One-pot facile synthesis of pyridyl annelated perylene bisimides

Article abstract of DOI:10.1021/ol902526t

(Figure presented) Two regiospecifically pyridyl annelated perylene bisimides have been prepared in one pot by the combination of the Suzuki cross-coupling reaction and subsequent light-promoted cyclization In high yields.

Full text of DOI:10.1021/ol902526t

ORGANIC
LETTERS
2010
Vol. 12, No. 2
228-231
One-Pot Facile Synthesis of Pyridyl
Annelated Perylene Bisimides
Wei Jiang,†,‡ Yan Li,†,‡ Wan Yue,†,‡ Yonggang Zhen,†,‡ Jianqiang Qu,§ and
Zhaohui Wang*,†
Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese
Academy of Sciences, Beijing 100190, China, Graduate School of the Chinese
Academy of Sciences, Beijing 100190, China, and Performance Chemicals Research,
BASF SE, Ludwigshafen 67056, Germany
wangzhaohui@iccas.ac.cn
Received November 2, 2009
ABSTRACT
Two regiospecifically pyridyl annelated perylene bisimides have been prepared in one pot by the combination of the Suzuki cross-coupling
reaction and subsequent light-promoted cyclization in high yields.
Perylene bisimides (PBIs) as chromophores are the subjects
of current research interest largely due to their exceptional
optical and electronic properties, photochemical stabilities,
high quantum yields, and ability to self-assemble into ordered
supramolecular structures.1 In particular, they have found
wide applications as electron transfer cascades,2 photovoltaic
devices,3 organic field effect transistors,4 liquid crystalline
materials,5 and NIR absorbing systems.6
ides (1) induces a significant bathochromic shift to the near-
infrared (NIR),6c and enlargement along the short axis such
as coronene derivatives (2) causes a hypsochromic shift,
leading to yellow chromophores with high stability,5a,7 or
results in almost full absorption in the visible region with
high extinction coefficient for the triply linked fully conju-
gated oligomeric perylene bisimides.8 Annelation of PBIs
with diverse heterocycles in bay-regions have also been
The extension of the aromatic core of perylene is a
currently active topic, the goal being to modulate their
structure and properties to improve their performance as
functional materials in devices. Arguably, extension along
the long molecular axis from perylene to hexarylene bisim-
(3) (a) Dittmer, J. J.; Marseglia, E. A.; Friend, R. H. AdV. Mater. 2000,
12, 1270. (b) Shin, W. S.; Jeong, H.; Kim, M.; Jin, S.; Kim, M.; Lee, J.;
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T. J.; Wasielewski, M. R. Angew. Chem., Int. Ed. 2004, 43, 6363. (b) Jones,
B. A.; Facchetti, A.; Wasielewski, M. R.; Marks, T. J. J. Am. Chem. Soc.
2007, 129, 15259.
† Institute of Chemistry, Chinese Academy of Sciences.
‡ Graduate School, Chinese Academy of Sciences.
(5) (a) Rohr, U.; Schlichting, P.; Bo¨hm, A.; Gross, M.; Meerholz, K.;
Bra¨uchle, C.; Mu¨llen, K. Angew. Chem., Int. Ed. 1998, 37, 1434. (b) Pisula,
W.; Kastler, M.; Wasserfallen, D.; Robertson, J. W. F.; Nolde, F.; Kohl,
C.; Mu¨llen, K. Angew. Chem., Int. Ed. 2006, 45, 819. (c) Wicklein, A.;
Lang, A.; Muth, M.; Thelakkat, M. J. Am. Chem. Soc. 2009, 131, 14442.
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Schryver, F. C.; Mu¨llen, K. Chem.sEur. J. 1997, 3, 219. (b) Kohl, C.;
Becker, S.; Mu¨llen, K. Chem. Commun. 2002, 23, 2778. (c) Pschirer, N. G.;
Kohl, C.; Nolde, F.; Qu, J.; Mu¨llen, K. Angew. Chem., Int. Ed. 2006, 45,
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§ Performance Chemicals Research, BASF SE.
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(b) Wu¨rthner, F. Chem. Commun. 2004, 14, 1564. (c) van der Boom, T.;
Hayer, R. T.; Zhao, Y.; Bushar, P. J.; Weiss, E. A.; Wasielewski, M. R.
J. Am. Chem. Soc. 2002, 124, 9582.
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Gaines, G. L.; Wasielewski, M. R. Science 1992, 257, 63. (b) Tauber, M. J.;
Kelley, R. F.; Giaimo, J. M.; Rybtchinski, B.; Wasielewski, M. R. J. Am.
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.
10.1021/ol902526t  2010 American Chemical Society
Published on Web 12/10/2009

investigated.9 Recently, we have developed a facile synthetic
methodology to produce bay-annelation of S-heterocyclic PBI
(3), which displays extraordinary supramolecular self-as-
sembly behavior by the inclusion of different guest mol-
ecules.10
Scheme 1
.
Synthesis of Regiospecifically Pyridyl Annelated
PBIs and Subsequent Quaternization
Figure 1. PBIs and core-extended PBIs.
Pyridine is one of the most widely used motifs for
providing versatile reactivity for the synthesis of biologically
active compounds and has been observed to act as a good
ligand that can afford diverse linking sites to transition metal
ions with tunable binding strength and directionality. In
recent years, pyridine complexes11 have also been used as
building blocks to form various supramolecular structures
such as macrocycles, nanotubes, and coordination polymers.
It is well-known that conventional imidization with pyridyl
amines,12 as well as the substitution with pyridin-ol or thiol
in the bay-regions13 of PBIs, has often been employed to
prepare PBI derivatives that bearing pyridine groups; how-
ever, transition-metal-catalyzed direct PBIs-pyridine cross-
coupling has not yet been reported.
Herein, we present the first example of a one-pot synthesis
of two regiospecifically pyridyl annelated PBIs in the bay-
regions by the combination of the Suzuki cross-coupling
reaction and subsequent light-promoted cyclization. Further-
(8) (a) Qian, H.; Wang, Z.; Yue, W.; Zhu, D. J. Am. Chem. Soc. 2007,
129, 10664. (b) Qian, H.; Negri, F.; Wang, C.; Wang, Z. J. Am. Chem.
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Lett. 2009, 11, 3084.
more, the ionic derivatives by quaternization have also been
synthesized, of which the optical properties are significantly
changed.
The synthesis of monobrominated PBIs and the separation
of dibrominated PBIs are always intriguing targets.14 We
have found the synthesis of monobromo- and dibromop-
erylene bisanhydride in one pot with 1.0 equiv of Br2 in a
shorter reaction time (see Supporting Information). After
imidization, the mixture was separated by column chroma-
tography to produce 1,7(6)-dibromo-PBI (first fraction, yield
(9) (a) Langhals, H.; Kirner, S. Eur. J. Org. Chem. 2000, 365. (b) Li,
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H.; Shirman, E.; Wolf, S. Angew. Chem., Int. Ed. 2009, 48, 926. (d) Zhang,
W.; Jin, W.; Fukushima, T.; Ishii, N.; Aida, T. Angew. Chem., Int. Ed.
2009, 48, 4747. (e) Geng, Y.; Wang, X.; Chen, B.; Xue, H.; Zhao, Y.; Lee,
S.; Tung, C.; Wu, L. Chem.sEur. J. 2009, 15, 5124.
(12) (a) Wu¨rthner, F.; Sautter, A.; Schmid, D.; Weber, P. J. A.
Chem.sEur. J. 2001, 7, 894. (b) You, C.; Wu¨rthner, F. J. Am. Chem. Soc.
2003, 125, 9716.
(14) For recent examples, see: (a) Bo¨hm, A.; Arms, H.; Henning, G.;
Blaschka, P. (BASF AG) German Pat. DE 19547209 Al, 1997; Chem. Abstr.
1997, 127, 96569g. (b) Wu¨rthner, F.; Stepanenko, V.; Chen, Z.; Saha-Mo¨ller,
C. R.; Kocher, N.; Stalke, D. J. Org. Chem. 2004, 69, 7933. (c) Fan, L.;
Xu, Y.; Tian, H. Tetrahedron Lett. 2005, 46, 4443. (d) Qiu, W.; Chen, S.;
Sun, X.; Liu, Y.; Zhu, D. Org. Lett. 2006, 8, 867. (e) Rajasingh, P.; Cohen,
R.; Shirman, E.; Shimon, L. J. W.; Rybtchinski, B. J. Org. Chem. 2007,
72, 5973.
(13) (a) Qu, J.; Kohl, C.; Pottek, M.; Mu¨llen, K. Angew. Chem., Int.
Ed. 2004, 43, 1528. (b) He, X.; Liu, H.; Li, Y.; Wang, S.; Li, Y.; Wang,
N.; Xiao, J.; Xu, X.; Zhu, D. AdV. Mater. 2005, 17, 2811. (c) Li, C.;
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Org. Lett., Vol. 12, No. 2, 2010
229

25%) and 1-bromo-PBI (second fraction, yield 37%). The
1,6-isomer could be removed by recrystallization from
toluene according to the literature15 to assign unequivocally
the regioisomerically pure 1,7-isomer (total yield 15%),
which is a prerequisite for the synthesis of pure disubstituted
perylene bisimides derivatives and further investigation of
their electro-optical properties.
Differring from π-π interaction, various noncovalent
intermolecular interactions such as ionic self-assembly from
oppositely charged systems are of paramount importance for
creating new columnar superstructures and allowing one to
tune liquid crystal (LC) properties.17 Accordingly, to prove
the reactivities of the pyridine units annelated on the highly
electron-deficient PBI core, quaternization is carried out by
treatment with an excess of methyl iodide in boiling
acetonitrile to afford the positively charged heterocyclic
annelated PBIs (6 and 9) readily.
All of the compounds are unambiguously characterized
by mass spectrometry, NMR spectroscopy, and elemental
analyses. Compound 5 is highly soluble in various organic
solvents, such as CH2Cl2, acetone, and toluene, except in
the case of the doubly cyclized product 8, which dissolved
reasonably only in CHCl3 and toluene. The positively charged
PBIs 6 and 9 only dissolve readily in CH3CN and DMSO.
Table 1. Photophysical Properties of the Heterocyclic Annelated
PBIs
a
b
c
Abs
[nm]
εa [M-1 cm-1
]
Fluormax [nm]
Φfl
max
5
6
8
9
498
498
486
485
71 500
23 300
46 200
18 600
509
514
495
494
1.00
0.59
0.80
0.02
a Measured in dilute THF solution (1.0 × 10-5 M). b Measured in dilute
THF solution (1.0 × 10-6 M). c In THF, PBI (N,N′-di(2,6-diisopropylphe-
nyl)perylene-3,4:9,10-tetracarboxylic acid bisimide, Φ fl ) 1.00 in CHCl3)
as the standard.
Room-temperature absorption and emission spectra of
these compounds are shown in Figure 2. The UV-vis
absorption spectra showed that they all exhibit well-defined
vibronic π-π* transition absorption bands with high extinc-
Figure 2. (a) UV-vis absorption and (b) fluorescence emission
spectra of 5 (black line), 6 (red line), 8 (blue line), and 9 (green
line) in THF at room temperature.
tion coefficients (εmax ) 71 500 M-1 cm-1 for 5, and εmax
)
46 200 M-1 cm-1 for 8). Compounds 5 and 8 are blue-shifted
relative to the corresponding parent compound (PBI)18 as a
reflection of the extended perylene core along the short
molecular axis. The spectra of 8 shows a sharp band with a
defined structure at 346 nm, whereas after quaternization,
the band with a maximum absorbance of 357 nm in the
spectra of 9 is broad. The longest absorbance maximum of
8 at 486 nm is slightly hypsochromically shifted compared
to dibenzocoronene bisimide (494 nm, εmax ) 66 000 M-1
cm-1 in CHCl3).7 The solution of 5 and 8 is brilliant greenish-
yellow, and the fluorescence quantum yield of 5 is the same
as that of PBI. The absorption intensity of compounds 6 and
9 is largely decreased and the fluorescence is highly
quenched, while the absorbance maxima do not show a
significant shift after quaternization (Figure 2b).
We chose 4-pyridylboronic acid as organoboron reagent
for two reasons: it is more stable than 2-pyridylboronic
acid,16 and the desired pyridyl annelated product has higher
symmetry. The reaction of bromo-PBIs with pyridin-4-yl-
boronic acid under Suzuki conditions using Pd(PPh3)4 as the
catalyst, K2CO3 (aqueous 2 M) as the base, and THF as the
solvent, successfully affords pyridyl substituted PBIs in high
yield (82% yield, 30 min for 10, and 69% yield, 4 h for 11);
subsequently exposing to sunlight produces the pyridyl
annelated PBIs (5 and 8) quantitatively (Scheme 1). Remark-
ably, when brominated PBIs are treated with pyridin-4-yl-
boronic acid under the same Suzuki conditions with pro-
longed reaction time (10 h for 5, and 24 h for 8), they directly
afford the desired heterocyclic annelated PBIs in yields of
70% for 5 and 62% for 8. Compared to other aryl substituted
PBIs reported in the literature,7 the pyridyl substitued PBIs
are highly inclined to cyclization, probably by light.
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Antonietti, M.; Bo¨ttcher, C.; Faul, C. F. J. Chem.sEur. J. 2005, 11, 1305.
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Chem., Int. Ed. 2007, 46, 5417. (d) Wu, D.; Pisula, W.; Enkelmann, V.;
Feng, X.; Mu¨llen, K. J. Am. Chem. Soc. 2009, 131, 9620.
(18) You, C.; Dobrawa, R.; Mo¨ller, C. R. S.; Wu¨rthner, F. Top. Curr.
Chem. 2005, 258, 39.
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2005, 127, 18020. (b) Hodgson, P. B.; Salingue, F. H. Tetrahedron Lett.
2004, 45, 685.
230
Org. Lett., Vol. 12, No. 2, 2010

Cyclic voltammetry of heterocyclic annelated PBIs 5 and
8 in CH2Cl2 has been investigated, and each shows one
reversible reduction wave and one quasireversible reduction
wave. Compared with PBI,19 the half-wave reduction po-
tentials vs Fc/Fc+ are -0.99, -1.27 V for 5, and -1.01,
-1.30 V for 8, indicating that the incorporation of pyridine
moieties does not induce a significant shift on electrochemical
behavior.
In conclusion, we report the one-pot synthesis of regiospe-
cifically pyridyl annelated PBIs by combination of the Suzuki
reaction and subsequent light-promoted cyclization. Quat-
ernization on the highly electron-deficient PBI system has
been successfully achieved, and the optical properties of these
positively charged PBIs can be largely tuned. Future work
on the use of more elaborate counterions and metal coordina-
tion to tune their supramolecular organization is currently
underway.
Acknowledgment. For financial support of this research,
we thank the National Natural Science Foundation of China
(Grant 20772131), 973 Program (Grant 2006CB932101,
2006CB806200), Chinese Academy of Sciences, and BASF
SE.
Supporting Information Available: Experimental pro-
cedure and characterization of new compounds. This material
is available free of charge via the Internet at http://pubs.acs.org.
(19) Lee, S. K.; Zu, Y.; Herrmann, A.; Geerts, Y.; Mu¨llen, K.; Bard,
A. J. J. Am. Chem. Soc. 1999, 121, 3513.
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