,
H.; Fang, L. Ex ended Ladde -Type Benzo[k] e aphene-De i ed
Oligome s. Angew. Chem., In . Ed. 2017,56 (44), 13727−13731.
(33) Chen, W.; Li, X.; Long, G.; Li, Y.; Ganguly, R.; Zhang, M.;
A a ani, N.; Yamada, H.; Liu, M.; Zhang, Q. Py ene-Con aining
Twis a ene: Twel e Benzene Rings Fused in a Row. Angew. Chem.,
In . Ed. 2018,57 (41), 13555−13559.
(34) Cai, Z.; Awais, M. A.; Zhang, N.; Yu, L. Explo a ion o
Syn heses and Func ions o Highe Ladde - ype π-Conjuga ed
He e oacenes. Chem. 2018,4(11), 2538−2570.
(35) Co izo-Lacalle, D.; Mo a-Fuen es, J. P.; S u ynski, K.; Saeki,
A.; Melle-F anco, M.; Ma eo-Alonso, A. Monodispe se N-Doped
G aphene Nano ibbons Reaching 7.7 Nanome e s in Leng h. Angew.
Chem., In . Ed. 2018,57 (3), 703−708.
(36) Co izo-Lacalle, D.; Gozal ez, C.; Melle-F anco, M.; Ma eo-
Alonso, A. A hiadiazole-capped nano ibbon wi h 18 linea ly used
ings. Nanoscale 2018,10 (24), 11297−11301.
(37) Jin, P.; Song, T.; Xiao, J.; Zhang, Q. Recen P og ess in Using
Py ene-4,5-dike ones and Py ene-4,5,9,10- e ake ones as Building
Blocks o Cons uc La ge Acenes and He e oacenes. Asian J. O g.
Chem. 2018,7(11), 2130−2146.
(38) Bunz, U. H. F.; F eudenbe g, J. N-He e oacenes and N-
He e oa enes as N-Nanoca bon Segmen s. Acc. Chem. Res. 2019,52
(6), 1575−1587.
(39) Chen, W.; Yu, F.; Xu, Q.; Zhou, G.; Zhang, Q. Recen P og ess
in High Linea ly Fused Polycyclic Conjuga ed Hyd oca bons (PCHs,
n> 6) wi h Well-De ined S uc u es. Ad . Sci. 2020,7(12), 1903766.
(40) Peu i oy, S. R.; Sis o, T. J.; Ng, F.; S eige wald, M. L.; Chen, R.;
Nuckolls, C. Dimensional Con ol in Con o ed A oma ic Ma e ials.
Chem. Rec. 2019,19 (6), 1050−1061.
(41) Liu, G.; Xiao, C.; Neg i, F.; Li, Y.; Wang, Z. Dodeca wis a ene
Imides wi h Zigzag-Twis ed Con o ma ion o O ganic Elec onics.
Angew. Chem., In . Ed. 2020,59 (5), 2008−2012.
(42) Ma, S.; Gu, J.; Lin, C.; Luo, Z.; Zhu, Y.; Wang, J.
Supe wis acene: A Helical G aphene Nano ibbon. J. Am. Chem.
Soc. 2020,142 (39), 16887−16893.
(43) Cas o-Fe nández, S.; C uz, C. M.; Ma iz, I. F. A.; Má quez, I.
R.; Jiménez, V. G.; Palomino-Ruiz, L.; Cue a, J. M.; Macoas, E.;
Campana, A. G. Two-Pho on Abso p ion Enhancemen by he
Inclusion o a T opone Ring in Dis o ed Nanog aphene Ribbons.
Angew. Chem., In . Ed. 2020,59 (18), 7139−7145.
(44) Yang, X.; Rominge , F.; Mas ale z, M. Benzo- used Pe ylene
Oligome s wi h up o 13 Linea ly Annula ed Rings. Angew. Chem., In .
Ed. 2021,60, 7941−7946.
(45) Chen, F.; Gu, W.; Saeki, A.; Melle-F anco, M.; Ma eo-Alonso,
A. A S e ically Conges ed Ni ogena ed Benzodipen aphene wi h a
Double π-Expanded Helicene S uc u e. O g. Le . 2020,22 (9),
3706−3711.
(46) Dubey, R. K.; Melle-F anco, M.; Ma eo-Alonso, A. Twis ed
Molecula Nano ibbons wi h up o 53 Linea ly-Fused Rings. J. Am.
Chem. Soc. 2021,143 (17), 6593−6600.
(47) Lu, J.; Ho, D. M.; Vogelaa , N. J.; K aml, C. M.; Pascal, R. A. A
Pen acene wi h a 144°Twis . J. Am. Chem. Soc. 2004,126 (36),
11168−11169.
(48) Zhong, Y.; Kuma , B.; Oh, S.; T inh, M. T.; Wu, Y.; Elbe , K.;
Li, P.; Zhu, X.; Xiao, S.; Ng, F.; S eige wald, M. L.; Nuckolls, C.
Helical Ribbons o Molecula Elec onics. J. Am. Chem. Soc. 2014,
136 (22), 8122−8130.
(49) Sis o, T. J.; Zhong, Y.; Zhang, B.; T inh, M. T.; Miya a, K.;
Zhong, X.; Zhu, X. Y.; S eige wald, M. L.; Ng, F.; Nuckolls, C. Long,
A omically P ecise Dono −Accep o Co e-Edge Nano ibbons as
Elec on Accep o s. J. Am. Chem. Soc. 2017,139 (16), 5648−5651.
(50) C uz, C. M.; Má quez, I. R.; Ma iz, I. F. A.; Blanco, V.;
Sánchez-Sánchez, C.; Sob ado, J. M.; Ma ín-Gago, J. A.; Cue a, J.
M.; Macoas, E.; Campana, A. G. Enan iopu e dis o ed ibbon-shaped
nanog aphene combining wo-pho on abso p ion-based upcon e sion
Jou nal o he Ame ican Chemical Socie y pubs.acs.o g/JACS A icle
h ps://doi.o g/10.1021/jacs.1c12385
J. Am. Chem. Soc. 2022, 144, 2765−2774
2773
