Selective oxidative cyclization by FeCl3 in the construction of 10H-indeno[1,2-b]triphenylene skeletons in polycyclic aromatic hydrocarbons

Article abstract of DOI:10.1021/jo0609172

A novel family of polycyclic aromatic hydrocarbons of various shapes based on the 10H-indeno[1,2-b]-triphenylene skeleton has been synthesized via a reaction sequence of Diels-Alder reaction, decarbonylation, followed by an oxidative cyclization. In parti

Full text of DOI:10.1021/jo0609172

Selective Oxidative Cyclization by FeCl3 in the Construction of
10H-Indeno[1,2-b]triphenylene Skeletons in Polycyclic Aromatic
Hydrocarbons
Yan Zhou, Wen-Jun Liu, Wei Zhang, Xiao-Yu Cao, Qi-Feng Zhou, Yuguo Ma,* and
Jian Pei*
The Key Laboratory of Bioorganic Chemistry and Molecular Engineering and the Key Laboratory of
Polymer Chemistry and Physics of Ministry of Education, College of Chemistry and Molecular
Engineering, Peking UniVersity, Beijing 100871, China
jianpei@pku.edu.cn; ygma@pku.edu.cn
ReceiVed May 3, 2006
A novel family of polycyclic aromatic hydrocarbons of various shapes based on the 10H-indeno[1,2-b]-
triphenylene skeleton has been synthesized via a reaction sequence of Diels-Alder reaction, decarbo-
nylation, followed by an oxidative cyclization. In particular, the reaction conditions for regioselective
oxidative cyclization promoted by FeCl3 are investigated, and this reaction is employed as an effective
method to afford the above molecules under mild conditions. Their photophysical properties in dilute
solution are also reported.
Introduction
applications in the construction of fullerenes and carbon
nanotubes and in the assembly of supramolecular architectures,
PAHs have been extensively used in electronic and optoelec-
tronic devices, such as photovoltaic cells, liquid crystal displays,
organic light-emitting diodes (OLEDs), and organic field effect
transistors (OFETs).1 Studies on these molecular-defined model
compounds also enrich the chemistry of PAHs.2
Since both the molecular size and the shape of PAHs play
very important roles on their electronic properties, energetics,
and reactivity, it is necessary to design and synthesize PAHs
of diverse structures for systematic investigation of their
structure-property relationships and the tuning of molecular
properties for specific applications.1,3 Moreover, the construction
of novel nanosized, soluble, planar or helical polycyclic aromatic
compounds is of great interest. Thus, elegant synthetic ap-
proaches to PAHs with diverse sizes and shapes have been
developed.3,4 In particular, a multibond oxidative coupling
In the past decades, polycyclic aromatic hydrocarbons (PAHs)
with well-defined geometry and desired electronic properties
have attracted considerable attention. In addition to their
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10.1021/jo0609172 CCC: $33.50 © 2006 American Chemical Society
Published on Web 08/01/2006
6822
J. Org. Chem. 2006, 71, 6822-6828

Construction of 10H-Indeno[1,2-b]triphenylene Skeletons
SCHEME 1
reaction using FeCl3 has been explored as an efficient meth-
odology in the construction of novel PAHs, including hexa-
peri-hexabenzocoronene (HBC), sulfur-containing polycyclic
aromatics, as well as heterosuperbenzenes.4 However, to our
best knowledge, no selectivity was observed with such oxidative
cyclization in the construction of larger HBC derivatives.
Herein, we report the synthesis of a novel class of PAHs with
various shapes, in which the 10H-indeno[1,2-b]triphenylene
moiety served as the basic skeleton. We developed a facile,
efficient, and regioselective approach to such molecules via a
reaction sequence of Sonogashira cross-coupling, Diels-Alder
reaction, decarbonylation, and an oxidative cyclization by FeCl3.
Additionally, fluorene units were incorporated as the basic
building block for these PAHs because fluorene analogues and
polyfluorenes have exhibited desired properties for applications
in optoelectronic devices.5 Due to the presence of a number of
alkyl substituents, the accomplished PAHs exhibit good solubil-
ity in common organic solvents.
Results and Discussion
Synthesis. Scheme 1 illustrates the synthetic route to dimer
3. The Sonogashira coupling reaction of 9,9-dihexyl-2-iodo-
fluorene with phenylacetylene in the presence of Pd catalyst
afforded 1 as a white solid in high yield. The Diels-Alder
reaction of compound 1 with 2,5-diethyl-3,4-diphenylcyclopen-
tadienone followed by decarbonylation in refluxed mesitylene
produced 2 in 95% yield. It is noteworthy that the oxidative
cyclization mediated by FeCl3 (8 equiv of FeCl3 per C-C bond
formation)4 afforded dimer 3 rather than the expected 4. The
formation of 3 requires not only the cyclization to afford the
expected 10H-indeno[1,2-b]triphenylene skeleton but also an
intermolecular dimerization coupling between the fluorene units.
We were not able to isolate any compound 4. At 0 °C, we did
not observe polymerization or other compounds even when an
excess amount of FeCl3 (20 equiv per C-C bond formation)
was used.
SCHEME 2
As shown in Scheme 2, to better understand the process of
the oxidative cyclization, we applied the same reaction condi-
tions to 9′,9′-dihexyl-2′-fluorenylacetylene 5.4i Compound 5 and
2,5-diethyl-3,4-diphenylcyclopentadienone underwent a Diels-
Alder reaction followed by decarbonylation to produce 6. In
comparison with 2, the phenyl ring in close proximity to the
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2005, 70, 3645-3653. (j) Pei, J.; Zhang, W.-Y.; Mao, J.; Zhou, X.-H.
Tetrahedron Lett. 2006, 47, 1551-1554.
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Liu, T.-L.; Hung, W.-Y.; Lin, Y.-T.; Wong, K.-T.; Chen, R.-T.; Chen, Y.-
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6987-6995.
adjacent fluorenyl moiety was absent in compound 6 so that
the 10H-indeno[1,2-b]triphenylene skeleton could not be formed
using FeCl3 as the oxidant. To assess the specificity of the
oxidative cyclization under such conditions, compound 6 was
subjected to FeCl3 oxidation and compound 7 was produced
and isolated in 50% yield. For compound 6, we knew that the
10H-indeno[1,2-b]triphenylene skeleton could not be constructed
using FeCl3 oxidant. We also employed a larger excess of FeCl3
(20 equiv per C-C bond formation) to drive the reaction to
completion without polymerization and chlorization. The FeCl3
oxidation has ever been employed to prepare polyfluorene from
fluorene derivatives at room temperature.6 These experimental
results suggest that the FeCl3 oxidative coupling might be an
effective method for the preparation of oligofluorene derivatives.
In addition, as shown in Schemes 1 and 2, we did not observe
any products from the C-C bond formation between the
benzene rings that are not part of the fluorene units. This result
J. Org. Chem, Vol. 71, No. 18, 2006 6823

Zhou et al.
SCHEME 3
in a good yield (94%), as illustrated in Scheme 5. For this two-
fluorene-terminated compound 16 from compound 15, it was
surprising that we did not observe any dimerization, such as in
the cyclizations of 3 and 7, or polymerization at 0 °C. This
might be due to the lower cation activity caused by the high
delocalization of the whole conjugated structure and the steric
hindrance within the structure of 15. This may allow us to
prepare even larger molecules with interesting structures through
the formation of multiple C-C bonds utilizing oligofluorenyl-
acetylene derivatives.
To demonstrate generality of the method, we examined
whether extended fluorenyl moieties would affect the cyclization
efficiency. We prepared model compound 18 through Diels-
Alder reaction and decarbonylation from 2,7-bis[2′-(9′′,9′′-
dihexyl-2′′-fluorenylethynyl)]-9,9-dihexylfluorene (17) (as shown
in Scheme 6). Similar oxidative conditions effectively provided
the double-cyclized product 19 in 61% yield. This result suggests
that the current protocol may provide an effective method for
the preparation of helical polycyclic aromatics.
is quite different from the preparation of hexa-peri-hexaben-
zocoronene (HBC) derivatives.4a,b,i
We then optimized the conditions of this oxidative cyclization
by examining the amount of FeCl3 added as well as the reaction
temperature. It was found that even in the presence of an excess
amount of FeCl3 (more than 20 equiv per C-C bond formation),
no chlorinated byproducts were produced at 0 °C.4b,i Nonethe-
less, the cyclization was completed in less than 10 min.
However, as shown in Scheme 3, when a bromide substituent
was introduced at the C7 position of the fluorene unit, the
formation of the 10H-indeno[1,2-b]triphenylene system was not
achieved, and we speculated that this might be due to the
deactivation effect of the bromide group. Upon introducing a
methoxy substituent to enhance the electron density of the
phenylene ring, compound 10 was obtained by the oxidative
cyclization of 9 in 30% yield.
With these results in hand, we utilized the oxidative cycliza-
tion protocol described above to construct larger systems via
the fluorenyl-phenyl or fluorenyl-fluorenyl carbon-carbon
bond formation. From the corresponding iodide compounds, we
prepared 9,9-dihexyl-2,7-bis(2-phenylethynyl)fluorene (11) and
bis(9,9-dihexyl-2-fluorenyl)acetylene (14) through the Sono-
gashira coupling reaction.4i,7 As shown in Scheme 4, the Diels-
Alder reaction of 9,9-dihexyl-2,7-bis(2-phenylethynyl)fluorene
with 2,5-diethyl-3,4-diphenylcyclopentadienone followed by
decarbonylation afforded 12 in 68% yield. A double cyclization
of 12 by the oxidation of FeCl3 afforded 13 in an optimal yield
of 95%. Compound 16 was also obtained via a similar procedure
All herein prepared polycyclic aromatic hydrocarbons readily
dissolved in common organic solvents, such as CHCl3 and
chlorobenzene, and were characterized by standard spectroscopic
measurements. The identity and the purity of all new compounds
were confirmed by 1H and 13C NMR spectra, MALDI-TOF or
1
EI mass spectrum, as well as elemental analysis. H NMR
spectra in CDCl3 of all compounds show sharp and well-defined
signals at room temperature. For all compounds, the presence
1
of signals at 0.4-0.7 ppm was observed in H NMR spectra.
These signals were assigned to methylene groups of the hexyl
substituents, and they were more upfield than those of the methyl
group and the methylene groups in other structures. Such
behaviors had actually also been observed by us and by others
in the extensively investigated 9,9-dialkylfluorene moiety.8 For
1
all cyclized compounds, in the aromatic range of H NMR
spectra, both sharp singlet signals belonging to the triphenylene
system moved downfield to 8.3 ppm from less than 8.0 ppm
after the cyclization. Spectroscopic measurements also confirm
the C2 symmetry of these polycyclic molecules. Likely due to
the hexyl substituents,9 fused compounds 13 and 16 with such
large planar π-systems did not exhibit concentration-dependent
chemical shifts in the 1H NMR spectra, although their favorable
cofacial interactions could induce aggregation within the system.
SCHEME 4
6824 J. Org. Chem., Vol. 71, No. 18, 2006

Construction of 10H-Indeno[1,2-b]triphenylene Skeletons
SCHEME 5
SCHEME 6
Photophysical Properties. The basic photophysical properties
of these 10H-indeno[1,2-b]triphenylene derivatives in dilute
THF solutions (10-5 mol L-1) were first investigated, and their
absorption spectra are shown in Figure 1. Table 1 summarizes
the photophysical properties of these compounds. The typical
absorption feature of the triphenylene moiety was at ∼250-
260 nm.10 For most of our compounds studied, a slight red shift
was observed in their absorption spectra (270 nm for 3, 276
nm for 10, 276 nm for 13, and 281 nm for 16), except for
compound 7 because no 10H-indeno[1,2-b]triphenylene skeleton
existed in this compound structure. We also observed the strong
absorption behaviors at ∼300-310 nm for another five com-
(8) (a) Ranger, M.; Leclerc, M. Macromolecules 1999, 32, 3306-3313.
(b) Destri, S.; Pasini, M.; Botta, C.; Porzio, W.; Bertini, F.; Marchio`, L. J.
Mater. Chem. 2002, 12, 924-933. (c) Alder, R. W.; Anderson, K. R.;
Benjes, P. A.; Burts, C. P.; Koutentis, P. A.; Orpen, A. G. J. Chem. Soc.,
Chem. Commun. 1998, 309-310. (d) Ranger, M.; Be´langer-Garie´py, F.;
Leclerc, M. Acta Crystallogr., Part C 1998, 54, 799-805. (e) Cao, X.-Y.;
Liu, X.-H.; Zhou, X.-H.; Zhang, Y.; Jiang, Y.; Cao, Y.; Cui, Y.-X.; Pei, J.
J. Org. Chem. 2004, 69, 6050-6058.
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Am. Chem. Soc. 2003, 125, 9944-9945. (b) Cao, X.-Y.; Zhang, W.-B.;
Wang, J.-L.; Zhou, X.-H.; Lu, H.; Pei, J. J. Am. Chem. Soc. 2003, 125,
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J. Org. Chem, Vol. 71, No. 18, 2006 6825

Zhou et al.
FIGURE 2. The emission spectra of new compounds in dilute THF
solutions (10-5 mol L-1) at room temperature.
FIGURE 1. The absorption spectra of new compounds in dilute THF
solutions (10-5 mol L-1) at room temperature.
vibronic feature. The PL behaviors of these compounds show
a red shift in comparison to their corresponding absorption. The
emission behavior of compound 3 peaked at 393 nm with a
vibronic emission at 417 nm. We also observed the maximum
emissions at 386 nm for compound 7, at 412 nm for compound
10, at 406 nm for compound 16, and at 397 nm for compound
19. From the PL feature of compound 13, both peaks at 383
and 403 nm showed almost the same emission intensity.
TABLE 1. Photophysical Properties of New Compounds in Dilute
THF Solutions (10-5 mol L-1
)
absorption
ꢀ
emission
compound
λ
max (nm)
(×105 M-1 cm-1
)
λ
max (nm)
3
302
369
341
303
341
297
357
388
312
313
363
380
0.90
1.2
0.73
0.93
0.70
1.1
0.70
0.50
0.97
0.77
1.4
393
417
386
412
7
10
13
383
403
Conclusion
In conclusion, we have successfully developed a highly
effective, regioselective oxidative cyclization method to con-
struct a series of polycyclic aromatic hydrocarbons containing
a 10H-indeno[1,2-b]triphenylene skeleton. The synthesis de-
scribed herein is generally accomplished in four steps: Sono-
gashira coupling, Diels-Alder reaction, decarbonylation, and
finally the FeCl3 oxidative cyclization. Compared with the
work,3,4 the replacement of 2,3,4,5-tetraphenylcyclopentadienone
with 2,5-diethyl-3,4-diphenylcyclopentadienone not only ef-
ficiently enhances the solubility of the desired polycyclic
aromatics but also provides an alternative synthetic route to
prepare PAH derivatives with interesting structures. Moreover,
we do not observe any C-C bond formation arising from
coupling of a pair of benzene rings in which both are not parts
of the fluorene unit. The utilization of this chemistry to construct
larger PAHs indicates that the scope of such oxidative cycliza-
tion by FeCl3 could be extended beyond simple fluorene
derivatives. The ease of synthesizing these large polycyclic
aromatics with interesting structures and their aromatic precur-
sors with the current method has allowed us to expand the pool
of cyclization strategies and to better understand the structure-
property relationship within such structures. The investigation
of photophysical properties also demonstrates the increase of
effective conjugated length after cyclization. These results
indicate that the derivatives of 13 and 16 might be suitable for
organic field effect transistor (OFET) applications. Detailed
studies on the photophysical properties of these new polycyclic
aromatics and their applications in optoelectronic devices are
currently underway in our laboratory.
16
19
406
397
1.5
pounds. Compounds 3, 10, and 13 exhibited similar absorption
peaks in this region (302 nm for 3, 303 nm for 10, and 297 nm
for 13), while compounds 16 and 19 showed the similar
absorption feature (312 nm for 16 and 313 nm for 19). The
molar extinction coefficients (ꢀ) of these peaks for these five
compounds were around ∼105 M-1 cm-1
.
Normally, oligofluorene and polyfluorene derivatives show
strong π-π* electron absorption bands in the visible region,
which is progressively red-shifted with increasing chain length.
For compound 3, the maximum absorption peaked, λmax, at 369
nm with a shoulder at 387 nm. For compound 7, its absorption,
λmax, was at 341 nm, which was close to that of the correspond-
ing oligofluorene derivatives.11 In comparison with compound
7 (λmax ) 341 nm), compound 3 exhibited the obvious red shift,
which might be due to the increasing effective conjugation
length by the 10H-indeno[1,2-b]triphenylene units. Similar
behaviors were also observed from the absorption spectra of
compounds 10 and 13. In comparison with compound 16,
compound 19 exhibited a broad absorption spectrum. Moreover,
its onset red-shifted from about 370 nm for compound 16 to
410 nm. These observations suggested the formation of a highly
extended π-delocalized system in compound 19.
Figure 2 illustrates the photoluminescent (PL) spectra for
these compounds in dilute THF solutions, and all compounds
showed similar behaviors and a maximum with a well-defined
Experimental Section
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M. J. Org. Chem. 2005, 70, 5309-5312. (b) Bacher, A.; Erdelen, C. H.;
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J. Am. Chem. Soc. 2001, 123, 11298-11299.
The ethynylene derivatives 1, 5, 8, 11, 14, and 17 have been
prepared by the literature procedures.4i,7
Compound 2. A dry flask with a magnetic stirrer was loaded
with 1 (0.42 g, 0.97 mmol), commercially available 2,5-diethyl-
3,4-diphenylcyclopentadienone (0.56 g, 1.93 mmol), and mesitylene
(11) Zhou, X.-H.; Yan, J.-C.; Pei, J. Org. Lett. 2003, 5, 3543-3546.
6826 J. Org. Chem., Vol. 71, No. 18, 2006

Construction of 10H-Indeno[1,2-b]triphenylene Skeletons
(15 mL). The mixture was refluxed for 24 h. After the evaporation
of the solvent under vacuum, the residue was purified by column
chromatography (petroleum ether/dichloromethane ) 15:1) to give
phenyl-9H-fluorene (0.76 g, 1.4 mmol) and 2,5-diethyl-3,4-diphe-
nylcyclopentadienone (0.80 g, 2.8 mmol) in mesitylene (15 mL)
gave 0.90 g (80%) of 9 as a white solid after purification by column
chromatography (petroleum ether/dichloromethane ) 15:1). 1H
NMR (CDCl3, 200 MHz, ppm): δ 7.65-7.69 (2H, d, J ) 8.0 Hz),
7.43-7.56 (5H, m), 7.35-7.39 (1H, d, J ) 8.0 Hz), 7.00-7.25
(15H, m), 6.65-6.69 (1H, dd, J ) 2.4 Hz, 8.6 Hz), 6.55-6.59
(1H, dd, J ) 2.4 Hz, 8.6 Hz), 3.64 (3H, s), 2.24-2.28 (4H, m),
1.86-1.95 (4H, m), 0.52-1.07 (28H, m). 13C NMR (CDCl3, 50
MHz, ppm): δ 157.5, 151.4, 149.87, 141.83, 141.80, 141.21,
141.17, 140.9, 140.6, 140.3, 139.7, 138.3, 138.1, 137.6, 133.4,
131.5, 131.4, 130.57, 130.50, 129.0, 128.8, 127.3, 127.2, 127.1,
127.05, 125.8, 125.1, 121.3, 119.7, 118.7, 112.7, 112.3, 54.9, 54.7,
40.6, 31.5, 29.9, 29.6, 24.5, 23.6, 23.4, 22.8, 22.4, 15.2, 15.1, 14.0,
13.9. MS (EI, m/z): 800 (M+, 100%), 715 (M+ - 85). Anal. Calcd
for C60H64O: C, 89.95; H, 8.05. Found: C, 89.55; H, 8.23.
Compound 10. This compound was prepared following proce-
dures similar to those used to prepare compound 3. Thus, the
reaction between 9 in 100 mL of dry dichloromethane (0.14 g, 0.17
mmol) and FeCl3 (0.28 g 1.7 mmol) in 5 mL of CH3NO2 gave
0.041 g (30%) of 10 as a white solid after product purification by
column chromatography (petroleum ether/dichloromethane ) 8:1).
1H NMR (CDCl3, 200 MHz, ppm): δ 8.78 (1H, s), 8.37-8.41 (1H,
d, J ) 9.2 Hz), 8.36 (1H, s), 8.11-8.13 (1H, d, J ) 2.4 Hz), 8.02-
8.06 (1H, d, J ) 8.0 Hz), 7.44-7.77 (8H, m), 7.11-7.24 (10H,
m), 4.10 (3H, s), 3.19-3.25 (4H, q, J ) 5.5 Hz), 2.08-2.16 (4H,
m), 0.70-1.28 (28H, m). 13C NMR (CDCl3, 50 MHz, ppm): δ
158.3, 152.1, 149.1, 141.7, 141.31, 141.29, 141.24, 140.7, 140.6,
140.2, 139.7, 135.1, 134.3, 132.8, 132.7, 132.3, 131.1, 131.0, 130.0,
128.9, 127.3, 127.1, 126.3, 125.9, 125.4, 122.7, 121.7, 120.3, 114.0,
113.7, 106.7, 55.5, 55.3, 40.9, 31.4, 29.7, 27.0, 26.8, 23.9, 22.5,
15.4, 15.1, 13.9. MS (EI, m/z): 798 (M+, 100%), 713 (M+ - 85).
Anal. Calcd for C60H62O: C, 90.18; H, 7.82. Found: C, 90.00; H,
7.92.
Compound 12. This compound was prepared following proce-
dures similar to those used to prepare compound 2. Thus, the
reaction between 9,9-dihexyl-2,7-bis(2-phenylethynyl)fluorene (0.54
g, 1.0 mmol) and 2,5-diethyl-3,4-diphenylcyclopentadienone (1.2
g, 4.0 mmol) in mesitylene (10 mL) gave 0.72 g (68%) of 12 as a
white solid after product purification by column chromatography
(petroleum ether/dichloromethane ) 10:1). 1H NMR (CDCl3, 200
MHz, ppm): δ 7.34-7.38 (2H, d, J ) 8.0 Hz), 7.01-7.10 (34H,
m), 2.20-2.28 (8H, m), 1.74-1.78 (4H, m), 0.57-1.00 (34H, m).
13C NMR (CDCl3, 50 MHz, ppm): δ 149.43, 149.40, 141.4, 141.3,
141.10, 141.03, 140.88, 140.85, 140.78, 139.6, 138.7, 137.7, 137.6,
137.5, 130.5, 128.7, 127.1, 125.7, 124.8, 118.3, 54.6, 41.1, 31.9,
31.7, 31.6, 30.0, 24.5, 23.3, 22.8, 22.4, 15.3, 15.2, 14.3, 14.1, 13.9.
MALDI-TOF MS, m/z: 1055 (M+). Anal. Calcd for C81H82: C,
92.17; H, 7.83. Found: C, 91.90; H, 7.82.
1
0.64 g (95%) of 2. H NMR (CDCl3, 300 MHz, ppm): δ 7.61-
7.63 (1H, m), 7.49-7.51 (1H, d, J ) 7.8 Hz), 7.19-7.30 (4H, m),
7.01-7.19 (16H, m), 2.32-2.37 (4H, m), 1.85-1.97 (4H, m),
0.54-1.26 (28H, m). 13C NMR (CDCl3, 75 MHz, ppm): δ 150.7,
149.5, 141.4, 141.21, 141.18, 141.0, 140.94, 140.91, 140.0, 138.8,
137.7, 137.6, 130.6, 130.54, 130.50, 130.4, 129.0, 127.1, 127.0,
126.94, 126.88, 126.54, 126.48, 125.73, 125.67, 125.2, 122.6, 119.4,
118.3, 54.8, 40.7, 40.6, 31.55, 31.48, 29.9, 29.6, 24.5, 23.7, 23.4,
22.7, 22.4, 15.23, 15.1, 13.9, 13.7. MS (EI, m/z): 694 (M+, 100%),
609 (M+ - 85). Anal. Calcd for C53H58: C, 91.59; H, 8.41. Found:
C, 91.19; H, 8.57.
Compound 3. Compound 2 (0.14 g, 0.20 mmol) was dissolved
in 100 mL of dry dichloromethane in a dry flask. A constant stream
of nitrogen was bubbled into the solution through a glass capillary.
A solution of FeCl3 (0.39 g, 2.4 mmol) in 5 mL of CH3NO2 was
then added dropwise via syringe at 0 °C. The reaction mixture was
stirred for 10 min and quenched by adding 50 mL of methanol.
The reaction mixture was added to 100 mL of water and extracted
with dichloromethane. After the evaporation of the solvents, the
residue was purified by column chromatography (petroleum ether/
dichloromethane ) 10:1) to give 0.10 g (73%) of 3 as a light yellow
1
solid. H NMR (CDCl3, 200 MHz, ppm): δ 8.87 (2H, s), 8.68-
8.72 (2H, d, J ) 8.0 Hz), 8.42-8.45 (2H, d, J ) 8.0 Hz), 8.36
(2H, s), 8.04-8.08 (2H, d, J ) 8.0 Hz), 7.54-7.81 (8H, m), 7.10-
7.26 (20H, m), 3.20-3.27 (8H, m,), 2.14-2.17 (8H, m), 0.70-
1.37 (56H, m). 13C NMR (CDCl3, 50 MHz, ppm): δ 152.2, 149.1,
141.5, 141.4, 141.2, 141.16, 141.0, 140.3, 139.8, 135.2, 135.1,
133.4, 132.7, 131.4, 131.2, 131.1, 131.0, 130.6, 130.3, 128.6, 127.2,
126.6, 126.4, 125.9, 123.7, 122.7, 121.7, 120.4, 114.0, 55.3, 40.9,
31.4, 29.7, 27.0, 26.8, 23.9, 22.5, 15.4, 15.3, 13.9. MALDI-TOF
MS, m/z: 1383 (M+). Anal. Calcd for C106H110: C, 91.99; H, 8.01.
Found: C, 91.61; H, 7.95.
Compound 6. Compound 6 was prepared by a procedure similar
to that used to prepare 2. Thus, the reaction between 9′,9′-dihexyl-
2′-fluorenylacetylene (0.50 g, 1.4 mmol) and 2,5-diethyl-3,4-
diphenylcyclopentadienone (0.80 g, 2.8 mmol) in mesitylene (15
mL) gave 0.63 g (73%) of 6 as a white solid after purification by
column chromatography (petroleum ether/dichloromethane ) 15:
1). 1H NMR (CDCl3, 200 MHz, ppm): δ 7.72-7.79 (2H, m), 7.33-
7.44 (6H, m), 7.01-7.12 (10H, m), 2.40-2.50 (4H, m), 1.95-
1.99 (4H, m), 0.65-1.13 (28H, m). 13C NMR (CDCl3, 75 MHz,
ppm): δ 150.8, 150.3, 141.9, 141.7, 141.3, 141.0, 140.9, 140.5,
139.7, 139.1, 137.3, 130.4, 130.2, 129.2, 127.9, 127.2, 127.1, 126.9,
126.7, 125.8, 124.0, 122.7, 119.6, 119.2, 55.1, 40.6, 31.5, 29.7,
26.7, 23.7, 23.6, 22.5, 15.5, 15.2, 13.2. MS (EI, m/z): 618 (M+,
100%), 533 (M+- 85). Anal. Calcd for C47H54: C, 91.21; H, 8.79.
Found: C, 91.01; H, 8.97.
Compound 7. This compound was prepared following a
procedure similar to that used to prepare compound 3. Thus, the
reaction between 6 (0.12 g, 0.20 mmol) in dry dichloromethane
(100 mL) and FeCl3 (0.39 g, 2.4 mmol) in 5 mL of CH3NO2 gave
0.060 g (50%) of 7 as a white solid after product purification by
column chromatography (petroleum ether/dichloromethane ) 10:
1). 1H NMR (CDCl3, 200 MHz, ppm): δ 7.80-7.86 (2H, dd, J )
8.0 Hz, 3.6 Hz), 7.67-7.72 (2H, m), 7.43-7.49 (2H, dd, J ) 8.0
Hz, 3.6 Hz), 7.29 (1H, s), 7.02-7.26 (10H, m), 2.44-2.50 (4H,
m), 2.07-2.10 (4H, m), 0.69-1.26 (28H, m). 13C NMR (CDCl3,
50 MHz, ppm): δ 151.6, 150.7, 141.9, 141.7, 141.5, 141.4, 140.9,
140.54, 140.52, 140.4, 140.2, 139.4, 139.1, 137.3, 130.4, 130.2,
129.2, 128.0, 127.2, 127.1, 126.1, 125.8, 124.1, 121.3, 119.8, 119.2,
55.2, 40.5, 31.5, 29.7, 26.7, 23.8, 23.7, 22.50, 22.47, 15.4, 15.2,
14.0, 13.9. MALDI-TOF MS, m/z: 1235 (M+). Anal. Calcd for
C94H106: C, 91.35; H, 8.65. Found: C, 91.09; H, 8.71.
Compound 13. This compound was prepared following a
procedure similar to that used to prepare compound 3. Thus, the
reaction between 12 (0.11 g, 0.10 mmol) in 100 mL of dry
dichloromethane and FeCl3 (0.26 g, 1.6 mmol) in 5 mL of CH3-
NO2 gave 0.10 g (95%) of 13 as a white solid after purification by
column chromatography (petroleum ether/dichloromethane ) 10:
1). 1H NMR (CDCl3, 200 MHz, ppm): δ 9.07 (2H, s), 8.80-8.82
(2H, d, J ) 7.2 Hz), 8.44-8.46 (2H, d, J ) 7.2 Hz), 8.37 (2H, s),
7.67-7.72 (2H, t, J ) 7.2 Hz), 7.50-7.60 (2H, t, J ) 7.2 Hz),
7.11-7.21 (20H, m), 3.20-3.28 (8H, m), 2.12-2.17 (4H, m),
0.82-1.06 (28H, m), 0.64-0.39 (6H, t, m). 13C NMR (CDCl3, 75
MHz, ppm): δ 149.2, 141.4, 141.3, 141.1, 141.0, 139.8, 135.12,
135.07, 133.3, 132.7, 131.3, 131.2, 131.02, 130.95, 130.3, 128.5,
127.1, 126.6, 125.9, 123.7, 122.7, 114.3, 55.4, 41.5, 31.5, 29.8,
29.7, 27.0, 26.9, 24.1, 22.5, 15.5, 15.3, 13.9. MALDI-TOF MS,
m/z: 1051 (M+). Anal. Calcd for C81H78: C, 92.52; H, 7.48.
Found: C, 92.12; H, 7.60.
Compound 9. This compound was prepared following proce-
dures similar to those used to prepare compound 2. Thus, the
reaction between 9,9-dihexyl-2-(2-(4-methoxylphenyl)ethynyl)-7-
Compound 15. This compound was prepared following proce-
dures similar to those used to prepare compound 2. Thus, the
reaction between 1,2-bis(9′,9′-dihexylfluoren-2′-yl)ethyne (0.80 g,
J. Org. Chem, Vol. 71, No. 18, 2006 6827

Zhou et al.
1.2 mmol), 2,5-diethyl-3,4-diphenylcyclopentadienone (0.69 g, 2.4
mmol), and mesitylene (15 mL) gave 1.0 g (91%) of 15 as a white
solid after product purification by column chromatography (petro-
leum ether/dichloromethane ) 20:1). 1H NMR (CDCl3, 200 MHz,
ppm): δ 7.48-7.51 (2H, m), 7.39-7.43 (2H, d, J ) 8.0 Hz), 6.99-
7.23 (20H, m), 2.28-2.36 (4H, m), 1.79-1.86 (8H, m), 0.25-
1.11 (50H, m). 13C NMR (CDCl3, 50 MHz, ppm): δ 150.5, 149.6,
141.4, 141.1, 141.0, 140.9, 140.0, 138.7, 137.7, 130.6, 130.4, 129.7,
128.7, 127.1, 126.6, 126.5, 125.7, 125.2, 123.2, 122.4, 119.4, 118.9,
118.3, 54.8, 40.7, 31.6, 31.5, 30.0, 29.7, 24.5, 23.6, 23.4, 22.8, 22.5,
15.2, 14.0, 13.9. MALDI-TOF MS, m/z: 951 (M+). Anal. Calcd
for C72H86: C, 90.89; H, 9.11. Found: C, 90.77; H, 9.07.
MHz, ppm): δ 150.5, 149.48, 149.43, 141.43, 141.35, 141.12,
141.07, 140.8, 140.0, 139.5, 138.8, 138.6, 137.8, 137.6, 130.6,
130.4, 128.7, 128.5, 127.0, 126.5, 126.5, 125.7, 125.2, 124.8, 124.4,
119.4, 118.3, 54.8, 54.6, 41.1, 40.8, 40.6, 31.7, 31.6, 31.2, 30.1,
29.7, 24.5, 23.6, 23.3, 22.8, 22.7, 22.5, 15.2, 14.01, 13.98, 13.92.
MALDI-TOF MS, m/z: 1567 (M+). Anal. Calcd for C119H138: C,
91.13; H, 8.87. Found: C, 91.01; H, 8.91.
Compound 19. This compound was prepared following a
procedure similar to that used to prepare compound 3. Thus, the
reaction between 18 (0.18 g, 0.11 mmol) in 100 mL of dry
dichloromethane and FeCl3 (0.43 g, 2.6 mmol) in 10 mL of CH3-
NO2 gave 0.11 g (61%) of 19 as a white solid after product
purification by column chromatography (petroleum ether/dichlo-
Compound 16. This compound was prepared following a
procedure similar to that used to prepare compound 3. Thus, the
reaction between 15 (95 mg, 0.10 mmol) in 50 mL of dry
dichloromethane and FeCl3 (0.19 g 1.2 mmol) in 5 mL of CH3-
NO2 gave 0.089 g (94%) of 16 as a white solid after product
purification by column chromatography (petroleum ether/dichlo-
1
romethane ) 10:1). H NMR (CDCl3, 300 MHz, ppm): δ 9.19
(2H, s), 9.10 (2H, s), 8.37 (2H, s), 8.34 (2H, s), 8.21-8.24 (2H, d,
J ) 7.5 Hz), 7.52-7.56 (2H, m), 7.40-7.42 (4H, m), 7.07-7.20
(20H, m), 3.22-3.24 (8H, m), 2.04-2.09 (12H, m), 1.03-1.17
(48H, m), 0.47-0.94 (30H, m). 13C NMR (CDCl3, 75 MHz, ppm):
δ 151.4, 149.1, 148.6, 141.25, 141.18, 141.17, 141.14, 140.2, 140.0,
134.90, 134.89, 133.5, 133.4, 131.0, 130.9, 130.8, 130.60, 130.59,
127.5, 127.14, 127.07, 125.9, 123.1, 122.7, 122.6, 120.4, 114.5,
114.3, 55.3, 55.2, 41.5, 41.0, 31.51, 31.47, 29.82, 29.80, 29.71,
29.67, 27.2, 24.1, 23.9, 22.6, 22.5, 15.4, 14.0, 13.9. MALDI-TOF
MS, m/z: 1563 (M+). Anal. Calcd for C119H134: C, 91.37; H, 8.63.
Found: C, 91.07; H, 8.58.
1
romethane ) 10:1). H NMR (CDCl3, 300 MHz, ppm): δ 8.92
(2H, s), 8.31 (2H, s), 8.01-8.03 (2H, d, J ) 7.2 Hz), 7.35-7.43
(6H, m), 7.02-7.18 (10H, m), 3.19-3.21 (4H, m), 2.05-2.11 (8H,
m), 1.05-1.12 (30H, m), 0.67-0.80 (20H, m). 13C NMR (CDCl3,
75 MHz, ppm): δ 151.3, 148.4, 141.15, 141.11, 141.0, 140.1, 134.8,
133.4, 131.0, 130.5, 130.4, 127.4, 127.1, 126.9, 125.8, 123.0, 122.5,
120.1, 113.9, 55.2, 40.9, 31.5, 29.8, 27.2, 23.9, 22.5, 15.4, 14.0.
MALDI-TOF MS, m/z: 949 (M+). Anal. Calcd for C72H84: C,
91.08; H, 8.92. Found: C, 90.87; H, 9.00.
Acknowledgment. This work was supported by the Major
State Basic Research Development Program (No. 2002CB613402)
from the Ministry of Science and Technology, China, and
National Natural Science Foundation of China (NSFC 20425207,
50473016, 20521202, and 20544004).
Compound 18. This compound was prepared following proce-
dures similar to those used to prepare compound 2. Thus, the
reaction between 9,9-dihexyl-2,7-bis(2-(9′′,9′′-dihexylfluoren-2′′-
yl)ethynyl)fluorene (0.21 g, 0.2 mmol), 2,5-diethyl-3,4-diphenyl-
cyclopentadienone (0.23 g, 0.8 mmol), and mesitylene (5 mL) gave
0.24 g (76%) of 18 as a white solid after purification by column
chromatography (petroleum ether/dichloromethane ) 15:1). 1H
NMR (CDCl3, 200 MHz, ppm): δ 7.43-7.46 (2H, m), 7.32-7.36
(2H, d, J ) 7.8 Hz), 6.97-7.18 (36H, m), 2.22-2.29 (8H, m),
1.80-1.90 (12H, m), 0.17-1.09 (78H, m). 13C NMR (CDCl3, 75
Supporting Information Available: 1H and 13C NMR, MS
spectra for all new compounds. This material is available free of
charge via the Internet at http://pubs.acs.org.
JO0609172
6828 J. Org. Chem., Vol. 71, No. 18, 2006