Synthesis, characterization, and self-assembly of nitrogen-containing heterocoronenetetracarboxylic acid diimide analogues: Photocyclization of N-heterocycle-substituted perylene bisimides

Article abstract of DOI:10.1002/chem.200600605

Novel dibenzocoronenetetra-carboxylic acid diimide analogues and naphthoperylenetetracarboxylic acid diimide analogues containing imidazole, 1,2,4-triazole, and pyrazole rings embedded as functional constituents within the parent hydrocarbon backbone have

Full text of DOI:10.1002/chem.200600605

DOI: 10.1002/chem.200600605
Synthesis, Characterization, and Self-Assembly of Nitrogen-Containing
Heterocoronenetetracarboxylic Acid Diimide Analogues: Photocyclization of
N-Heterocycle-Substituted Perylene Bisimides
Yongjun Li,[a, b] Yuliang Li,*[a] Junbo Li,[a, b] Cuihong Li,[a, b] Xiaofeng Liu,[a, b]
Mingjian Yuan,[a, b] Huibiao Liu,[a] and Shu Wang[a]
Abstract: Novel dibenzocoronenetetra-
carboxylic acid diimide analogues and
ferent influences on the physical prop-
erties of the parent benzocoronene-
C
naphthoperylenetetracarboxylic
diimide analogues containing imid-
azole, 1,2,4-triazole, and pyrazole rings
acid
ACHTREUNG
ACHTREUNG
embedded as functional constituents
within the parent hydrocarbon back-
bone have been synthesized. The p-
rich and p-poor heterocycles have dif-
Keywords: heterocycles
structures perylene
cyclization · self-assembly
·
·
nano-
photo-
·
AHCTREUNG
Introduction
sion of the aromatic core of perylene is a currently active
topic in chemistry,[8] the goal being to extend the range of
application of these chromophores as functional dyes to im-
prove their performance in devices. Perylenetetracarboxylic
acid diimides have been functionalized in one bay region
through the use of Diels–Alder reactions followed by reduc-
tion or mononitration and cyclization,[8b] or through enlarge-
ment of the aromatic p system by palladium-catalyzed ring
annulation.[8c] We have previously developed a phototrig-
gered intramolecular cyclization of 1,7-diphenylperylene di-
Red chromophores based on perylenetetracarboxylic acid
diimide systems have recently attracted considerable investi-
gator attention and have been shown to be suitable in vari-
ous applications, such as fluorescent solar collectors,[1] pho-
tovoltaic devices,[2] dye lasers,[3] molecular switches,[4] and
light-emitting diodes,[5] thanks to their exclusive chemical,
thermal, and photochemical stability and their ability to
self-assemble into extended structures.[6] They were seen to
be highly absorbing in the visible to near-IR region (e
ꢀ105 mÀ1 cmÀ1) and to emit fluorescence with quantum
yields near unity;[7] the interest in these compounds being
largely due to these high fluorescence quantum yields and
their tunable absorption and emission properties. The exten-
A
phores—dibenzocoronenetetracarboxylic acid diimide ana-
logues (BC)—whilst the anellation of perylene-3,4-dicarbox-
ylic acid imide with heterocycles has also been reported.[9]
The physical behavior of p-conjugated materials could be
dramatically modulated through the incorporation of elec-
tron-rich or electron-deficient arenes directly into their con-
jugated backbones. Some recent works have established
self-assembly through strong p–p stacking as an effective
approach to one-dimensional nanostructures based on aro-
matic organic molecules,[10] particularly in larger macrocyclic
aromatic molecules such as hexabenzocoronene.[11] Howev-
er, the substitution of perylene-3,4:9,10-tetracarboxylic acid
diimides (PTIs) with p-rich or p-poor heterocycles as donor
or acceptor moieties has not previously been reported. Imi-
dazoles have been observed to act as good ligands to transi-
tion-metal ions for forming coordinating complexes[12] and
[a] Yj. Li, Prof. Yl. Li, J. Li, C. Li, X. Liu, M. Yuan, Dr. H. Liu,
Prof. S. Wang
Beijing National Laboratory for Molecular Sciences (BNLMS)
CAS Key Laboratory of Organic Solids, Institute of Chemistry
Chinese Academy of Sciences, Beijing 100080 (P.R. China)
Fax : (+86)010-8261-6576
E-mail: ylli@iccas.ac.cn
[b] Yj. Li, J. Li, C. Li, X. Liu, M. Yuan
Graduate School of Chinese Academy of Sciences
Chinese Academy of Sciences, Beijing 100080 (P.R. China)
Supporting information for this article is available on the WWW
under http://www.chemeurj.org/ or from the author.
8378
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FULL PAPER
Here we report a variety of
PTIs substituted with N-hetero-
cycles, together with the synthe-
sis of novel heterocycle-embed-
ded benzocoronenetetracarbox-
ylic acid diimide analogues and
naphthoperylenetetracarboxylic
acid diimide analogues through
the enlargement of the aromat-
ic p systems of available pery-
lene derivatives by photocycli-
zation. These N-heterocycles
and the ligand properties of
imidazole offered us the poten-
the most widely used motif for electron-transport/hole-
blocking functionality is based on the incorporation of elec-
tron affinity-enhancing, nitrogen-containing five-membered
heteroaromatic rings;[13] 1,2,4-triazole was used to enhance
the electron affinity of electron-transport materials,[14]
whereas pyrazole has been used to achieve blue light-emit-
ting diodes.[15]
When coronene derivatives were further functionalized
with carboximide groups, electron-poor aromatic systems
were obtained, to provide electron-transporting n-type ma-
terials.[16] Apart from electron-withdrawing peripheral sub-
stituents, introduction of nitrogen in the core could also
reduce the electron density of the aromatic system. Differ-
ent azaaromatic compounds of varying size, the smallest
being pyridine and triazine units, were found to give rise to
columnar mesophases with different degrees of order,[17]
whereas extended electron-deficient disks based on hexaaza-
triphenylene[18] and quinoxaline[19] cores had charge-carrier
mobility of up to 10À3 cm2 VÀ1 s.[19b]
tial to tune the electron-transporting properties of PTIs for
effective fabrication of devices and easy production of or-
ganic–inorganic hybrid materials. Self-organization of nitro-
gen heterocoronenetetracarboxylic acid diimide systems
may enable the creation of unique aggregate structures as a
result of the stacking of the central perylene rings. We have
detailed the self-assembly behavior of the N-heterocycles
and have established by scanning electron micrograph
(SEM) observation that heterocycle-embedded benzocoro-
nenetetracarboxylic acid diimide systems are able to form
different nanostructures in different solvents.
Results and Discussion
The substitution of 1,7-dibromoperylenetetracarboxylic acid
diimide[20,21] with imidazole, 1,2,4-triazole, and pyrazole moi-
À
eties, connected through their imino N H groups, afforded
2, 4, and 6 by the SNAr amination mechanism (Scheme1).[22]
Scheme 1. Synthesis of the N-heterocycle-substituted perylene diimides and their photocyclization (R=2,6-diisopropylphenyl; 18-c-6=[18]crown-6).
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Y. Li et al.
Compound 2 was obtained in high yield (84%) through
direct heating of a mixture of imidazole and 1,7-dibromoper-
ylenetetracarboxylic acid diimide in toluene, but the reac-
tions of 1,2,4-triazole and pyrazole with 1,7-dibromoperyle-
netetracarboxylic acid diimide had to be in the presence of
K2CO3 and [18]crown-6. In these N-heterocycle-substituted
PTIs, the orientations of the N-heterocycles were restricted
to perpendicular to the perylene units as observed by means
of NMR analysis (the unsubstituted protons in the perylene
bay region were shifted upfield by the N-heterocycles). The
reaction between imidazole and the diimide afforded a mix-
ture of 2 and the monocyclized
determined relative to 1 (Ffl =0.76),[21] although the Stokes
shifts of 2 (55 nm) and 4 (47 nm) were greater than that of 6
(35nm).
After cyclization, 3 showed a sharp band with a defined
structure at l=351 nm, the typical perylene vibronic struc-
ture had disappeared, and four bands at l=453, 468, 517,
and 558 nm were observed in the longer-wavelength region.
A similar phenomenon was observed in the case of 11,
whereas 8 showed the typical absorption structure of diben-
zocoronenetetracarboxylic acid diimide analogues (that is, a
set of bands with defined structures between l=289–337 nm
species, whereas irradiation of 2
produced the doubly cyclized 3.
Substitution of the 1-bromo-
perylene diimide 9 with imid-
À
A
group, directly afforded mono-
cyclized 10 without the inter-
mediate (Scheme 2). Analysis
of the monocyclized product by
high-resolution fast-atom bom-
bardment (HRFAB) mass spec-
trometry indicated the expected
mass ion with loss of two hy-
drogen atoms. The side of the
plane at which the imidazole
Scheme 2. Synthesis of heterocycle-embedded naphthoperylenetetracarboxylic acid diimides 10 and 11 (R=
2,6-diisopropylphenyl).
ring had been bonded was clearly shown by four singlets at
1
d=10.32, 9.54, 8.78, and 8.21 ppm. The H NMR spectra of
the doubly cyclized 3 (Scheme 1) were characterized by four
singlets (each representing two hydrogens) at d=10.47, 9.80,
8.93, and 8.26 ppm.
The triazole and pyrazole groups could also be cyclized
onto the perylene main core, though at relatively slow rates
(in the case of triazole, monocyclized 7 and doubly cyclized
8 were obtained, whereas in that of pyrazole only monocycl-
ized product was separated).
All of these compounds were highly soluble in various or-
ganic solvents, such as CH2Cl2, CHCl3, toluene, and acetone,
except in the case of the cyclized product 3, which only dis-
solved readily in CH3CN, pyridine, and DMSO.
Room-temperature absorption and emission spectra of
these compounds are shown in Figure 1 and their photo-
physical properties are summarized in Table 1. Compounds
2, 4, and 6 showed the characteristic vibronic fine structure
of the perylene core p–p* transition. Because of the steric
constraints, the orientations of the imidazole, triazole, and
pyrazole moieties were restricted to orthogonal to the pery-
lene ring, so the p-conjugative interactions were minimal, as
a consequence of which the lmax value for 2 was only slightly
redshifted (by 8 nm) relative to that for the dibromoperyle-
netetracarboxylic acid diimide 1 (527 nm).[21] The lmax of 4
was redshifted by 12 nm to 539 nm, due to the electron-
donor properties of the pyrazole unit, whilst the lmax of 6
was blueshifted by 3 nm to 524 nm, due to the electron affin-
ity of the triazole moiety. These N-heterocycle-substituted
derivatives all fluoresced with quantum yields Ffl >0.3, as
Figure 1. Absorption and emission spectra of the photocyclized N-hetero-
cycle-substituted perylenes and their precursors.
8380
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Heterocoronenetetracarboxylic Acid Diimide Analogues
FULL PAPER
Table 1. Photophysical and electrochemical properties of the photocyclized heterocycle-substituted perylenes
and their precursors.
two irreversible oxidation po-
tentials, at 1.25and 1.55V. The
oxidation potentials of 2 and 4
were lower than those of 1,7-di-
bromo-N,N’-bis(2,6-diisopropyl-
phenyl)perylene-3,4:9,10-tetra-
carboxylic acid diimide (1),
which clearly indicated the sig-
nificant HOMO-raising effect
of using p-electron-rich imida-
zole and pyrazole units as con-
stitutional moieties. The oxida-
tion potential of 6, however,
was a little higher than that of
1, which may be due to the p-
electron-deficient 1,2,4-triazole
moiety rendering oxidation
more difficult. The N-heterocy-
cle-substituted perylene deriva-
[c]
Abs[a]
lmax [nm]
PL[b]
Ffl
E =
E =
red
HOMO/LUMO
[eV][f]
1
1
2
ox
2
lmax [nm] [%] [V vs Fc/Fc+][e]
[V vs Fc/Fc+][e]
1
2
3
527
535
558, 468, 351
547
590
587
575
559
522
498
586
591
76
33
49
43
69
1.50
1.40
1.32
1.29
1.53
À0.67, À0.89
À0.65, À0.89
À6.30/À4.13
À6.20/À4.15
À0.78, À0.94, À1.07 À6.12/À4.02
À0.76, À0.87, À1.04 À6.09/À4.04
10 554, 511, 485, 350
6
7
8
4
5
524
505, 315
492, 460, 433, 337, 332,
539, 504, 391
565, 526, 450, 424, 316
À0.56, À0.81
À6.33/À4.24
70[d] 1.62
74[d] 1.49
À0.53, À0.64, À0.89 À6.42/À4.27
À0.56, À0.74, À1.01 À6.29/À4.24
54
41
50
1.55, 1.25
1.59, 1.36
1.45, 1.32
À0.65, À0.89
À6.05/À4.15
À0.67, À0.77, À0.95 À6.16/À4.13
À0.71, À0.84, À1.00 À6.12/À4.09
11 560, 524, 445, 418, 397, 316 583
[a] In CHCl3. [b] In CHCl3, upon excitation at the absorption maximum. [c] In CHCl3, N,N’-bis(2,6-diisopropyl-
phenyl)-1,7-dibromoperylene-3,4:9,10-tetracarboxylic acid diimide (Ffl =0.76 in CHCl3[21]) as the standard.
[d] In CHCl3, dibenzocoronenetetracarboxylic acid diimide (Ffl =0.80 in CHCl3[8c]) as the standard. [e] In
CH3CN containing 0.05m nBu4NPF6 as a supporting electrolyte. [f] HOMO and LUMO levels with respect to
zero vacuum level were estimated directly from CV data.
and the typical perylene vibronic structure with a maximum
absorption band at l=492 nm, hypsochromically shifted by
32 nm). Compound 8 emitted an intensive green-yellow flu-
orescence with a maximum (in CHCl3) at 498 nm, hypso-
tives all showed two reversible, well separated, one-electron
reduction waves, with the imidazole and pyrazole moieties
only inducing positive shifts of 20 mV. Compound 6 showed
a larger positive shift in its redox potential (110 mV).
After cyclization there were two one-electron waves and
one two-electron reduction wave (Figure 2), and the first re-
duction potential of 3 was negatively shifted by about
130 mV. The first reduction potential of 8 was unchanged,
whereas that of 5 was negatively shifted a little (20 mV).
The oxidation process was irreversible, similarly to the cases
of irreversible oxidation observed for other azaaromatic
conjugated systems and attributable to oxidation processes
involving the nitrogen lone pairs.[23] There was a tendency of
the imidazole- and pyrazole-substituted perylenes (cyclized
or not) to be more easily oxidized, whereas the triazole-sub-
stituted perylene (and the cyclized product) were more diffi-
cult.
Table 1 also lists the HOMO and LUMO energy levels of
these compounds, taken directly from the cyclic voltamma-
grams. The electronic structure of the parent perylene-
3,4:9,10-tetracarboxylic acid diimide was perturbed signifi-
cantly after its substitution with N-heterocycles. Substitution
of the backbone with electron-rich heterocycles such as imi-
dazole and pyrazole effectively extended the p-conjugation,
raising the HOMO level and lowering the LUMO level, re-
sulting in a smaller energy gap. Upon embedding of elec-
tron-deficient 1,2,4-triazole as a constituent moiety, this
modification resulted in shifts of both the HOMO and
LUMO levels to lower levels. Upon cyclization, the HOMO
and LUMO levels of cyclized compounds tended to be
raised.
chromically shifted by about 61 nm in relation to
6
(559 nm). In the case of the imidazole-substituted perylene,
the cyclization had a negligible influence on the emission
maxima. More interestingly, in the monocyclized product
obtained from the pyrazole-substituted perylene, the lmax
was redshifted, and a set of new bands (360–460 nm) had ap-
peared in the trough region of the original perylene or di-
benzocoronene analogues, so the absorption bands of the cy-
clized pyrazole-substituted perylene system spanned a wide
range of the UV and visible spectrum, from 300 to 600 nm,
making it an ideal system for harvesting polychromatic light.
The emission of 5 was only slightly redshifted.
Cyclic voltammetry (CV) was used to examine the elec-
trochemical behavior of N-heterocycle-substituted perylenes
and their photocyclized analogues (Figure 2; Table 1). Com-
pounds 2 and 6 each exhibited one irreversible oxidation po-
tential, at 1.40 and 1.53 V, respectively, whereas 4 exhibited
Upon cyclization, the compoundsꢁ coordination abilities
disappeared, due to the dispersion of the nitrogen lone pairs
over the whole aromatic plane, but with the increase in the
size of the core aromatic system, the p–p stacking of the
perylene backbones was enhanced. Lengthy p-conjugated
oligomers have been utilized as building blocks for the for-
mation of well-defined supramolecular structures,[24] organi-
Figure 2. Cyclic voltammograms of the photocyclized heterocycle-substi-
tuted perylenes and their precursors.
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Y. Li et al.
zation of p-conjugated oligomers having been achieved by
utilization of thermotropic and lyotropic liquid crystallinity,
self-assembly of block copolymers, and complexation
through noncovalent bonds such as hydrogen bonds.[25] Or-
ganizational control over the orientation of p-conjugated
oligomers is important for the development of nanoscopic
molecular systems.
field shift effects with increasing temperature were assigned
to the perylene protons (A and B), as indicated in Figure 3.
From the above results, we were able to infer that 3 can
self-assemble in polar solvents through p–p interactions,
forming rodlike oligomers, and that additional solvophobic
forces can further strengthen attractive intermolecular stack-
ing. We were also able to propose a model for the aggregate
behavior of 3 (Figure 3b,c). Because of the steric hindrance
between 2,6-diisopropylphenyl groups in the case of parallel
stacking and the steric hindrance between 2,6-diisopropyl-
phenyl group and imidazole in the case of cross-stacking,
the two adjacent molecules are stacked with an angle of
aberration of about 458. Rate constants[27] (k) for 3 were de-
termined by using proton lineshape analysis,[28] and an
Eyring plot[29] (Figure 4) was constructed to estimate the
thermodynamic parameters. The enthalpy of activation
(DH°) was found to be +56.8 kJmolÀ1, and the entropy of
activation (DS°) was found to be À61.4 JmolÀ1 KÀ1.
The enlarged PTI molecules favored the formation of
nanostructures along one di-
It was speculated that the combination of a p-rich N-het-
erocycle with a p-conjugated perylene core might give rise
to unique aggregation behavior because of their intermolec-
1
ular p–p interactions, and this was confirmed by H NMR
and SEM studies as shown below. Compound 3 is also an
amphiphile, as the imidazole units exhibit hydrophilic prop-
erties and the perylene core shows hydrophobic interactions
in specific solvent environments.[26]
1H NMR spectra of 3 were measured in CDCl3 and
[D6]DMSO, and their expanded aromatic regions are shown
in Figure 3. In CDCl3, peaks at d=10.47 and 9.80 ppm were
assigned to the perylene protons (A and B), and peaks at
mension: the red color of a sol-
ution of 3 in CH3CN (10À4 m)
became weak and some precipi-
tates were observed after the
system had been kept at room
temperature for one week. The
precipitates were dispersed in
CH3CN by means of ultrasonifi-
cation and cast on a silicon
slide for SEM measurement,
with the obtained SEM images
showing well-defined rhombic
structures as shown in Figure
5A. Direct casting of the solu-
tion of 3 in CH3CN (5”10À5 m)
on the silicon slide resulted in
uniform nanofiber structures
(Figure 5B). Similar nanofiber
structures were also found in
Figure 3. a) 1H NMR spectrum (400 MHz) of 3 in CDCl3 (top), and temperature-dependent 1H NMR spectra
of 3 recorded at 300 MHz in [D6]DMSO. Side view (b) and top view (c) models for the aggregation behavior
of 3.
d=8.93 and 8.26 ppm were assigned to the cyclized imid-
azole protons (C and D). In [D6]DMSO at room tempera-
ture, there were two sharp peaks at 8.15and 9.64 ppm and
one broad peak at d=9.0–9.4 ppm, whereas the peak for the
protons at the 3,5-positions in the 2,6-diisopropylphenyl
moiety was also broadened. This room-temperature NMR
spectrum implied dynamic processes on the NMR timescale,
so variable-temperature NMR spectra of 3 were recorded in
[D6]DMSO, allowing for
a wide temperature window
(Figure 3). As the temperature was increased, the broad
peak at d=9.0–9.4 ppm became sharp and was shifted to
9.58 ppm, the peak at 9.64 ppm was split into two peaks, one
shifted to 9.89 ppm and the other to 9.48 ppm, the peak at
8.15ppm experienced no changes, and the broad peak for
the protons at the 3,5-position in the 2,6-diisopropylphenyl
moiety became sharp. The peaks displaying evident down-
Figure 4. Eyring plot for 3 obtained by proton lineshape analysis.
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Heterocoronenetetracarboxylic Acid Diimide Analogues
FULL PAPER
Experimental Section
Unless stated otherwise, all reagents and anhydrous solvents were pur-
chased from Aldrich Chemicals and were used without further purifica-
tion. 1-Bromo-N,N’-bis(2,6-diisopropylphenyl)perylene-3,4:9,10-tetracar-
boxylic acid diimide[32] was prepared as described in the literature.
Column chromatography (CC): silica gel (160–200 meshes). TLC glass
plates coated with silica (F254) were visualized under UV light. 1H and
13C NMR spectra were recorded on a Bruker AV 400 instrument, at a
constant temperature of 258C. Chemical shifts are reported in parts per
million from low to high field and are referenced to tetramethylsilane
(TMS). Matrix-assisted laser desorption/ionization time-of-flight
(MALDI-TOF) mass spectrometric measurements were performed on a
Bruker Biflex III MALDI-TOF instrument, UV/Vis spectra were meas-
ured on a Hitachi U-3010 spectrometer, and FTIR spectra were recorded
as KBr pellets on a Perkin–Elmer System 2000 spectrometer. Fluores-
cence excitation and emission spectra were recorded with a Hitachi F-
4500 FL fluorimeter at a constant temperature of 258C.
General method for photocyclization: Compounds for cyclization (0.01–
0.02 mmol) were dissolved in CH2Cl2 (20 mL) in a quartz vessel. The sol-
ution was directly irradiated in sunlight, the progress being monitored by
TLC. After the photocyclization was complete the reaction mixture was
concentrated under reduced pressure to afford the crude product, which
was purified by using column chromatography.
Figure 5. SEM images of 3: A) rhombic structures precipitated from
CH3CN, together with nanofibers (gold stained) cast from B) CH3CN,
D) pyridine, and C) a nanofiber network from an n-hexane/pyridine mix-
ture. The scale bars of the insets in A and D represent 1 mm.
Cyclic voltammetry (CV): For this work, CV experiments were per-
formed at a scan rate of 10 mVsÀ1, with use of a glassy carbon electrode
as a working electrode and Ag/AgCl as a reference electrode. CV was
performed in CH3CN with nBu4NPF6 (0.05m) as a supporting electrolyte,
the case of a pyridine solution (Figure 5D), except that the
nanofibers tended to grow from some kernels. We also ob-
tained a nanofiber network by using the liquid/liquid diffu-
sion method: n-hexane was used to cover the solution of 3
in pyridine, a large quantity of entangled nanofibers being
obtained after diffusion for three days (Figure 5C). For com-
parison, we also recorded images of the electron-deficient
1,2,4-triazole-decorated perylene, for which only irregular
structures were found (see the Supporting Information, Fig-
ure S3). This lack of one-dimensional self-assembly may be
due to the electron-deficiency of the p-conjugated perylene
core. We can therefore control the self-assembly capability
of the p-conjugated perylene core by decoration with N-het-
erocycles, and can further control the aggregate structures
by tuning the solvents.
+
1
in which the ferrocene/ferrocenium ion (Fc/Fc ) redox couple gives E =
=
2
0.40 V. The HOMO and LUMO energy levels can be deduced by using
the following:[30] HOMO [eV]=[À4.8À(HOMO of ferrocene with re-
spect to the zero vacuum level[31])À(E = of the first oxidation potential)+
1
2
1
(0.40)]; LUMO [eV]=[À4.8À(E = of the first reduction poten-
2
tial)À(0.40)].
N,N’-Bis(2,6-diisopropylphenyl)-1,7-bis(imidazol-1-yl)perylene-3,4:9,10-
tetracarboxylic acid diimide (2): A mixture of 1,7-dibromo-N,N’-bis(2,6-
diisopropylphenyl)perylene-3,4:9,10-tetracarboxylic acid diimide (158 mg,
0.2 mmol) and imidazole (136 mg, 2 mmol) in toluene was stirred at
1008C for 10 h. After cooling to room temperature, the mixture was
washed with water, the organic phase was dried with Na2SO4, the solvent
was removed by reduced pressure, and the crude product was obtained.
Purification was accomplished by using column chromatography on silica
gel with CH2Cl2/CH3OH (10:1) to give
2
(141 mg, 84%). 1H NMR
(400 MHz, CDCl3): d=8.71 (s, 2H), 8.48 (d, J=8.1 Hz, 2H), 7.76 (s, 2H),
7.53–7.49 (m, 4H), 7.35 (d, J=7.8 Hz, 4H), 7.31 (s, 2H), 7.11 (d, J=
8.1 Hz, 2H), 2.71 (sept, J=6.7 Hz, 4H), 1.17 ppm (d, J=6.7 Hz, 24H);
13C NMR (100 MHz, CDCl3): d=162.6, 162.4, 145.5, 135.7, 134.8, 133.0,
132.9, 132.2, 131.2, 130.0, 129.9, 129.8, 129.4, 128.7, 127.9, 124.4, 124.3,
123.1, 118.3, 29.3, 24.0 ppm; IR (KBr): n˜ =1709, 1670, 1596, 1428, 1340,
Conclusion
1249, 1199, 1145, 1032, 909, 733 cmÀ1
C54H46N6O4: 842.35; found: 842.3.
; MS TOF: m/z calcd for
In conclusion, we have established efficient syntheses of
novel heterocycle-embedded (3 and 8) benzocoronenetetra-
carboxylic acid diimide analogues and naphthoperylenete-
tracarboxylic acid diimide analogues (5, 10, and 11). The
physical properties of the parent benzocoronenetetracarbox-
ylic acid diimide and naphthoperylenetetracarboxylic acid
diimide units were significantly altered through the intro-
duction of p-rich or p-poor heterocycles as constituents. The
p-rich 3 was able to self-assemble into one-dimensional
nanostructures as a result of strong p–p stacking, while the
p-poor 8 lacked the one-dimensional self-assembly capabili-
ty, which offered us the potential to control the self-assem-
bly capability of the p-conjugated perylene core through
decoration with N-heterocycles, and also to control the ag-
gregate structures further by tuning of the solvents.
N,N’-Bis(2,6-diisopropylphenyl)-1,7-bis(triazol-1yl)perylene-3,4:9,10-tet-
racarboxylic acid diimide (6): mixture of 1,2,4-triazole (138 mg,
A
2 mmol), anhydrous potassium carbonate (55 mg, 0.4 mmol), and
[18]crown-6 (105mg, 0.4 mmol) was stirred in toluene (50 mL) at room
temperature, and 1,7-dibromo-N,N’-bis(2,6-diisopropylphenyl)perylene-
3,4:9,10-tetracarboxylic acid diimide (158 mg, 0.2 mmol) was added. The
reaction mixture was heated at reflux under nitrogen with stirring for
12 h. After the system had cooled to room temperature, the solvent was
removed under reduced pressure and the crude product was obtained.
Purification was accomplished by using column chromatography on silica
gel with CH2Cl2 to give 6 (152 mg, 90%). 1H NMR (600 MHz, CDCl3):
d=8.80 (s, 2H), 8.51 (d, J=8.0 Hz, 2H), 8.50 (s, 2H), 8.41 (s, 2H), 7.52
(t, J=8.7 Hz, 2H), 7.36 (d, J=8.8 Hz, 4H), 7.05(d, J=8.0 Hz, 2H), 2.71
(sept, J=6.6 Hz, 4H), 1.19–1.16 ppm (m, 24H); 13C NMR (100 MHz,
CDCl3): d=162.6, 162.3, 145.6, 137.9, 134.3, 132.7, 132.3, 131.2, 130.1,
130.0, 129.9, 129.1, 129.0, 128.4, 128.3, 125.3, 124.4, 124.3, 123.4, 29.3,
24.0 ppm; IR (KBr): n˜ =1710, 1671, 1596, 1504, 1466, 1444, 1418, 1388,
Chem. Eur. J. 2006, 12, 8378 – 8385ꢀ 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
8383

Y. Li et al.
1340, 1250, 1197, 1146, 1010, 913, 733 cmÀ1; MS TOF: m/z calcd for
C52H44N8O4: 844.35; found: 844.4.
plished by using column chromatography on silica gel with CH2Cl2 to
give 10 (12 mg, 78%). 1H NMR (400 MHz, CDCl3): d=10.32 (s, 1H),
9.54 (s, 1H), 9.30 (d, J=8.2 Hz, 1H), 9.25(d, J=8.2 Hz, 1H), 9.12 (d, J=
8.2 Hz, 2H), 8.78 (s, 1H), 8.21 (s, 1H), 7.59–7.52 (m, 2H), 7.43–7.38 (m,
4H), 2.86–2.79 (m, 4H), 1.23–1.20 ppm (m, 24H); IR (KBr): n˜ =1712,
1672, 1597, 1436, 1357, 1326, 1253, 1195, 1149, 838, 812, 741 cmÀ1; HRMS
(FAB+): m/z calcd for C51H42N4O4: 774.3206; found: 774.3208 [M]+.
N,N’-Bis(2,6-diisopropylphenyl)-1,7-bis(pyrazol-1-yl)perylene-3,4:9,10-
tetracarboxylic acid diimide (4): A mixture of pyrazole (136 mg, 2 mmol),
anhydrous potassium carbonate (55 mg, 0.4 mmol), and [18]crown-6
(105mg, 0.4 mmol) was stirred in toluene (50 mL) at room temperature
and 1,7-dibromo-N,N’-bis(2,6-diisopropylphenyl)perylene-3,4:9,10-tetra-
carboxylic acid diimide (158 mg, 0.2 mmol) was added. The reaction mix-
ture was heated at reflux under nitrogen with stirring for 12 h. After the
system had cooled to room temperature, the solvent was removed under
reduced pressure and the crude product was obtained. Purification was
accomplished by using column chromatography on silica gel with CH2Cl2
to give 4 (148 mg, 88%). 1H NMR (400 MHz, CDCl3): d=8.82 (s, 2H),
8.44 (d, J=8.0 Hz, 2H), 7.93 (d, J=1.9 Hz, 2H), 7.84 (d, J=1.9 Hz, 2H),
7.51 (t, J=7.8 Hz, 2H), 7.35(d, J=7.8 Hz, 4H), 6.84 (d, J=8.0 Hz, 2H),
6.72–6.70 (m, 2H), 2.73 (sept, J=6.8 Hz, 4H), 1.17 ppm (d, J=6.8 Hz,
24H); 13C NMR (100 MHz, CDCl3): d=163.1, 162.7, 145.6, 143.3, 138.0,
133.4, 131.6, 131.2, 130.2, 130.1, 130.0, 129.9, 129.3, 128.5, 128.4, 124.2,
123.9, 122.8, 110.2, 29.3, 24.0 ppm; IR (KBr): n˜ =1707, 1669, 1594, 1460,
1338, 1246, 1196, 1150, 745 cmÀ1; MS TOF: m/z calcd for (C54H46N6O4):
842.35; found: 842.5.
Compound 11: A mixture of pyrazole (13.6 mg, 0.2 mmol), anhydrous po-
tassium carbonate (5.5 mg, 0.04 mmol), and [18]crown-6 (10 mg,
0.04 mmol) was stirred in toluene (20 mL) at room temperature and 1-
bromo-N,N’-bis(2,6-diisopropylphenyl)perylene-3,4:9,10-tetracarboxylic
acid diimide (15mg, 0.02 mmol) was added. The reaction mixture was
heated at reflux under nitrogen with stirring for 12 h. After the system
had cooled to room temperature, the solvent was removed under reduced
pressure, and the crude product was obtained. Purification was accom-
plished by using column chromatography on silica gel with CH2Cl2 to
give 11 (10 mg, 66%). 1H NMR (400 MHz, CDCl3): d=10.15(s, 1H),
9.55 (s, 1H), 9.21–9.16 (m, 2H), 9.09–9.03 (m, 2H), 8.50 (d, J=1.9 Hz,
1H), 7.66 (d, J=1.9 Hz, 1H), 7.57–7.52 (m, 2H), 7.42–7.39 (m, 4H),
2.87–2.82 (m, 4H), 1.25–1.20 ppm (m, 24H); IR (KBr): n˜ =1712, 1673,
1595, 1459, 1410, 1328, 1254, 1194, 914, 810, 744 cmÀ1; HRMS (FAB+):
m/z calcd for C51H42N4O4: 774.3206; found: 774.3209 [M]+.
Compound 7: Compound 6 (0.02 mmol) in CH2Cl2 (20 mL) was irradiat-
ed in sunlight for about 2 d. The solution became yellow, the solvent was
removed by reduced pressure, and the crude product was obtained. Puri-
fication was accomplished by using column chromatography on silica gel
with CH2Cl2 to give 7 (85%). 1H NMR (400 MHz, CDCl3): d=10.29 (s,
1H), 10.17 (s, 1H), 9.07 (s, 1H), 8.93 (s, 1H), 8.79 (d, J=8.4 Hz, 1H),
8.65 (s, 1H), 8.56 (s, 1H), 7.56–7.53 (m, 2H), 7.41 (t, J=8.0 Hz, 4H), 7.30
(d, J=8.4 Hz, 1H), 2.79 (sept, J=6.9 Hz, 4H), 1.24–1.18 ppm (m, 24H);
IR (KBr): n˜ =1716, 1676, 1602, 1462, 1363, 1334, 1266, 1013, 839, 815,
740, 713 cmÀ1; MS TOF: m/z calcd for C52H42N8O4: 842.33; found: 842.4.
Acknowledgements
This work was supported by the Major State Basic Research Develop-
ment Program and the National Natural Science Foundation of China
(grants 20531060, 10474101, 20418001, 20473102, and 20421101).
Compound 8: Compound 6 (0.02 mmol) in CH2Cl2 (20 mL) was irradiat-
ed in the sun for about 6 d. The solution became yellow, the solvent was
removed by reduced pressure, and the crude product was obtained. Puri-
fication was accomplished by using column chromatography on silica gel
with CH2Cl2 to give 8 (40%). 1H NMR (400 MHz, CDCl3): d=10.52 (s,
2H), 10.51 (s, 2H), 9.03 (s, 2H), 7.63–7.58 (m, 2H), 7.46 (d, J=7.8 Hz,
4H), 2.95–2.85 (m, 4H), 1.26–1.19 ppm (m, 24H); IR (KBr): n˜ =1715,
1675, 1509, 1463, 1320, 1256, 1180, 822, 746 cmÀ1; HRMS (FAB+): m/z
calcd for C52H40N8O4+H: 841.3251; found: 841.3251 [M+H]+.
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Compound 3: Compound 2 (0.1 mmol) in CH2Cl2 (20 mL) was irradiated
in the sun for about 3 h. The solvent was removed by reduced pressure
and the crude product was obtained. Purification was accomplished by
using column chromatography on silica gel with CH2Cl2 to give 3 (61 mg,
75%). 1H NMR (400 MHz, CDCl3): d=10.47 (s, 2H), 9.80 (s, 2H), 8.93
(s, 2H), 8.26 (s, 2H), 7.60 (t, J=7.9 Hz, 2H), 7.44 (d, J=7.9 Hz, 4H),
2.95–2.80 (m, 4H), 1.27–1.23 ppm (m, 24H); IR (KBr): n˜ =1715, 1677,
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m/z calcd for C54H42N6O4+H: 839.3346; found: 839.3355 [M+H]+.
Compound 5: Compound 4 (0.02 mmol) in CH2Cl2 (20 mL) was irradiat-
ed in the sun for about 3 d. The solvent was removed under reduced
pressure, and the crude product was obtained. Purification was accom-
plished by using column chromatography on silica gel with CH2Cl2 to
give 5 (75%). 1H NMR (400 MHz, CDCl3): d=10.16 (s, 1H), 9.62 (s,
1H), 8.98 (s, 1H), 8.64 (d, J=8.4 Hz, 1H), 8.52 (d, J=1.8 Hz, 1H), 8.06
(s, 1H), 7.95(s, 1H), 7.70 (d, J=1.8 Hz, 1H), 7.58–7.51 (m, 2H), 7.42–
7.37 (m, 4H), 6.99–6.88 (br, 1H), 6.84 (s, 1H), 2.88–2.73 (m, 4H), 1.23–
1.17 ppm (m, 24H); IR (KBr): n˜ =1713, 1674, 1600, 1520, 1458, 1407,
1336, 1249, 1198, 922, 814, 738 cmÀ1; HRMS (FAB+): m/z calcd for
C54H44N6O4: 840.3424; found: 840.3400 [M]+.
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8384
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ꢀ 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2006, 12, 8378 – 8385

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Chem. Eur. J. 2006, 12, 8378 – 8385ꢀ 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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