Synthesis and mesomorphic property of novel discotic C60- triphenylene derivative

Article abstract of DOI:10.2174/157017811797249434

By reacting monohydroxytriphenylene 2 with 1,6-dibromohexane and then condensating with 4-hydroxybenzaldehyde, triphenylene derivative with mono-aldehyde group 4 was prepared in ideal yield. Further treating compound 4 with C₆₀ and sarcosine, the novel discotic C₆₀- triphenylene derivative 5 was prepared by 1,3-dipolar cycloaddition in a yield of 35%. DSC analysis and observation with polarized optical microscopy indicated that compound 5 possessed mesomorphic property.

Full text of DOI:10.2174/157017811797249434

Letters in Organic Chemistry, 2011, 8, 599-602
599
Synthesis and Mesomorphic Property of Novel Discotic C -Triphenylene
6
0
Derivative
,1,2
1
1
1
1
Fafu Yang* , Hongyu Guo , Jianwei Xie , Zhiqiang Liu and Bingting Xu
1
College of Chemistry and Materials Science, Fujian Normal University, Fuzhou 350007, P.R. China
2
Fujian Key Laboratory of Polymer Materials, Fuzhou 350007, P.R. China
Received April 10, 2011: Revised May 10, 2011: Accepted June 20, 2011
Abstract: By reacting monohydroxytriphenylene 2 with 1,6-dibromohexane and then condensating with 4-
hydroxybenzaldehyde, triphenylene derivative with mono-aldehyde group 4 was prepared in ideal yield. Further treating
compound 4 with C60 and sarcosine, the novel discotic C60-triphenylene derivative 5 was prepared by 1,3-dipolar cycload-
dition in a yield of 35%. DSC analysis and observation with polarized optical microscopy indicated that compound 5 pos-
sessed mesomorphic property.
Keywords: 1,3-dipolar cycloaddition, fullerene, liquid crystal, synthesis, triphenylene.
Fullerene has received considerable attention and much
research interest due to its unique structure and interesting
properties [1-3]. Many functional groups have been intro-
duced, often region- or stereoselectively, for tuning of the
physical properties of C60 and for construction of su-
pramolecular architectures [4-6]. Among all kinds of C60
derivatives, the discotic molecule-substituted C60 derivatives
showed interesting properties, especially, liquid crystal prop-
erties. Up to now, few C60 derivatives with discotic-
molecular groups and their liquid crystal properties were
studied. In 1998, Deschenaux reported the first mesomorphic
cleavage with B-bromocatechol-boronane following litera-
ture method [13]. Reacting compound 2 with excess 1, 6-
dibromohexane under K CO /MeCN system afforded ꢀ-
bromo-substituted triphenylene 3 in 70% yield after column
chromatography. Subsequently, the triphenylene derivative 4
with terminal aldehyde group was prepared in 75% yield by
condensating compound 3 with 4-hydroxybenzaldehyde in
2
3
2 3
K CO /MeCN system after column chromatography. Further,
by treating compound 4 with sarcosine and C60 in refluxing
toluene, the novel discotic C60-triphenylene derivative 5 was
obtained in 35% isolated yield via 1,3-dipolar cycloaddition
of azomethine ylides to C60 after column chromatography.
Although the muti-step synthetic procedures and purification
with column chromatography, novel discotic C60-triphen-
ylene derivative 5 was still obtained in reasonable yield. To
the best of our knowledge, compound 5 was the first exam-
ple of discotic C60-triphenylene derivative 5 obtained by 1,3-
dipolar cycloaddition, although other two C60-triphenylene
derivatives were synthesized by Bingel-type reaction [11, 12].
C60-ferrocene derivative [7]. Tian synthesized a C60-perylene
derivative in 2004 [8]. Nakanishi prepared a series of un-
common liquid C60 derivatives with 2,4,6-tris(alkyloxy) ben-
zal groups in 2006 [9]. Lately, Geerts described the synthesis
of mesogenic phthalocyanine-C60 [10]. Triphenylene was one
of the most important discotic molecules with exciting
mesomorphic properties. However, due to the difficult muti-
step synthetic procedures, only two C60-triphenylene deriva-
tives were obtained by Bingel-type reaction with outstanding
liquid crystal properties of self-assembled columns [11, 12].
Besides these two researches, the studies on the synthesis
and properties of other C60-triphenylene derivatives are un-
known so far. In this paper, we wish to report the design and
synthesis of a new kind of C60-triphenylene derivative by 1,
The structures of new compounds 3, 4 and 5 were charac-
1
terized by element analyses, UV, IR, ESI-MS, H NMR and
1
3
C NMR spectra. The UV spectrum of compound 5 was
showed in Fig. (1). It could be seen the typical absorption
features of mono-fulleropyrrolidine at 256, 309 and 432 nm.
The ESI-MS spectrum of compound 5 showed correspond-
1
3
-dipolar cycloaddition of the azomethine ylide generated in
ing molecular ion peak at 1626.48. The H NMR spectrum of
situ from aldehyde and sarcosine.
compound 5 was showed in Fig. (2) and all the protons in
compound 5 were assigned well. Especially, the typical split
1
, 3-dipolar cycloaddition was a typical reaction for pre-
of NCH (a and a’) on pyrrole ring and ArH (c and d) were
2
paring C60 derivatives [5], however, this reaction was not
applied to preparing C60-triphenylene derivative so far. Thus,
we designed a synthetic route using this reaction to prepare
novel C60-triphenylene 5 as demonstrated in Scheme 1. The
monohydroxytriphenylene 2 was prepared by oxidation of 1,
13
observed clearly. Although the C NMR spectrum of com-
pound 5 showed complicated peaks in 133~148 ppm due to
the overlapped signals of carbon on the skeleton of triphen-
ylene and C60, the peaks of NCH
2
at 68.04 ppm and 69.05
ppm, NCH at 40.08, NCH at 83.27 ppm certainly supported
3
2
3
-dipentyloxylbenzene with FeCl and then selective ether
the structure of compound 5. All these typical characteriza-
tion of spectrum were similar to structures of mono-
fulleropyrrolidine in literatures [4, 6, 12, 13].
*
Address correspondence to this author at the College of Chemistry and
Materials Science, Fujian Normal University, Fuzhou 350007, P. R. China;
Tel: 0086-591-83465225; Fax: 0086-591-83465225;
E-mail: yangfafu@fjnu.edu.cn
The mesomorphic behavior of compound 5 was prelimi-
narily studied by DSC and the phase texture was investigated
1
570-1786/11 $58.00+.00
© 2011 Bentham Science Publishers

6
00 Letters in Organic Chemistry, 2011, Vol. 8, No. 8
Yang et al.
RO
OR
RO
OR
RO
OR
O
O
FeCl
CH Cl
RO
3
B
Br
2 6
Br-(CH ) -Br
2
2
RO
OR
2 2
CH Cl
K CO , MeCN
2
3
OR
RO
OH
RO
2 6
O (CH ) -Br
RO
OR
RO
OR
RO
OR
1
3
2
n-C
5
H
11
O
OC
5
H11-n
K
2
CO
3
,
HO
CHO
RO
OR
O
N
H
N
n-C
5
H
11
O
O
2 6
(CH ) -O
C
60,
OH
n-C
5
H
11
O
OC
5
H11-n
Toluene, refluxing
RO
O
(CH
2
)
6
-O
CHO
5
RO
OR
R= -C
4
5
H11-n
Scheme 1. The synthetic route of triphenylene-C60 derivative 5.
under polarized optical microscopy. Results showed that
MHz, CDCl
1.42~1.98 (m, 38H, CH
4.23 (t, 12 H, J = 6.6Hz, OCH
(%): 836.24 (M , 100). Anal. calcd for C49
H 8.78; found C 70.15, H 8.84.
3
) ꢀppm: 0.98 (t, 15H, J = 6.6Hz, CH
3
2
),
),
compound 5 possessed mesomorphic property, which was
2
), 3.46 (t, 2H, J = 6.0Hz, BrCH
o
confirmed by the two endothermic peaks at 76.6 C and
2
), 7.84 (s, 6H, ArH); MS m/z
o
+
9
0.6 C in the DSC measurement and the mesomorphic tex-
73 6
H O Br: C 70.22,
o
ture under POM at 85 C as showed in Fig. (3). The in-depth
studies on liquid crystal properties and electrochemistry
property based on the large conjugation action between
triphenylene unit and C60 unit, will be investigated in the
following work.
The Procedure for Synthesis of Compound 4
Compound (0.84 g, mmol) and 4-
hydroxybenzaldehyde (0.31 g, 2.5 mmol) with K CO (0.35
g, 2.5 mmol) were refluxed in 50 mL MeCN overnight and
purged with N . After reaction, the mixture was filtered and
evaporated to dryness by rotavapor. Then the mixture was
further purified by column chromatography (SiO 100-200
mesh, petroleum ether / CH Cl (5:1, V/V) as eluant). The
compound 4 was obtained as grayish solid in yield of 75%.
3
1
2
3
2
2
2
2
1
Compound 4: H NMR (600 MHz, CDCl
3
) ꢀppm: 0.98 (t,
), 1.44~1.96 (m, 38H, CH ), 4.07 (t, 2H,
), 6.98 (d, 2H, J =
1
5H, J = 6.6Hz, CH
J = 6.0Hz, OCH
3
2
2
) , 4.24 (m, 12 H, OCH
2
8
.4Hz, ArH), 7.81 (d, 2H, J = 8.4Hz, ArH), 7.84 (s, 6H,
+
ArH), 9.87 (s, 1H, ArCHO); MS m/z (%): 878.68 (M , 100).
Anal. calcd for C56 : C 76.50, H 8.94; found C 76.44, H
.89.
78 8
H O
8
The Procedure for Synthesis of Compound 5
Fig. (1). UV-vis absorption spectrum of novel discotic C60
triphenylene derivative 5.
-
A mixture of compound 4 (0.44g, 0.5 mmol), C60 (0.36 g,
0
.5 mmol), and sarcosine (0.45g, 5 mmol) in dry toluene
(
200 mL) was refluxed for 48 h. After the reaction mixture
The Procedure for Synthesis of Compound 3
was cooled to room temperature, the solvent was removed
under reduced pressure and the residue was further purified
Compound 2 (1.35 g, 2 mmol) and 1,6-dibromohexane
1.22 g, 5 mmol) with K CO (0.97g, 7 mmol) were refluxed
in 50 mL acetonitrile overnight and purged with N . After
by column chromatography (SiO
ether / CH Cl (1:1, V/V) as eluant). Compound 5 was ob-
tained as brown solid in yield of 35%. Compound 5: H
NMR (600 MHz, CDCl ) ꢀppm: 0.96 (t, 15H, J = 6.0Hz,
CH ), 1.45~1.96 (m, 38H, CH ), 2.77 (s, 3H, NCH ), 3.99 (t,
H, J = 6.6Hz, OCH ) , 4.22 (m, 13H, OCH and NCH ),
4.84 (s, 1H, ArCH), 4.95 (d, 1H, J = 9.6 Hz, NCH ), 6.94 (d,
H, J = 10.8Hz, ArH), 7.67 (br s, 2H, ArH), 7.82 (br s, 6H,
2
100-200 mesh, petroleum
(
2
3
2
2
2
1
reaction, the mixture was filtered and evaporated to dryness
by rota-vapor. Then the mixture was further purified by col-
3
3
2
3
umn chromatography (SiO
CH Cl (10:1, V/V) as eluant). Compound 3 was obtained as
gray soft solid in yield of 70%. Compound 3: H NMR (600
2
100-200 mesh, petroleum ether /
2
2
2
2
2
2
1
2
2

Synthesis and Mesomorphic Property of Novel Discotic
Letters in Organic Chemistry, 2011, Vol. 8, No. 8
601
1
Fig. (2). H NMR spectrum of novel discotic C60-triphenylene derivative 5.
8
6
4
2
0
2
4
6
Cooling
-
-
-
Heating
40
60
80
100
120
o
Temperature
（
C）
o
-1
o
Fig. (3). DSC trace of 5 (scan rate 10 C min ) and texture of 5 under POM at 85 C (ꢁ200).
1
3
ArH); C NMR (150 MHz, CDCl
3
) ꢀppm: 14.42, 22.84,
REFERENCES
2
6
1
1
1
1
1
1
1
1
6.26, 26.32, 28.65, 29.38, 29.40, 29.61, 29.71, 40.08, 68.04,
[
1]
Sawamura, M.; Kawai, K.; Matsuo, Y.; Kanie, K.; Kato, T.; Naka-
mura, E. Stacking of Conical Molecules with Fullerene Apex into
Polar Columns in Crystals and Liquid Crystals. Nature, 2002, 419,
9.06, 69.81, 69.88, 69.94, 69.99, 70.05, 83.27, 107.66,
07.76, 123.93, 123.98, 124.03, 129.01, 135.87, 135.94,
36.65, 136.91, 139.67,139.97, 140.18, 141.64, 141.74,
41.91, 142.06, 142.08, 142.10, 142.19, 142.24, 142.33,
42.39, 142.62, 142.67, 142.75, 143.01, 143.10, 143.23,
44.46, 144.69, 144.78, 145.20, 145.29, 145.34, 145.39,
45.41, 145.48, 145.54, 145.56, 145.62, 145.87, 145.98,
46.00, 146.16, 146.20, 146.22, 146.27, 146.36, 146.38,
46.53, 146.56, 146.91, 147.35, 147.36, 149.25, 149.28. FT-
7
02-705.
[2]
Wang, S.; Jiang, H.; Lv, X.; Song, L.; Zhang, J. Progress in the
Synthesis of Heterocycle-Fused C(60)-fullerene Derivatives. Chin.
J. Org. Chem., 2006, 26, 168-180.
Nakanishi, T.; Miyashita, N.; Michinobu, T.; Wakayama, Y.; Tsu-
ruoka, T.; Ariga, K. D.; Kurth, G. Perfectly Straight Nanowires of
Fullerenes Bearing Long Alkyl-Chains on Graphite. J. Am. Chem.
Soc., 2006, 128, 6328-6329.
Zhang, P.; Guo, Z.; Lv, S. synthesis and aggregation properties of
amphiphilic mono and bisadducts of fullerene in aqueous solution.
Chin. Chem. Lett., 2008, 19, 1039-1042.
Hirsch, A.; Brettreich, M. Fullerenes: Chemistry and Reactions,
Wiley-VCH: Weinheim, Germany, 2005.
[3]
[4]
-
1
IR (KBr) v / cm : 2931, 2858, 1614, 1510, 1433, 1384,
+
1
261, 1170, 1036, 839, 767; MS m/z (%): 1626.48 (M , 20).
Anal. calcd for C118 N: C 87.11, H 5.14, N 0.86; found
C 87.03, H 5.10, N 0.79.
[
5]
6]
83 7
H O
[
Zhu, Y.; Zhou, S.; Cao, L.; Kan, Y. Advancements and Prospects
of [2＋2] Cycloaddition to [60]Fullerene. Chin. J. Org. Chem.,
2
007, 27, 313-321.
ACKNOWLEDGEMENTS
[
7]
Deschenaux, R.; Schweissguth, M.; Levelut, A. Electron-transfer
induced mesomorphism in the ferrocene–ferrocenium redox
system: first ferrocenium-containing thermotropic liquid crystal.
Chem. Commun., 1996: 1275-1276.
Hua, J.; Ding, F.; Meng, F.; Tian, H. Synthesis of a Novel Organic
Soluble and Thermal-stable Fullerene-perylene Dyad. Chin. Chem.
Lett., 2004, 15, 1373-1376.
Supported by the National Natural Science Foundation of
China (No. 20402002), Fujian Natural Science Foundation
of China (No. 2011J01031) and the Program for excellent
young researchers in the University of Fujian Province
[8]
(
JA10056), were greatly acknowledged.

6
02 Letters in Organic Chemistry, 2011, Vol. 8, No. 8
Yang et al.
[
[
9]
Michinobu, T.; Nakanishi, T.; Hill, J.; Funahashi, M.; Ariga, K.
Room Temperature Liquid Fullerenes: An Uncommon Morphology
of C60 Derivatives. J. Am. Chem. Soc., 2006, 128, 10384-10385.
Geerts, Y.; Debever, O.; Amato, C.; Sergeyev, S. Synthesis of
mesogenic phthalocyanine-C60 donor–acceptor dyads designed for
molecular heterojunction photovoltaic devices. Beilstein J. Org.
Chem., 2009, 5, No. 49.
Manickam, M.; Smith, A.; Belloni, M.; Shelley, E.; Ashton, P.;
Spencer, A.; Preece, J. Introduction of bis-discotic and bis-
calamitic mesogenic addends to C60. Liquid Crystals, 2002, 29,
497-504.
Bushby, R.; Hamley, I.; Liu, Q.; Lozman, O.; Lydon, J. Self-
assembled columns of fullerene. J. Mater. Chem. 2005, 15, 4429-
4434.
Kumar S., Manickam M. Synthesis of Functionalized Triphen-
ylenes by Selective Ether Cleavage with B-Bromocatecholborane.
Synthesis, 1998, 1119-1122.
[12]
[13]
10]
11]
[