Tris(tetraceno)triquinacenes: Synthesis and photophysical properties of threefold linearly extended tribenzotriquinacenes

Article abstract of DOI:10.1002/chem.201303031

The linear extension of the rigid, C_3v-symmetrical carbon framework of tribenzotriquinacene (TBTQ) along its three wings is reported. The key step of the extension procedure consists of a Diels-Alder reaction of three ortho-quinodimethane units generated in situ at the triquinacene core. The use of 1,4-naphthoquinone provides a facile and particularly efficient access to tris(tetraceno)-annellated triquinacenes. The steady-state photophysical properties of these new oligotetracenes bearing three mutually orthogonal chomophores are determined and analyzed by DFT calculations. Copyright

Full text of DOI:10.1002/chem.201303031

FULL PAPER
DOI: 10.1002/chem.201303031
Tris(tetraceno)triquinacenes: Synthesis and Photophysical Properties of
Threefold Linearly Extended Tribenzotriquinacenes
Ehsan Ullah Mughal, Jens Eberhard, and Dietmar Kuck*[a]
Dedicated to Professor Dr. Eckehard V. Dehmlow on the occasion of his 80th birthday
Abstract: The linear extension of the rigid, C3v-symmetrical carbon framework of
tribenzotriquinacene (TBTQ) along its three wings is reported. The key step of
the extension procedure consists of a Diels–Alder reaction of three ortho-quinodi-
Keywords: acenes · photophysics ·
methane units generated in situ at the triquinacene core. The use of 1,4-naphtho-
polycyclic compounds · quinones ·
quinone provides a facile and particularly efficient access to tris(tetraceno)-annel-
UV/Vis spectroscopy
lated triquinacenes. The steady-state photophysical properties of these new oligo-
tetracenes bearing three mutually orthogonal chomophores are determined and
analyzed by DFT calculations.
Introduction
Acenes represent one of the most important structural
motifs for polycyclic aromatic hydrocarbons,[1] graphene,[2]
and carbon nanotubes.[3] Among them, tetracenes and pent-
ACHTUNGTRENNUNGacenes have experienced considerable attention because of
their excellent performance in the field of organic electron-
ics.[4–10] In particular, charge carrier mobility was found to
depend on the ability of acenes to aggregate into highly or-
ganized molecular stacks to enable maximum p-orbital over-
lap within the crystal lattice.[4a,11] However, the poor solubili-
ty and low chemical stability of the higher parent acenes
have limited their detailed exploration,[1a,12] and methods to
circumvent this problem by bending the acene plane have
been developed.[13]
In the present work, three acene units have been incorpo-
rated into the three-dimensional framework of tribenzotri-
quinacene (TBTQ, 1).[14–16] This polycyclic hydrocarbon be-
longing to the centropolyindane family[17] has a conforma-
tionally rigid and highly symmetrical (C3v) carbon frame-
work consisting of three indane wings oriented orthogonally
to each other (A, Figure 1).[17–19] Owing to this unique spa-
tial arrangement and the bowl-shaped architecture of 1, we
expected increased solubility of threefold aceno-annellated
triquinacenes, such as B, which would contribute a new facet
to the field.[20,21] Different from triptycenes bearing three
acene wings oriented perpendicular to a common plane and
Figure 1. Parent tribenzotriquinacene (TBTQ, 1), the single-wing-extend-
ed TBTQ derivative 2[28] and the (yet unknown) parent tris(2,3-tetrace-
no)triquinacene B. The insert A provides a view along the axis of one
indane wing of 1, illustrating the almost perfect orthogonal orientation of
the other two (a=888).[18,19]
mutually at 1208,[22] TBTQ-based acenes would stretch out
into the three-dimensional space at about 908 to each other,
with obvious consequences for the so-called internal free
volume (IFV) generated.[22,23]
Whereas various successful directed extensions of the
three aromatic wings of the TBTQ system have been report-
ed,[17,18,24–27] threefold (’’linear’’) extension with acene units
has not been achieved yet. By contrast, single-wing exten-
sion was feasible by Diels–Alder methodology involving in
situ-generated TBTQ-based monoaryne and monoisobenzo-
furan analogues at low temperature for trapping with vari-
[a] Dr. E. U. Mughal, J. Eberhard, Prof. Dr. D. Kuck
Department of Chemistry, Bielefeld University,
Universitꢀtsstrasse 25, 33615 Bielefeld (Germany)
E-mail: dietmar.kuck@uni-bielefeld.de
Supporting information for this article is available on the WWW
under http://dx.doi.org/10.1002/chem.201303031.
Chem. Eur. J. 2013, 19, 16029 – 16035
ꢁ 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
16029

1
ous dienes and dienophiles, respectively.[28] In this way, the
dibenzo[2,3]anthrotriquinacene 2 and several higher single-
firmed by using H and 13C NMR spectroscopy and matrix-
G
assisted laser desorption/ionization (MALDI) mass spec-
trometry.
wing-extended congeners including tetracene and pentacene
derivatives were synthesized.[28] Threefold application of this
strategy within the same TBTQ framework appears to be
impeded by the poor solubility of such extended structures
at low temperatures.[17,29] Therefore, we now pursued an al-
ternative, high-temperature strategy involving a threefold
Diels–Alder reaction of TBTQ-based ortho-quinodime-
thanes with suitable dienophiles.[30] Under such conditions,
the solubility of even threefold-extended intermediates and
products was expected to be sufficiently enhanced. In this
way, we developed an access to TBTQ analogues bearing
three linear acene wings as derivatives of the parent tris-
2,7-Dihydrobenzo[c]thiophene-S,S-dioxides are known to
be valuable precursors for in situ-generation of ortho-quino-
dimethanes for subsequent [4+2] cycloaddition reactions.[30]
In this vein, TBTQ-tris-sulfone 5 was found to be a suitable
precursor of the triquinacene-based tris-ortho-quinodime-
thane 6. Although the intermediacy of 6 remains hypotheti-
cal, indeed, thermolysis of tris-sulfone 5 gave rise to three-
fold Diels–Alder reactions with quinones (Scheme 2). Thus,
heating compound 5 in 1,2,4-trichlorobenzene in the pres-
ence of an excess of para-benzoquinone gave a product mix-
ture which, after treatment with activated manganese diox-
ide in 1,4-dioxane under reflux,[31] furnished the tris-1,4-an-
thraquinone 7 in moderate yield. Likewise, thermolysis of 5
in the presence of 1,4-naphthoquinone under similar condi-
tions gave a mixture of partially and fully aromatized prod-
ucts, which were subjected to chromatography before aro-
matization. Careful chromatographic purification afforded
tris(tetracene)quinone 8 in good yield. The C3v-symmetrical
molecular structure of these first TBTQ derivatives bearing
a quinone unit in each of the three wings was confirmed by
ACHTUNGTRENNUNG(tetraceno)triquinacene B. The synthesis and photophysical
properties of these new oligoacenes will be reported here.
Results and Discussion
In view of the poor solubility of some extended TBTQ de-
rivatives,[17a] the sixfold chloromethylated 4b,8b,12b-triprop-
yl-12d-methyl congener 3 was chosen as a starting point
(Scheme 1).[25c] According to a procedure reported previous-
mass spectrometry and H and 13C NMR spectroscopy. For
example, the H NMR spectrum of 8 exhibits two distinct
1
1
6H singlet resonances for the three inner naphthalene units.
The efficient threefold extension of the TBTQ framework
in the case of compound 8 allowed us to synthesize the tris-
AHCTUNGTREG(NNNU tetraceno)triquinacene hydrocarbons 9 and 10 (Scheme 2).
Quinone 8 was reduced to the corresponding threefold 5,12-
dihydrotetracene-5,12-diol by the use of sodium borohydride
in THF/methanol.[20d] The hexa-alcohol was not isolated in
pure form but reduced further with stannous chloride in
aqueous hydrochloric acid[7a] to give tris(2,3-tetraceno)tri-
quinacene 9 as a yellow/orange solid in a remarkably good
yield. We were pleased to find that, in line with expectation,
this triply wing-extended TBTQ hydrocarbon was readily
soluble in various organic solvents and remarkably stable in
solution and in the solid state for several weeks in the ab-
sence of oxygen.
Sixfold addition of phenyllithium to trisquinone 8 in THF/
benzene at 608C gave a mixture of stereoisomeric hexa-al-
cohols that, after purification by column chromatography
and subsequent reduction with stannous chloride in HCl/
H2O/THF, gave the corresponding hexaphenyl-substituted
tris(2,3-tetraceno)triquinacene 10 as an orange/red solid in
good yield. Again in line with expectation, hydrocarbon 10
was found to be well-soluble in usual organic solvents. The
identity of hydrocarbons 9 and 10 was confirmed by NMR
spectroscopy and MALDI MS. Use of single-electron oxi-
dant matrices {tetracyanoquinodimethane (TCNQ) or trans-
2-[3-(4-tert-butylphenyl)-2-methyl-2-propenylidene]malono-
nitrile (DCTB)} gave rise to the molecular radical cations in
high relative abundance and the NMR spectra nicely con-
firmed the expected molecular C3v symmetry of these C68H54
and C104H78 hydrocarbons.
Scheme 1. Synthesis of the TBTQ-based trisulfone 5 as a precursor of
TBTQ-based diene intermediates, such as the hypothetical tris(ortho-qui-
nodimethano)triquinacene 6.
ly,[25a] treatment of 3 with sodium sulfide under phase-trans-
fer catalysis (PTC) conditions furnished the corresponding
threefold thioether 4 in moderate yield. Threefold oxidation
to the corresponding tris-sulfone 5 was achieved by use of
an excess of acetic acid and hydrogen peroxide in dichloro-
methane as a co-solvent at elevated temperature (608C),
producing compound 5 in excellent yield. The structural
identity and molecular C3v-symmetry of 4 and 5 was con-
16030
www.chemeurj.org
ꢁ 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2013, 19, 16029 – 16035

Tris(tetraceno)triquinacenes
FULL PAPER
structured absorption bands in
the UV region and a second set
of absorption bands in the Vis
region of the electromagnetic
spectrum (Figures 2 and 3). The
Vis absorption bands of the
TBTQ trisquinones 7 and 8 are
broad and almost unstructured.
In line with its more extended
chromophore, the Vis absorp-
tion of 8 is redshifted by Dn˜ =
454 cmÀ1. In contrast to the tris-
quinones, the tris(tetraceneno)-
triquinacenes 9 and 10 show the
typical structured band shape of
higher acenes in the visible
region with lowest-energy tran-
sitions at 492 and 512 nm, re-
spectively (Figure 3). The ab-
sorption of 9 is close to that of
simple 2,3-dialkyltetracenes.[20c]
Also, the redshift by Dn˜ =
794 cmÀ1 for 10 compared with
9 is similar to that reported for
5,12-diphenyltetracene
and
parent tetracene (Dn˜ =770–
810 cmÀ1,
solvent-depending
values).[33a,34]
The trisquinones
7 and 8
were found to be almost non-
fluorescent but to show broad,
unstructured emission bands,
with the emission of the larger
chromophore being strongly
redshifted (Figure 2). The emis-
sion is independent of the exci-
tation wavelength and the emis-
Scheme 2. Synthesis of the triquinacene-based trisquinones 7 and 8 and of the tris(tetraceno)triquinacenes 9
and 10.
The fusion of the planar 5,12-diphenyltetracene units to
the bowl-shaped triquinacene core in 10 is particularly note-
worthy in view of restricted internal rotation. Recently, the
aryl
barrier towards rotation about the Caryl
bonds in vari-
À
C
ous 9,10-arylanthracenes was determined to be ꢀ21 kcal
molÀ1.[32] Actually, the H NMR spectrum of 10 exhibits two
1
distinct doublet resonances for the ortho protons of the six
phenyl groups, which remain separated even at 1008C (see
the Supporting Information). The 13C NMR spectrum of 10
also indicates apparently static phenyl groups. Thus, obser-
vation of a strongly hindered rotation in 10 represents a grat-
ifying spin-off of the fact that the bent TBTQ core renders
the two otherwise equivalent surfaces of anthracene and
higher acene units stereochemically distinct.
The optical properties of the trisACTHUNTGRNEUNG(aceno)triquinacene de-
Figure 2. UV/Vis absorption and emission spectra of trisquinones 7 (top)
and 8 (bottom) recorded in CH2Cl2. Absorption, solid black lines (left ab-
solute scale); fluorescence, gray lines (right scale); and fluorescence exci-
tation, dashed lines (right scale). Emission spectroscopy: lexc. =316 nm,
excitation: lmonitor =465 (7) and 525 nm (8).
rivatives 7–10 were investigated by steady-state UV/Vis ab-
sorption and fluorescence spectroscopy in dichloromethane
solution (see the Supporting Information for explicit data).
All compounds were found to exhibit strong and slightly
Chem. Eur. J. 2013, 19, 16029 – 16035
ꢁ 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
16031

D. Kuck et al.
Conclusion
Solid-state tetracenes and covalently interconnected bistetr-
AHCTUNGTREGaNNNU cenes with a well-defined spatial alignment of the chromo-
phores are of current interest in photophysical studies,[20,34,35]
and the tris(tetraceno)triquinacenes presented here could
contribute to the field. Owing to the rigid TBTQ core, the
short molecular axis transition dipoles of the tetracene units
lie within the same plane at angles of 608 (Figure 4). This
peculiar, and possibly unique spatial arrangement corre-
sponds to an orientation factor fixed to k2 =1.56.[37]
Figure 3. UV/Vis absorption and emission spectra of tristetracenes 9
(top) and 10 (middle) recorded in CH2Cl2. Absorption, solid black lines
(left absolute scale); fluorescence, gray lines (right scale); and fluores-
cence excitation, dashed lines (right scale). Emission spectroscopy: lexc.
=
461 nm, excitation: lmonitor =524 (9) and 565 nm (10). The magnified Vis
part of the absorption spectra of 9 (d) and 10 (c) are shown in the
bottom image.
sion excitation spectra match (despite instrumental noise)
the absorption spectra. In contrast to the trisquinones, the
triquinacene-based tristetrACTHNUTRGNEUGNacenes 9 and 10 show the typical
Figure 4. Molecular structure, selected structural parameters, and space-
filling model of the tris(2,3-tetraceno)triquinacenes, as calculated by
DFT. The short molecular axis transition dipoles are indicated as bold
arrows. For simplicity, calculations were performed for the bridgehead
tetramethyl derivative.
vibronically structured fluorescence pattern of the higher
acenes (Figure 3). Compared with 9, the hexaphenyl deriva-
te 10 exhibits more strongly redshifted emission bands (500
and 526 nm, respectively; Dn˜ =989 cmÀ1) and also larger
0À0Stokes shifts (Dn˜ =325 and 520 cmÀ1, respectively). The
quantum yields determined for 9 and 10 differ by an order
of magnitude (F=0.02 and 0.21, respectively); however,
such low values are in line with observations made for alky-
lated tetracenes.[20] The significantly higher quantum yield of
10 compared with 9 is also in line with the trend found for
the single chromophores.[33,37]
DFT calculations on the B3LYP/6-31G** level, as similar-
ly applied by others in related studies,[20e,35a] revealed that
the tristetracenes 9 and 10 have their highest occupied mo-
lecular orbitals (HOMOs; A2 symmetry) and lowest occu-
pied molecular orbitals (LUMOs; A1) spread about the
whole C3v-symmetrical molecular framework (see the Sup-
porting Information).[36] Compared with 9, the energies of
the occupied MOs of 10 are slightly increased, whereas the
increase of the LUMO energies is negligible. The frontier
orbitals remain largely unaffected by the phenyl substitu-
tion, but slight differences in electron density distribution
were found for HOMO-1 and HOMO-2 when comparing 9
and 10. The smaller frontier orbital energy gap resulting for
10 is in good agreement with the experimental result.
Experimental Section
Instrumentation and materials: Melting points (uncorrected) were mea-
sured with a Bꢂchi B-540 electrothermal melting point apparatus. IR
spectra were recorded with a Nicolet-380 FTIR spectrometer equipped
with a SmartOrbit diamond ATR cell. UV spectra were recorded with
polytetrafluoroethylene (PTFE)-stoppered fused silica 10 mm pathway
cuvettes on a Perkin–Elmer Lambda 40 UV/Vis double-beam spectrome-
ter. Fluorescence spectra were acquired on a Perkin–Elmer LS-50B spec-
trometer with spectral bandwidth (slit widths) set to 5 or 10 nm for low
fluorescent compounds. Measurements were performed in a thermostated
room at (25Æ1)8C. NMR spectra were measured with a Bruker DRX
500 instrument (1H: 500.1 MHz, 13C: 125.7 MHz, 258C) and referenced
on the (residual proton) solvent signal. Electron ionization (EI) mass
spectra were recorded with a Fisons VG Autospec X double-focusing
mass spectrometer. MALDI measurements were performed with a Voyag-
er-DE MALDI-ToF and DHB, DCTB or TCNQ as matrices. Accurate
mass measurements were performed with the Fisons VG sector-field in-
strument, Autospec X, and a Bruker FT-ICR mass spectrometer, APEX
III (7 T). Dichloromethane, cyclohexane and ethyl acetate were distilled
before use or used in puriss (p.a.) quality (Fischer, VWR) as received.
Reference standards for the relative quantum yield determinations were
9,10-diphenylanthracene (99%, Acros), rubrene (99%, Acros), quinine
(99%, puriss., Fluka), and fluorescein (98%, Merck). All other chemicals
16032
www.chemeurj.org
ꢁ 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2013, 19, 16029 – 16035

Tris(tetraceno)triquinacenes
FULL PAPER
were used as delivered. Manganese dioxide was of ’’activated’’ grade.
1,2,4-trichlorobenzene (p.a. grade) was dried over molecular sieves (4 ꢃ)
and degassed by purging Argon for at least 30 min. Extra-dry tetrahydro-
furan was purchased from Acros Organics. Reactions requiring anhy-
drous conditions were carried out in oven-dried glassware under argon.
All reported yields are yields of the isolated product.
713.2033; m/z calcd for C76H84O12S6Na: 1403.4179 [2M+Na]+; found
1403.4178. Note: Treatment with of 4 with meta-chloroperbenzoic acid in
dichloromethane at ambient temperature produced only mixtures of par-
tially oxidized products.
23b-Methyl-1,4,9,12,17,20-hexaoxo-6b,14b,22b-tri-n-propyl-
1,4,6b,9,12,14b,17,20,22b,23b-decahydro-naphtho
ACHTUNGERTN[NUNG 2,3:f]di(2,3-anthro)-
Photophysical measurements: All measurements were performed in
highly dilute solutions (optical density (O.D.) <0.03, freshly prepared in
dim light). The quantum yields were determined by the relative method
and cross-checked to the following standards: 9,10-diphenylanthracene in
EtOH (aerated), FF =0.95; quinine disulfate in 1 N sulfuric acid (aerat-
ed), FF =0.55, fluorescein in 0.1N aqueous sodium hydroxide (aerated),
FF =0.92.[38] These reference values were reproduced within 10% (rel.
error); therefore, this error limit is also assigned to the values given
above and the validation measurement with rubrene. Excitation was set
to (316Æ1) nm (7, 8) and to (461Æ1) nm (9, 10; rubrene).
N
G
A
5b-Methyl-4b,9b,14b-tri-n-propyl-4b,6,8,9b,11,13,14b,15b-octahydro-
1H,3H-[2]benzothieno[5’,6’:5,6]thieno[3’’,4’’:5’,6’]indeno-
[1’,2’,3’:3,4]pentaleno
fold benzyl chloride 3[25c] (500 mg, 0.710 mmol) and hexadecyltrimethyl-
ammonium bromide (193 mg, 0.532 mmol) in anhydrous dichloromethane
ACHTUNGTRENNUNG[1,2-f][2]benzothiophene (4): A solution of the six-
ACHTUNGTRENNUNG
(50 mL) was stirred under argon while a solution of sodium sulfide nona-
hydrate (768 mg, 3.20 mmol) in demineralized water (50 mL) was added
dropwise through a dropping funnel. The resulting milky mixture was vig-
orously stirred in the dark at ambient temperature for 24 h. The organic
layer was separated and the aqueous layer was extracted with dichloro-
methane (3ꢄ25 mL). The combined organic layers were washed with
brine, dried over anhydrous sodium sulfate, filtered, and concentrated
under reduced pressure. The residue was purified by using column chro-
matography through silica gel (cyclohexane/CH2Cl2 6:1 to 3:1) and fur-
nished the product 4 (146 mg, 35%) as a colorless solid. M.p. 176–
ÀC
ÀC
1
1788C.; H NMR (500 MHz, CD2Cl2): d=7.17 (s, 6H), 4.20 and 4.18 (ex-
tremely narrow AB, J=12.0 Hz, 2ꢄ6H), 2.13 (m, 6H), 1.64 (s, 3H, 12d-
CH3), 1.23–1.17 (m, 6H), 0.96 ppm (t, J=7.5 Hz, 9H); 13C NMR
(125.7 MHz, CD2Cl2): d=147.6 (C), 140.5 (C), 119.4 (CH), 74.0 (C), 66.4
(C), 41.2 (CH2), 37.7 (CH2), 20.8 (CH2), 15.5 (12d-CH3), 15.2 ppm (CH3);
IR (neat): Dn˜ =2954, 2909, 2866, 1479, 1432, 1034, 906, 728, 615 cmÀ1; MS
ACHTUNGTNER[NUNG 2,3:f]di(2,3-tetraceno)-
(EI, 70 eV): m/z (%), 594 (9, [M]+ ), 551 (100), 465 (2), 275.6 (7,
C
[MÀC3H7]2+); MS (ESI+, CH3CN, AgBF4): m/z: 701 (100, [M+107Ag]+),
702 (35), 703 (98), 704 (64), 705 (24); HRMS (ESI+, CH3CN): m/z calcd
for C38H42S3107Ag: 701.1494 [M+107Ag]+; found: 701.1505. Note: Several
attempts carried out under varied conditions did not give higher yields.
Tristhioether 4 was found to be highly light- and air-sensitive; therefore,
the reaction, work-up, and chromatographic purification were performed
by carefully excluding light and oxygen.
15b-Methyl-4b,9b,14b-tri-n-propyl-4b,6,8,9b,11,13,14b,15b-octahydro-
1H,3H-[2]benzothieno[5’,6’:5,6]thieno[3’’,4’’:5’’,6’]indeno-
[1’,2’,3’:3,4]pentalenoACHTUNGTRENNUNG[1,2-f][2]benzothiophene-S,S,S’,S’,S’’,S’’-hexoxide
+
C
(5): A solution of compound 4 (110 mg, 0.185 mmol) in dichloromethane
(2–3 mL) was added to glacial acetic acid (6 mL) followed by slow addi-
tion of hydrogen peroxide (30%; 2 mL) at ambient temperature. The re-
sulting mixture was stirred at 608C for 20 h. After cooling to room tem-
perature, the mixture was carefully added to a saturated solution of
sodium bicarbonate to neutralize the excess acid. The aqueous suspen-
sion was then extracted with ethyl acetate (3ꢄ15 mL). The combined or-
ganic layers were washed with brine, dried over anhydrous sodium sul-
fate, filtered, and concentrated under reduced pressure to afford the
product 5 (110 mg, 86%) as a colorless solid (note that subsequent pre-
cipitation with chloroform/n-pentane could be helpful to remove associat-
ÀC
ÀC
1
ed solvents). M.p.>3408C; H NMR (500 MHz, CDCl3): d=7.19 (s, 6H),
4.35 and 4.30 (AB, J=16.0 Hz, 2ꢄ6H), 2.12 (m, 6H), 1.63 (s, 3H, 12d-
CH3), 1.20–1.13 (m, 6H), 0.95 ppm (t, J=7.5 Hz, 9H); 13C NMR
(125.7 MHz, CDCl3): d=148.5 (C), 130.7 (C), 121.0 (CH), 72.0 (C), 67.2
(C), 56.9 (CH2), 40.8 (CH2), 20.4 (CH2), 15.1 (12d-CH3), 15.0 ppm (CH3);
IR (neat): Dn˜ =2955, 2928, 2869, 1480, 1310, 1225, 1156, 1125, 751,
576 cmÀ1
; MS (MALDI+, DHB, CH2Cl2/MeOH): m/z: 713 (100,
[M+Na]+), 729 (70, [M+K]+); HRMS (MALDI+, DHB, CH2Cl2/
MeOH): m/z calcd for C38H42O6S3Na: 713.2035 [M+Na]+; found
Chem. Eur. J. 2013, 19, 16029 – 16035
ꢁ 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
16033

D. Kuck et al.
washed with brine (2ꢄ15 mL), dried over anhydrous sodium sulfate, fil-
tered, and then concentrated under reduced pressure. The residue was
purified by flash column chromatography through silica gel (cyclohexane/
CH2Cl2 9:1) to furnish the product 9 (64 mg, 70%) as a yellow-orange
solid. M.p. decomposes>2508C; 1H NMR (500 MHz, CD2Cl2): d=8.75
(s, 6H), 8.66 (s, 6H), 8.24 (s, 6H), 7.99 and 7.38 (AA’BB’, 2ꢄ6H), 2.62
(m, 6H), 1.90 (s, 3H, 12d-CH3), 1.42–1.47 (m, 6H), 1.08 ppm (t, J=
7.5 Hz, 9H); 13C NMR (125.7 MHz, CD2Cl2): d=149.1 (C), 132.1 (C),
131.3 (C), 130.0 (C), 128.1 (CH), 125.9 (CH), 125.7 (CH), 124.9 (CH),
121.5 (CH), 72.7 (C), 66.6 (C), 42.7 (CH2), 20.5 (CH2), 15.7 (12d-CH3),
15.0 ppm (CH3); IR (neat): Dn˜ ==2953, 2917, 2848, 1454, 1280, 1260,
1156, 1070, 884, 748 cmÀ1; UV/Vis (CH2Cl2): labs (e)=297 (118), 306
(104), 432 (4.64), 460 (6.94), 492 nm (5.81 10À3 LmolÀ1 cmÀ1); MS
Acknowledgements
Financial support by the Deutsche Forschungsgemeinschaft (DFG, KU
663/16-1) is gratefully acknowledged. We also thank the regional comput-
ing center of the University of Cologne (RRZK) for providing the CPU
time on the DFG-funded supercomputer ’’CHEOPS’’ and for support.
[1] a) R. Mondal, R. M. Adhikari, B. K. Shah, D. C. Neckers, Org. Lett.
2007, 9, 2505–2508; b) E. Clar, Polycyclic Hydrocarbons, Vol. 1, 2,
Academic Press, London, New York, 1964; c) R. G. Harvey, Poly-
cyclic Aromatic Hydrocarbons, Wiley-VCH, New York, 1997.
[2] a) R. Rieger, K. Mꢂllen, J. Phys. Org. Chem. 2010, 23, 315–325;
b) D. D. L. Chung, J. Mater. Sci. 2002, 37, 1475–1489.
(MALDI+, TCNQ, MeCN/THF): m/z: 870 (80, [M]+ ), 871 (100,
C
[M+H]+), 827 (60) [MÀC3H7]+, 828 (65) [M+HÀC3H7]+
;
HRMS
870.4220
[3] S. Iijima, T. Ichihashi, Nature 1993, 363, 603–605.
C
:
[4] a) J. E. Anthony, Chem. Rev. 2006, 106, 5028–5048; b) M. Bendikov,
F. Wudl, D. F. Perepichka, Chem. Rev. 2004, 104, 4891–4945; c) J. E.
Anthony, Angew. Chem. 2008, 120, 460–492; Angew. Chem. Int. Ed.
2008, 47, 452–483.
[5] a) G. K. R. Senadeera, P. V. V. Jayaweera, V. P. S. Perera, K. Tenna-
kone, Solar Energy 2002, 73, 103–108; b) C. Videlot, D. Fichou, F.
Garnier, J. Chim. Phys. Phys.-Chim. Biol. 1998, 95, 1335–1338;
c) S. C. Dahlberg, M. E. Musser, J. Chem. Phys. 1979, 71, 2806–
2810.
(MALDI+, DCTB, CH2Cl2/MeOH): m/z calcd for C68H54
[M]+ ; found: 870.4218.
30b-Methyl-5,10,15,20,25,30-hexaphenyl-7b,17b,27b-tri-n-propyl-
7b,17b,27b,30b-tetrahydroanthro[2,3:f]di(2,3-tetraceno)-
[2,3:4,5]pentaleno[1,6:ab]indene (10): A solution of compound 8 (75 mg,
0.078 mmol) in anhydrous tetrahydrofuran/benzene (1:1, 10 mL) was
stirred while solution of phenyllithium in di-n-butyl ether (1.9m)
C
AHCTUNGTRENNUNG
A
ACHTUNGTRENNUNG
a
(4.21 mL, 8.00 mmol) was added dropwise at 08C under argon. The reac-
tion mixture was heated to 608C (oil bath temperature) for 20 h. After
careful hydrolysis, the resulting mixture was extracted with diethyl ether
(3ꢄ15 mL). The combined organic layers were washed with brine and
dried over sodium sulfate, filtered, and then concentrated under reduced
pressure. The residue was subjected to column chromatography through
silica gel (cyclohexane/EtOAc 9:1 to 3:1) to furnish a solid material,
which was re-dissolved in tetrahydrofuran (12 mL). This solution was de-
gassed by purging with argon for 15 min. Then, a saturated solution of
tin(II) chloride (4.0 mL) in 18% aqueous hydrochloric acid was added at
room temperature. The resulting solution was stirred for 1 h under argon
and in the absence of light. After completion of the reaction (monitored
by TLC), the mixture was quenched with water and extracted with dieth-
yl ether (3ꢄ15 mL). The combined organic layers were washed with
brine (2ꢄ15 mL), dried over anhydrous sodium sulfate, filtered, and then
concentrated under reduced pressure. The residue was purified by
column chromatography through silica gel (cyclohexane/CH2Cl2 9:1) to
furnish the product 10 (69 mg, 66%) as an orange/red solid. M.p.
>2508C (decomp.); 1H NMR (500 MHz, CD2Cl2): d=8.30 (s, 6H), 7.88
(s, 6H), 7.72–7.80 (m, 18), 7.63 and 7.24 (AA’BB’, 2ꢄ6H), 7.60 (m, 6H),
7.53 (m, 6H), 2.35 (bs, 6H), 1.70 (s, 3H, 12d-CH3), 1.15–1.25 (m, 6H),
0.90 ppm (t, J=7.5 Hz, 9H); 1H NMR (500 MHz, C2D2Cl4): d=8.22 (s,
6H), 7.80 (s, 6H), 7.61–7.64 (m, 18), 7.55 and 7.16 (AA’BB’, 2ꢄ6H),
7.48–7.50 (m, 6H), 7.39–7.41 (m, 6H), 2.28 (bs, 6H), 1.61 (s, 3H, 12d-
CH3), 1.15–1.20 (m, 6H), 0.84 ppm (t, J=7.5 Hz, 9H); 13C NMR
(125.7 MHz, CD2Cl2): d=149.0 (C), 139.4 (C), 136.7 (C), 131.7 (C), 131.5
(CH), 131.4 (CH), 129.1 (C), 128.7 (C), 128.6 (CH), 128.5 (CH), 127.4
(CH), 126.8 (CH), 125.1 (CH), 124.5 (CH), 121.6 (CH), 72.3 (C), 66.4
(C), 42.7 (CH2), 20.2 (CH2), 15.2 (12d-CH3), 14.9 ppm (CH3); IR (neat):
Dn˜ =2955, 2924, 2867, 1455, 1440, 1392, 1261, 1072, 900, 746, 701,
669 cmÀ1; UV/Vis (CH2Cl2): labs (e)=308 (127), 315 (125), 449 (6.70), 478
(12.5), 512 nm (11.6 10À3 LmolÀ1 cmÀ1); MS (MALDI+, DCTB, CH2Cl2):
[6] a) J. E. Anthony, D. L. Eaton, S. R. Parkin, Org. Lett. 2002, 4, 15–
18; b) H. E. Katz, Z. Bao, S. L. Gilat, Acc. Chem. Res. 2001, 34,
359–369; c) M. L. Tang, T. Okamoto, Z. Bao, J. Am. Chem. Soc.
2006, 128, 16002–16003.
[7] a) S. A. Odom, S. R. Parkin, J. E. Anthony, Org. Lett. 2003, 5, 4245–
4248; b) L. C. Picciolo, H. Murata, Z. H. Kafafi, Appl. Phys. Lett.
2001, 78, 2378–2380; c) M. A. Wolak, B. Jang, L. C. Palilis, Z. H.
Kafafi, J. Phys. Chem. B 2004, 108, 5492–5499.
[8] a) C. D. Dimitrakopoulos, P. R. L. Malenfant, Adv. Mater. 2002, 14,
99–117; b) A. R. Murphy, J. M. J. Frꢅchet, P. Chang, J. Lee, V. Sub-
ramanian, J. Am. Chem. Soc. 2004, 126, 1596–1597.
[9] R. Schmidt, S. Gçttling, D. Leusser, D. Stalke, A. M. Krause, F.
Wꢂrthner, J. Mater. Chem. 2006, 16, 3708–3714.
[10] F. Valiyev, W. S. Hu, H. Y. Chen, M. Y. Kuo, I. Chao, Y. T. Tao,
Chem. Mater. 2007, 19, 3018–3026.
[11] a) C. D. Sheraw, T. N. Jackson, D. L. Eaton, J. E. Anthony, Adv.
Mater. 2003, 15, 2009–2011; b) M. D. Curtis, J. Cao, J. W. Kampf, J.
Am. Chem. Soc. 2004, 126, 4318–4328.
[12] a) E. Clar, Chem. Ber. 1939, 72B, 2137–2139; b) H. Angliker, E.
Rommel, J. Wirz, Chem. Phys. Lett. 1982, 87, 208–212.
[13] M. Watanabe, K. Y. Chen, Y. J. Chang, T. J. Chow, Acc. Chem. Res.
2013, 46, 1606–1615.
[14] a) D. Kuck, Angew. Chem. 1984, 96, 515–516; Angew. Chem. Int.
Ed. Engl. 1984, 23, 508–509; b) D. Kuck, T. Lindenthal, A. Schuster,
Chem. Ber. 1992, 125, 1449–1460; c) D. Kuck, A. Schuster, B. Ohl-
horst, V. Sinnwell, A. de Meijere, Angew. Chem. 1989, 101, 626–
628; Angew. Chem. Int. Ed. Engl. 1989, 28, 595–597; d) D. Kuck, E.
Neumann, A. Schuster, Chem. Ber. 1994, 127, 151–164; e) T. X.
Zhang, L. Zhou, X. P. Cao, D. Kuck, Chin. J. Org. Chem. 2007, 27,
946–957.
[15] G. Markopoulos, L. Henneicke, J. Shen, Y. Okamoto, P. G. Jones, H.
Hopf, Angew. Chem. 2012, 124, 13057–13060; Angew. Chem. Int.
Ed. 2012, 51, 12884–12887.
[16] D. Kuck, Naturwiss. Rundsch. 2013, 66, 138–139.
[17] a) D. Kuck, Chem. Rev. 2006, 106, 4885–4925; b) D. Kuck, Pure
Appl. Chem. 2006, 78, 749–775.
m/z: 1327 (95; merged peaks of [M]+ and 13C1À[M]+ ), 1359 (100;
C
C
merged peaks of [M]+ and 13C1À[M]+ of O2 adduct), 1391 (60; merged
C
C
peaks of [M]+ and 13C1À[M]+ of twofold O2 adduct);[39] HRMS
(MALDI+, DCTB, CH2Cl2/MeOH): m/z calcd for C104H78: 1326.6098
C
C
[18] D. Kuck, A. Schuster, R. A. Krause, J. Tellenbrçker, C. P. Exner, M.
Penk, H. Bçgge, A. Mꢂller, Tetrahedron 2001, 57, 3587–3613.
[19] J. G. Brandenburg, S. Grimme, P. G. Jones, G. Markopoulos, H.
Hopf, M. K. Cyranski, D. Kuck, Chem. Eur. J. 2013, 19, 9930–9938.
[20] a) C. Kitamura, Chem. Rec. 2012, 12, 506–514, and references there-
in; b) C. Kitamura, A. Takenaka, T. Kawase, T. Kobayashi, H.
Naito, Chem. Commun. 2011, 47, 6653–6655, and references there-
in; c) C. Kitamura, T. Ohara, A. Yoneda, T. Kawase, T. Kobayashi,
H. Naito, Chem. Lett. 2011, 40, 58–59; d) C. Kitamura, C. Matsumo-
[M]+ ; found: 1326.6140.
C
Final remark: Further attempts to treat sulfone 5 with other dienophiles,
including dimethyl acetylenedicarboxylate, dimethylfumarate, 1,4-anthra-
quinone and even C60-fullerene, largely failed; very complex mixtures of
products were obtained in these cases. In the case of 1,4-anthraquinone
and dimethylfumarate, the MALDI MS of the crude product mixtures in-
dicated the formation of threefold cycloaddition products in minor
amounts (<5%).
16034
www.chemeurj.org
ꢁ 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2013, 19, 16029 – 16035

Tris(tetraceno)triquinacenes
FULL PAPER
to, A. Yoneda, T. Kobayashi, H. Naito, T. Komatsu, Eur. J. Org.
Chem. 2010, 2571–2575; e) C. Kitamura, Y. Abe, T. Ohara, A.
Yoneda, T. Kawase, T. Kobayashi, H. Naito, T. Komatsu, Chem. Eur.
J. 2010, 16, 890–898.
[29] J. Tellenbrçker, Doctoral Thesis, Bielefeld University, 1999.
[30] a) J. L. Segura, N. Martꢆn, Chem. Rev. 1999, 99, 3199–3246; b) R. L.
Funk, K. P. C. Vollhardt, Chem. Soc. Rev. 1980, 9, 41–61; c) S.
Kotha, D. Kashinath, P. Khedkar, Synthesis 2007, 21, 3357–3360.
[31] a) S. Kotha, P. Khedkhar, J. Org. Chem. 2009, 74, 5667–5670; b) S.
Kotha, P. Khedkhar, Chem. Rev. 2012, 112, 1650–1680.
[32] K. Nikitin, H. Mꢂller-Bunz, Y. Ortin, J. Muldoon, M. J. McGlinchey,
Org. Lett. 2011, 13, 256–259.
[33] a) C. Burgdorff, T. Kircher, H. G. Lçhmannsrçben, Spectrochim.
Acta Part A 1988, 44, 1137–1141; b) C. Burgdorff, H. G. Lçhmanns-
rçben, J. Lumin. 1994, 59, 201–208.
[34] S. T. Roberts, R. E. McAnally, J. N. Mastron, D. H. Webber, M. T.
Whited, R. L. Brutchey, M. E. Thompson, S. E. Bradforth, J. Am.
Chem. Soc. 2012, 134, 6388–6400.
[35] a) A. M. Mꢂller, Y. S. Avlasevich, W. W. Schoeller, K. Mꢂllen, C. J.
Bardeen, J. Am. Chem. Soc. 2007, 129, 14240–14250; b) J. J. Burdett,
C. J. Bardeen, Acc. Chem. Res. 2013, 46, 1312–1320; c) H. Yamaga-
ta, J. Norton, E. Hontz, Y. Olivier, D. Beljonne, J. L. Brꢅdas, R. J.
Silbey, F. C. Spano, J. Chem. Phys. 2011, 134, 204703–204711;
d) S. H. Lim, T. G. Bjorklund, F. C. Spano, C. J. Bardeen, Phys. Rev.
Lett. 2004, 92, 107402–107404.
[21] a) J. Reichwagen, H. Hopf, A. Del Guerzo, C. Belin, H. Bouas-Lau-
rent, J. P. Desvergne, Org. Lett. 2005, 7, 971–974; b) J. Reichwagen,
H. Hopf, J. P. Desvergne, A. Del Guerzo, H. Bouas-Laurent, Synthe-
sis 2005, 20, 3505–3507; c) C. Giansante, G. Raffy, C. Schꢀfer, H.
Rahma, M. T. Kao, A. G. L. Olive, A. Del Guerzo, J. Am. Chem.
Soc. 2011, 133, 316–325.
[22] T. M. Long, T. M. Swager, Adv. Mater. 2001, 13, 601–604.
[23] Y. Jiang, C. F. Chen, Eur. J. Org. Chem. 2011, 6377–6403.
[24] a) J. Tellenbrçker, D. Kuck, Angew. Chem. 1999, 111, 1000–1004;
Angew. Chem. Int. Ed. 1999, 38, 919–922; b) X. P. Cao, D. Barth, D.
Kuck, Eur. J. Org. Chem. 2005, 3482–3488; c) L. Zhou, X. P. Cao,
G. B. Neumann, H. G. Stammler, D. Kuck, Synlett 2005, 2771–2775;
d) B. Bredenkçtter, S. Henne, D. Volkmer, Chem. Eur. J. 2007, 13,
9931–9938; e) P. E. Georghiou, L. Dawe, H. A. Tran, J. Stꢂbe, B.
Neumann, H. G. Stammler, D. Kuck, J. Org. Chem. 2008, 73, 9040–
9047; f) T. Wang, Z. Y. Li, A. L. Xie, X. J. Yao, X. P. Cao, D. Kuck,
J. Org. Chem. 2011, 76, 3231–3238; g) S. Henne, B. Bredenkçtter,
A. A. Dehghan Baghi, R. Schmid, D. Volkmer, Dalton Trans. 2012,
41, 5995–6002.
[36] This is intriguing, because the parent tribenzotriquinacenes, for ex-
ample, the bridgehead tetramethyl derivative of 1, were calculated
[25] a) L. Zhou, T. X. Zhang, B. R. Li, X. P. Cao, D. Kuck, J. Org. Chem.
2007, 72, 6382–6389; b) E. U. Mughal, D. Kuck, Org. Biomol. Chem.
2010, 8, 5383–5389; c) E. U. Mughal, D. Kuck, Eur. J. Org. Chem.
2012, 3416–3423.
[26] a) M. Harig, B. Neumann, H. G. Stammler, D. Kuck, Eur. J. Org.
Chem. 2004, 2381–2397; b) Y. Kirchwehm, A. Damme, T. Kupfer,
H. Braunschweig, A. Krꢂger, Chem. Commun. 2012, 48, 1502–1504;
c) J. Vile, M. Carta, C. G. Bezzu, N. B. McKeown, Polym. Chem.
2011, 2, 2257–2260; d) R. Saravanakumar, G. Markopoulos, L. G.
Bahrin, P. G. Jones, H. Hopf, Synlett 2013, 24, 453–456.
to have a nonsymmetrical electron-density distribution in the
HOMOs and LUMOs (see the Supporting Information).
[37] a) R. E. Dale, J. Eisinger, W. E. Blumberg, Biophys. J. 1979, 26,
161–193; b) B. W. van der Meer, Rev. Mol. Biotechnol. 2002, 82,
181–196; c) G. D. Scholes, Annu. Rev. Phys. Chem. 2003, 54, 57–87.
[38] a) S. Fery-Forgues, D. Lavabre, J. Chem. Educ. 1999, 76, 1260–1264;
b) A. M. Brouwer, Pure Appl. Chem. 2011, 83, 2213–2228.
[39] The measurement is accompanied by the addition of dioxygen to
compound 11 to produce endoperoxides, the molecular ions of
which appeared at m/z 1359 and m/z 1391, respectively.
[27] H. Langhals, M. Rauscher, J. Strꢂbe, D. Kuck, J. Org. Chem. 2008,
73, 1113–1116.
[28] W. X. Niu, E. Q. Yang, Z. F. Shi, X. P. Cao, D. Kuck, J. Org. Chem.
2012, 77, 1422–1434.
Received: August 1, 2013
Published online: October 14, 2013
Chem. Eur. J. 2013, 19, 16029 – 16035
ꢁ 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
16035