An efficient synthesis of heptaaryldipyrromethenes from tetraarylcyclopentadienones and ammonium acetate and their extension to the corresponding BODIPYs

Article abstract of DOI:10.1039/c2ob26509e

Heptaaryldipyrromethenes are efficiently prepared from ammonium acetate and tetraarylcyclopentadienones in a one-pot cascade process and can be converted into heptaaryl BODIPYs with fluorescent response to environmental acidity.

Full text of DOI:10.1039/c2ob26509e

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PAPER
An efficient synthesis of heptaaryldipyrromethenes from
tetraarylcyclopentadienones and ammonium acetate and their extension to
the corresponding BODIPYs†
Jichao Li, Binbin Hu, Gongfang Hu, Xihui Li, Ping Lu* and Yanguang Wang*
Received 1st August 2012, Accepted 17th September 2012
DOI: 10.1039/c2ob26509e
Heptaaryldipyrromethenes are efficiently prepared from ammonium acetate and
tetraarylcyclopentadienones in a one-pot cascade process and can be converted into heptaaryl BODIPYs
with fluorescent response to environmental acidity.
traditional methods was seldom reported due to the lack of the
Introduction
triarylated pyrrole precursor which was not easily accessible.14
Both porphyrin1 and boron-dipyrromethene (BODIPY)2 are
Here we would like to report an efficient synthesis of heptaaryl-
important in life science and material science. As the key struc-
ture of porphyrin and BODIPY, dipyrromethenes (dipyrrins)
themselves are also versatile molecules in many disciplines.
They can bind to divalent tin and emit reversible fluorescence
via anion exchange between triflate and chloride,3 function as
the bridge in liquid crystalline conjugated polymers,4 exhibit
highly fluorogenic complexation with metal ions,5 diastereo-
selectively form double-helicate structures with divalent zinc,6
generate triple-stranded helicates with trivalent metals,7 and
work as ligands for self-assembly in supramolecular chemistry.8
Due to the significant importance of dipyrromethenes, their syn-
thesis has attracted much attention.2 Dipyrromethenes are nor-
mally prepared by the oxidation of dipyrrolemethanes that were
condensed from the appropriate pyrroles and aromatic aldehydes
in the presence of acid.9 As an alternative method, they could
also be directly condensed from suitable pyrroles and an acti-
vated carboxylic acid derivative, such as acyl chloride.10 In
asymmetrical dipyrromethene synthesis, 2-formyl pyrrole was
previously prepared to fuse a different pyrrole in order to have
multifunctionalities.11 Only a few methods described in literature
leading to the construction of dipyrromethenes, began with
ammonium acetate as nitrogen source,12 while most of others
started from pyrroles. For instance, a special dipyrrolemethene,
in which two pyrroles were respectively fused with two
benzenes, was prepared from a dione and ammonium acetate
based on Paal–Knorr pyrrole synthesis.13 On the other hand, syn-
thesis of heptaaryldipyrromethenes and their BODIPYs by
dipyrromethenes, starting from tetraarylcyclopentadienones and
ammonium acetate by eliminating one mole of aryl aldehyde and
their further extension to heptaaryl BODIPYs.
Results and discussion
In the study of the reaction between tetraphenylcyclopentadie-
none (1a) and phenanthrene-9,10-dione in the presence of
ammonium acetate in refluxing acetic acid, we isolated a com-
pound in 82% yield with an accurate molecular weight of
676.2875. In order to elucidate the structure and solve the solubi-
lity problem, we tested 3,4-bis(4-n-butylphenyl)-2,5-diphenyl-
cyclopenta-2,4-dienone (1b) under the same reaction conditions.
The reaction serendipitously constructed 2b with a useful
dipyrromethene core, while phenanthrene-9,10-dione did not
participate in the reaction. The structure of 2b was established by
X-ray analysis of its single crystal (Scheme 1).15
Department of Chemistry, Zhejiang University, Hangzhou 310027,
P. R. China. E-mail: pinglu@zju.edu.cn; Fax: (+86) 571-87952543
†Electronic supplementary information (ESI) available: Detailed exper-
imental procedures, characterization data, copies of 1H and 13C NMR
spectra, and measurement of photophysical properties. CCDC 861954.
For ESI and crystallographic data in CIF or other electronic format see
DOI: 10.1039/c2ob26509e
Scheme 1 ORTEP image of the single crystal structure of 2b.
8848 | Org. Biomol. Chem., 2012, 10, 8848–8859
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Table 1 Substrate diversity for the formation of 2 and their extension
to 3
2a, yieldc
(%)
3b, yieldc
(%)
Entry
1 (Ar1, Ar2)
1
2
3
4
5
6
7
8
1a (C6H5, C6H5)
1b (4-n-BuC6H4, C6H5)
2a, 82
2b, 73
2c, 70
2d, 74
2e, 71
2f, 61
2g, 63
2h, 53
2i, 68
2j, 52
2k, 75
2l, 76
2m, 71
2n, 66
3a, 94
3b, 93
3c, 94
3d, 95
3e, 93
3f, 91
3g, 90
3h, 92
3i, 92
3j, 89
3k, 94
3l, 92
3m, 91
3n, 92
1c (4-n-BuC6H4, 4-CH3OC6H4)
1d (4-n-BuC6H4, 4-CH3C6H4)
1e (4-n-BuC6H4, 4-BrC6H4)
1f (4-n-BuC6H4, 4-CF3C6H4)
1g (4-n-BuC6H4, 4-FC6H4)
1h (4-n-BuC6H4, 4-PhC6H4)
1i (4-n-BuC6H4, 3-CH3OC6H4)
1j (C6H5, 4-n-BuOC6H4)
1k (C6H5, 4-t-BuC6H4)
Scheme 2 A tandem process for the formation of 2 from 1 and
NH4OAc.
9
10
11
12
13
14
A possible mechanism for this transformation is postulated
(Scheme 2). Initially, ammonia nucleophilically attacked 1 via
aza-Michael addition and generated A. A retro aldol conden-
sation cleaved the C–C bond and led to the formation of B
which was further converted into C by intramolecular enamine
formation. Hydration of C led to the formation of D. A stable
1,2,3-triarylpyrrole E was produced by eliminating an aryl
aldehyde. E nucleophilically attacked C and formed the hepta-
aryl dipyrrolemethane F. After spontaneous dehydrogenation, 2
was prepared in moderate to good yields. The eliminated aryl
aldehyde was detected by GC-MS in the cases of the preparation
of 2a and 2b (Fig. S56–S57†).
1l (C6H5, 3-CH3OC6H4)
1m (4-CH3C6H4, 4-n-BuOC6H4)
1n (4-BrC6H4, 4-n-BuOC6H4)
a 1 (1 mmol), NH4OAc (20 mmol), and HOAc (2 mL) were mixed and
refluxed for 20 h. b 2 (1 mmol), Et3N (15 mmol), BF3·Et2O (18 mmol),
and DCM (100 mL) were mixed and refluxed for 2 h. c Isolated yield.
We then optimized the reaction conditions based on the reac-
tion between 1b16 and ammonium acetate (Table S1†). It was
observed that increasing the molar ratio of ammonium acetate to
cyclopentadienone, raising the reaction temperature and exten-
sion of the reaction time increased the yield. The highest yield of
2b (73%) could be obtained by refluxing a mixture of
ammonium acetate (20 mmol) and 1b (1 mmol) in acetic acid
(2 mL) for 20 h. Ammonium chloride afforded 2b, but in a rela-
tively lower yield (57%) under the same reaction conditions,
while lots of spots on TLC plate were observed by using
ammonium formate as the nitrogen source.
The fact that BODIPYs have wide applications while the
photophysical properties of heptaaryl BODIPYs14,17 are seldom
reported encouraged us to utilize the synthesized heptaaryldipyrro-
methenes to make heptaaryl BODIPYs following published
methods.18 The results are summarized in Table 1. Thus, 3a–3n
were obtained in excellent yields and their structures were
1
confirmed by H NMR and 13C NMR spectroscopy (Fig. S52–
S76†) and HRMS.
Under the optimized reaction conditions, we tested the diver-
sity of cyclopentadienones (1). Heptaaryldipyrromethenes (2)
were isolated in yields ranging from 52 to 82% (Table 1) and
Due to the solubility problem in isolating 2, we developed a
two-step, one-pot straightforward process for the preparation of
3. Without the purification of the crude products, the reaction
mixtures could be directly converted into the corresponding
BODIPYs by adding triethylamine and trifluoroboroetherate.
In this way, 3o and 3p were prepared in 61% and 64% yields,
respectively (Scheme 3).
Heptaaryldipyrromethene with bromo substitution, such as 2e,
could be extended into 4a and 4b via Suzuki coupling with
p-tolylboronic acid or (4-methoxyphenyl)boronic acid respecti-
vely. They can be further converted into heptaaryl BODIPYs 5a
and 5b (Scheme 4). Crude heptaaryldipyrromethene with bromo
substitution could be transferred into 4c and 4d via Sonogashira
coupling with 4-n-butylphenyl acetylene, and be further con-
verted into heptaaryl BODIPYs 5c and 5d (Scheme 5).
1
their structures were characterized by H, 13C NMR, and HRMS
(Fig. S27–S49†). The yield was slightly influenced by the substi-
tuent on Ar2 in cases of where Ar1 = 4-n-BuC6H4 (Table 1,
entries 2–9). By increasing the electron withdrawing capability
of Ar2, slightly decreased yields (61% and 63%) were observed
for 2f and 2g, respectively. In case of where Ar2 = 4-PhC6H4, 2h
was isolated in 53% yield. A steric hindrance was observed
when Ar2 = 3-CH3OC6H4 in comparison with the case where
Ar2 = 4-CH3OC6H4. In cases where Ar1 = phenyl, only four pro-
ducts (2a, 2j, 2k, and 2l) were successfully obtained in yields of
82%, 52%, 75%, and 76%, respectively, due to the solubility
problem.
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Scheme 3 One-pot formation of 3o and 3p from 1o and 1p.
Scheme 5 Formation of 4c, 4d, 5c, and 5d.
Table 2 The photophysical properties of heptaaryldipyrromethenes
and BODIPYsa
b
Entry λabs/nm Entry λabs/nm λem/nm Stokes shift/nm ΦF
2a
2b
2c
2d
2e
2f
2g
2h
2i
2j
2k
2l
2m
2n
4a
4b
4c
4d
542
540
560
560
564
565
559
564
558
547
540
542
555
550
563
564
580
564
3a
3b
3c
3d
3e
3f
3g
3h
3i
3j
3k
3l
3m
3n
5a
5b
5c
5d
570
582
581
579
591
596
588
586
580
568
571
568
577
572
586
587
590
585
604
626
619
618
635
640
627
627
620
600
605
601
614
606
624
625
632
625
34
44
38
39
44
44
39
41
40
32
34
33
37
34
38
38
42
40
0.30
0.15
0.21
0.22
0.26
0.17
0.2
0.26
0.21
0.11
0.07
0.18
0.21
0.02
0.23
0.25
0.15
0.11
Scheme 4 Formation of 4a, 4b, 5a, and 5b.
The dipyrromethene core tolerated the reaction conditions of
Suzuki coupling and Sonogashira couplings. Structures of 4 and
5 were confirmed by 1H NMR and 13C NMR spectroscopy
(Fig. S79–S90†) and HRMS.
a Samples were dissolved in freshly distilled DCM and diluted to
1 × 10−5 mol L−1 for absorption and emission measurement. b The
relative quantum yield is measured based on Rhodamine 6 G as external
standard (Φ = 0.95 in ethanol).19
Heptaaryldipyrromethenes are yellowish solids with melting
points above 150 °C, while heptaaryl BODIPYs are reddish-
brown solids with melting points above 160 °C. The UV-vis
absorption and photoluminescence of these synthesized com-
pounds in dilute methylene chloride solutions are summarised in
Table 2 (Full version including the absorptive molar coefficiency
is included in Table S2 in ESI†). For heptaaryldipyrromethenes
(2a–2n, 4a–4d), their maximum absorption wavelengths varied
from 540 nm to 580 nm, while the emissions were too weak to
be detected. For BODIPYs (3a–3n, 5a–5d), the maximum
absorption wavelengths were red-shifted 20–30 nm with respect
to the corresponding 2a–2n, 4a–4d. In comparison with the
smallest, naked BODIPY which emits light at 526 nm with a
quantum yield of 0.76 in chloroform,19 emissions of heptaaryl
BODIPYs are all red-shifted through extended conjugation and
present lower quantum yields. Thus, the maximum emission
wavelengths of heptaaryl BODIPYs ranged from 600 nm to
640 nm with 32–44 nm Stokes shifts. Quantum yields of these
BODIPYs were determined to be 0.02–0.3 by using Rhodamine
6G as standard.20
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Fig. 1 IUPAC numbering of dipyrromethene and BODIPY.
Fig. 3 Normalized absorption spectra of 2a, 2k, 2l, 4d, 3a, 3k, 3l, and
5d in CH2Cl2 solutions (1 × 10−5 mol L−1) (the dotted lines) and nor-
malized fluorescence spectra (the solid lines) of 3a, 3k, 3l, and 5d in
CH2Cl2 solutions (1 × 10−5 mol L−1), excited with maximum absorption
wavelength.
Fig. 2 Normalized absorption spectra of 2a, 2b, 4c, 3a, 3b, and 5c in
CH2Cl2 solutions (1 × 10−5 mol L−1) (the dotted lines) and normalized
fluorescence spectra (the solid lines) of 3a, 3b, and 5c in CH2Cl2 solu-
tions (1
wavelength.
×
10−5 mol L−1), excited with maximum absorption
Alkylation at the phenyls on the 1, 2, 8, and 9 positions of
dipyrromethene (Fig. 1) has no special influence on the absorp-
tion (compare 2a with 2b), while alkynylation at these positions
of dipyrromethene presents red-shifted absorption (compare 2a
with 4c). A similar situation is observed for the corresponding
BODIPYs (3a, 3b, and 5c). 5c absorbs light with the longest
wavelength at 590 nm and emits light with the longest wave-
length at 632 nm. However, the quantum yield of 3a is higher
than alkylated 3b and alkynylated 5c (Fig. 2).
Alkylation or alkoxylation at phenyls on 3, 5, and 7 positions
of dipyrromethene has no special effect on the absorption
(compare 2a, 2k, and 2l), while alkynylation at phenyls on these
positions of dipyrromethene exhibits slightly red-shifted absorp-
tion (compare 2a with 4d). The same is seen for the correspond-
ing BODIPYs (3a, 3k, 3l, and 5d) (Fig. 3). A larger substitute
effect is observed for positions 1, 2, 8, and 9 of dipyrromethene
than for positions 3, 5, and 7 of dipyrromethene. Further, 3a pre-
sents the highest quantum yield among these alkylated, alkoxy-
lated, and alkynylated compounds.
No apparent substituent effect of phenyls on the 3, 5, and 7
positions of dipyrromethene on absorption is observed (2c–2h).
They absorb light between 559 nm and 564 nm. However, for
their corresponding BODIPYs, red-shifted absorption and emis-
sion are observed for those with electron–withdrawing groups
(3e, 3f, and 3g) in comparison with those with electron-donating
groups (3a and 3d) (Fig. 4). Thus, trifluoromethylated 3f absorbs
light at 596 nm and emits light at 640 nm, while methylated 3d
absorbs light at 579 nm and emits light at 618 nm.
Fig. 4 Normalized absorption spectra of 3a, 3d, 3e, 3f, and 3g in
CH2Cl2 solutions (1 × 10−5 mol L−1) (the dotted lines) and normalized
fluorescence spectra (the solid lines) of 3a, 3d, 3e, 3f, and 3g in CH2Cl2
solutions (1 × 10−5 mol L−1), excited with maximum absorption
wavelength.
electrons of the pyrrole nitrogen. The titration of 2b with H+ is
then investigated (Fig. 5). As the Fig. 5 shows, the absorption of
2b at 557 nm gradually diminishes as two new peaks at 432 nm
and 636 nm appeared with increasing concentration of H+.
Accordingly, three isosbestic points, 388 nm, 468 nm and
588 nm, are clearly observed. Similar phenomena were observed
for other heptaaryldipyrromethenes 2c–2i and 2l (Fig. S91–
S98†).
Conclusions
In conclusion, we have demonstrated a convenient method for
the preparation of heptaaryldipyrromethenes from cyclopenta-
dienones and ammonium acetate. The transformation involves a
one-pot cascade process and can be run under mild conditions
with moderate to good yields. The synthesized heptaaryldipyrro-
methenes could be converted into the corresponding heptaaryl
As expected, heptaaryldipyrromethenes (2a–2n) show pH-
sensitive behaviour which could be ascribed to the lone pair
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The resulting mixture was stirred at reflux for 1 h. The mixture
was then cooled to 0 °C, and the resulting precipitate was col-
lected by filtration or by flash chromatography (silica, CH2Cl2–
hexane). In this way, 2,3,4,5-tetraphenylcyclopenta-2,4-dienone
derivatives were obtained.
3,4-Bis(4-butylphenyl)-2,5-diphenylcyclopenta-2,4-dienone (1b).
Yield 87%. Brown solid. m.p. 117–118 °C. 1H NMR (400 MHz,
CDCl3) δ 7.33–7.16 (m, 5H), 6.99 (d, J = 8.1 Hz, 2H), 6.84 (d,
J = 8.1 Hz, 2H), 2.64–2.55 (m, 2H), 1.59 (dt, J = 15.3, 7.6 Hz,
2H), 1.40–1.29 (m, 2H), 0.95 (t, J = 7.3 Hz, 3H). 13C NMR
(100 MHz, CDCl3) δ 200.7, 155.0, 143.7, 131.4, 130.6, 130.4,
129.9, 129.6, 128.7, 128.2, 128.1, 127.5, 125.1, 35.7, 33.5,
22.5, 14.3. HRMS (EI) calcd for C37H36O 496.2766 (M+),
found 496.2776.
3,4-Bis(4-butylphenyl)-2,5-bis(4-methoxyphenyl)cyclopenta-
2,4-dienone (1c). Yield 83%. Black solid. m.p. 204–205 °C.
1H NMR (400 MHz, CDCl3) δ 7.22 (d, J = 8.8 Hz, 2H), 6.99 (d,
J = 8.1 Hz, 2H), 6.84 (d, J = 8.1 Hz, 2H), 6.80 (d, J = 8.8 Hz,
2H), 3.80 (s, 3H), 2.59 (t, J = 7.7 Hz, 2H), 1.60 (tt, J = 15.3,
7.6 Hz, 2H), 1.33 (dt, J = 14.6, 7.4 Hz, 2H), 0.95 (t, J = 7.3 Hz,
3H). 13C NMR (100 MHz, CDCl3) δ 200.7, 163.7, 161.2, 155.0,
144.0, 132.2, 132.1, 130.4, 129.6, 128.4, 127.4, 127.3, 124.2,
115.5, 115.3, 35.7, 33.5, 22.5, 14.2. HRMS (EI) calcd for
C39H40O3 556.2977 (M+), found 556.2983.
Fig. 5 Absorption spectra of 2b (the black line) and its response to
increased H+ (the colored lines) in dilute THF solution (10−5 M).
BODIPYs in excellent yields. Moreover, the heptaaryldipyrro-
methenes exhibited pH sensitive absorption spectra and might be
used as pH chemosensors, while the heptaaryl BODIPYs
emitted intense light in a range of 600 nm and 640 nm and
might be applied as red emitters in optoelectronics.
3,4-Bis(4-butylphenyl)-2,5-di-p-tolylcyclopenta-2,4-dienone (1d).
Yield 88%. Black solid. m.p. 175–176 °C. H NMR (400 MHz,
Experimental
1
CDCl3) δ 7.18 (d, J = 8.0 Hz, 2H), 7.07 (d, J = 8.3 Hz, 2H),
7.00 (d, J = 8.0 Hz, 2H), 6.85 (d, J = 7.9 Hz, 2H), 2.60 (t, J =
7.7 Hz, 2H), 2.34 (s, 3H), 1.59 (dd, J = 15.2, 7.8 Hz, 2H), 1.36
(dd, J = 14.8, 7.4 Hz, 2H), 0.96 (t, J = 7.3 Hz, 3H). 13C NMR
(100 MHz, CDCl3) δ 201.2, 154.4, 143.5, 137.3, 130.9, 130.3,
129.6, 129.0, 128.5, 128.1, 124.9, 35.7, 33.5, 22.5, 21.6, 14.2.
HRMS (EI) calcd for C39H40O 524.3079 (M+), found 524.3084.
General methods and materials
Thin layer chromatography (TLC) was performed on silica F254
plates and observed by UV light. Flash column chromatography
was performed employing 200–300 mesh silica gel. NMR
1
spectra were recorded on 400 MHz or 500 MHz for H NMR
and at 100 MHz or 125 MHz for 13C NMR in CDCl3. Chemical
shifts are reported in ppm with either TMS or residual solvent as
an internal standard. NMR spectra were edited by MestreNova
(Version: 7.1.1–9649). High-resolution mass spectra (HRMS)
were recorded by EI or ESI method. Melting points were
obtained using a heating rate of 5 °C min−1. UV-vis absorption
and fluorescence spectra were recorded in dichloromethane
(DCM) solvent with a concentration of 1 × 10−5 M.
2,5-Bis(4-bromophenyl)-3,4-bis(4-butylphenyl)cyclopenta-2,4-
dienone (1e). Yield 85%. Black solid. m.p. 198–199 °C. 1H
NMR (400 MHz, CDCl3) δ 7.38 (d, J = 8.5 Hz, 2H), 7.19–7.08
(m, 2H), 7.01 (d, J = 8.1 Hz, 2H), 6.80 (d, J = 8.1 Hz, 2H),
2.68–2.50 (m, 2H), 1.66–1.51 (m, 2H), 1.42–1.27 (m, 2H), 0.95
(t, J = 7.3 Hz, 3H). 13C NMR (100 MHz, CDCl3) δ 199.9,
155.5, 144.2, 131.9, 131.5, 130.1, 129.5, 128.4, 124.2, 122.0,
35.8, 33.5, 22.5, 14.2. HRMS (EI) calcd for C37H34Br2O
652.0976 (M+), found 652.0986.
Unless otherwise stated, phenylacetic acids and benzils were
purchased from commercial suppliers and used without further
purification. 1,3-Bis(4-methoxyphenyl)propan-2-one,21 1,3-bis-
(3-methoxyphenyl)propan-2-one,21 1,3-bis(4-(trifluoromethyl)-
phenyl)propan-2-one,21 1,3-bis(4-fluorophenyl)propan-2-one,21
3,4-Bis(4-butylphenyl)-2,5-bis(4-(trifluoromethyl)phenyl)cyclo-
penta-2,4-dienone (1f). Yield 79%. Brown solid. m.p.
200–201 °C. 1H NMR (400 MHz, CDCl3) δ 7.50 (d, J = 8.4 Hz,
2H), 7.36 (d, J = 8.2 Hz, 2H), 7.01 (d, J = 8.1 Hz, 2H), 6.80 (d,
J = 8.1 Hz, 2H), 2.63–2.55 (m, 2H), 1.59 (t, J = 7.7 Hz, 2H),
1.33 (dd, J = 14.9, 7.4 Hz, 2H), 0.93 (t, J = 7.3 Hz, 3H). 13C
NMR (100 MHz, CDCl3) δ 199.4, 156.8, 144.6, 134.8, 130.6,
129.7, 129.6, 129.5, 129.3, 128.5, 125.8, 125.2, 125.1, 124.3,
123.1, 35.8, 33.5, 22.6, 14.2. HRMS (EI) calcd for C39H34F6O
632.2514 (M+), found 632.2516.
1,3-di-p-tolylpropan-2-one,22
1,3-bis(4-bromophenyl)propan-
2-one,22 1,3-di([1,1′-biphenyl]-4-yl)propan-2-one,23 and 1,3-bis-
(4-(tert-butyl)phenyl)propan-2-one24 were synthesized according
to published procedures. Tetrahydrofuran (THF) and toluene
were distilled from sodium–benzophenone. DCM was distilled
from calcium hydride (CaH2). Yields were isolated yields.
General procedure for the synthesis of 125
A solution of KOH (0.28 g, 5.0 mmol) in ethanol (5 mL)
was added to a mixture of benzil derivative (10.0 mmol) and
1,3-diphenylacetone derivative (10.0 mmol) in ethanol (50 mL).
3,4-Bis(4-butylphenyl)-2,5-bis(4-fluorophenyl)cyclopenta-2,4-
dienone (1g). Yield 82%. Brown solid. m.p. 131–132 °C. 1H
NMR (400 MHz, CDCl3) δ 7.22 (dd, J = 8.5, 5.7 Hz, 2H),
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7.02–6.89 (m, 4H), 6.79 (d, J = 8.0 Hz, 2H), 2.62–2.54 (m, 2H),
1.61–1.53 (m, 2H), 1.32 (dd, J = 14.9, 7.4 Hz, 2H), 0.93 (t, J =
7.3 Hz, 3H). 13C NMR (100 MHz, CDCl3) δ 200.7, 163.6,
161.2, 155.0, 144.0, 132.2, 132.1, 130.3, 129.6, 128.3, 127.3,
127.2, 124.1, 115.5, 115.3, 35.7, 33.5, 22.5, 14.2. HRMS (EI)
calcd for C37H34F2O 532.2578 (M+), found 532.2583.
124.4, 123.6, 114.3, 67.7, 31.5, 21.7, 19.5, 14.1. HRMS (EI)
calcd for C39H40O3 556.2977 (M+), found 556.2982.
3,4-Bis(4-bromophenyl)-2,5-bis(4-butoxyphenyl)cyclopenta-
2,4-dienone (1n). Yield 73%. Brown solid. m.p. 189–190 °C.
1H NMR (400 MHz, CDCl3) δ 7.33 (d, J = 8.3 Hz, 4H), 7.13 (d,
J = 8.6 Hz, 4H), 6.78 (t, J = 8.0 Hz, 8H), 3.93 (t, J = 6.5 Hz,
4H), 1.80–1.70 (m, 4H), 1.47 (dd, J = 15.0, 7.4 Hz, 4H), 0.96
(t, J = 7.4 Hz, 6H). 13C NMR (100 MHz, CDCl3) δ 201.0,
159.1, 151.2, 132.8, 132.4, 131.7, 131.6, 131.3, 125.3, 123.0,
122.7, 114.5, 67.8, 31.5, 19.5, 14.1. HRMS (EI) calcd for
C37H34Br2O3 684.0875 (M+), found 684.0868.
2,5-Di([1,1′-biphenyl]-4-yl)-3,4-bis(4-butylphenyl)cyclopenta-
2,4-dienone (1h). Yield 78%. Brown solid. m.p. 168–169 °C.
1H NMR (400 MHz, CDCl3) δ 7.62 (d, J = 7.4 Hz, 2H), 7.52 (d,
J = 8.3 Hz, 2H), 7.48–7.38 (m, 4H), 7.35 (t, J = 7.3 Hz, 2H),
7.03 (d, J = 8.1 Hz, 2H), 6.91 (d, J = 8.1 Hz, 2H), 2.66–2.57
(m, 2H), 1.62 (t, J = 7.6 Hz, 2H), 1.37 (dd, J = 14.9, 7.4 Hz,
2H), 0.97 (t, J = 7.3 Hz, 3H). 13C NMR (100 MHz, CDCl3)
δ 200.9, 155.2, 143.8, 141.0, 140.1, 130.7, 130.4, 129.6, 129.0,
128.3, 127.5, 127.2, 126.9, 124.7, 35.7, 33.5, 22.6, 14.3. HRMS
(EI) calcd for C49H44O 648.3392 (M+), found 648.3393.
3,4-Bis(4-bromophenyl)-2,5-diphenylcyclopenta-2,4-dienone (1o).
Yield 90%. Black solid. m.p. 249–250 °C (246.8–246.9 °C).26
1H NMR (400 MHz, CDCl3) δ 7.34 (d, J = 8.4 Hz, 2H), 7.26 (d,
J = 5.6 Hz, 3H), 7.23–7.17 (m, 2H), 6.80 (d, J = 8.4 Hz, 2H).
13C NMR (100 MHz, CDCl3) δ 199.8, 152.8, 131.8, 131.7,
131.2, 130.4, 130.3, 128.5, 128.1, 126.1, 123.4. HRMS (EI)
calcd for C29H18Br2O 539.9724 (M+), found 539.9731.
3,4-Bis(4-butylphenyl)-2,5-bis(3-methoxyphenyl)cyclopenta-
2,4-dienone (1i). Yield 81%. Dark purple solid. m.p.
1
201–202 °C. H NMR (400 MHz, CDCl3) δ 7.18 (t, J = 7.9 Hz,
2,5-Bis(4-bromophenyl)-3,4-diphenylcyclopenta-2,4-dienone
(1p). Yield 91%. Black solid. m.p. >300 °C (302–303 °C).27
1H NMR (400 MHz, CDCl3) δ 7.37 (t, J = 8.7 Hz, 1H), 7.21
(t, J = 7.6 Hz, 1H), 7.12 (d, J = 8.4 Hz, 1H), 6.92 (d, J = 7.4 Hz,
1H), 6.81 (d, J = 8.3 Hz, 1H). 13C NMR (100 MHz, CDCl3)
δ 199.9, 155.2, 132.7, 131.9, 131.6, 131.2, 130.3, 129.4, 128.4,
124.6, 122.2. HRMS (EI) calcd for C29H18Br2O 539.9724 (M+),
found 539.9736.
1H), 7.02 (d, J = 8.1 Hz, 2H), 6.90 (dd, J = 15.1, 7.9 Hz, 3H),
6.81 (dd, J = 11.5, 1.8 Hz, 2H), 3.63 (s, 3H), 2.60 (t, J = 7.7 Hz,
2H), 1.67–1.54 (m, 2H), 1.35 (dd, J = 14.9, 7.4 Hz, 2H), 0.96
(t, J = 7.3 Hz, 3H). 13C NMR (100 MHz, CDCl3) δ 200.4,
159.3, 155.2, 143.7, 132.5, 130.6, 129.6, 129.2, 128.2, 125.0,
122.9, 114.9, 114.3, 55.1, 35.7, 33.5, 22.5, 14.2. HRMS (EI)
calcd for C39H40O3 556.2977 (M+), found 556.2986.
2,5-Bis(4-butoxyphenyl)-3,4-diphenylcyclopenta-2,4-dienone
(1j). Yield 79%. Black solid. m.p. 144–145 °C. 1H NMR
(400 MHz, CDCl3) δ 7.22 (dt, J = 24.7, 7.2 Hz, 10H), 6.96 (d,
J = 7.5 Hz, 4H), 6.79 (d, J = 8.6 Hz, 4H), 3.95 (t, J = 6.4 Hz,
4H), 1.83–1.72 (m, 4H), 1.50 (dd, J = 14.9, 7.4 Hz, 4H), 0.99
(t, J = 7.4 Hz, 6H). 13C NMR (100 MHz, CDCl3) δ 201.7,
158.8, 153.2, 133.8, 131.8, 131.6, 129.6, 128.5, 128.2, 124.7,
123.3, 114.3, 114.2, 67.8, 31.5, 19.5, 14.1. HRMS (EI) calcd for
C37H36O3 528.2664 (M+), found 528.2663.
General procedure for the synthesis of 2
2,3,4,5-Tetraphenylcyclopenta-2,4-dienone derivative (1 mmol)
and NH4OAc (20 mmol) were mixed in a 15 ml sealed tube
reactor, HOAc (2 mL) was added and sealed. The mixture was
heated to reflux for 20 h. After the mixture was cooled to room
temperature, water (100 mL) was added. The mixture was
extracted with CH2Cl2 (50 mL × 3), the organic layer was dried
over MgSO4 and the solvent was removed on a rotary evaporator
under vacuum. The crude product was purified by silica gel
column chromatography with hexane–CH2Cl2 (30 : 70) as eluent
to afford heptaaryldipyrromethenes (2) in good yields.
2,5-Bis(4-(tert-butyl)phenyl)-3,4-diphenylcyclopenta-2,4-dienone
(1k). Yield 82%. Brown solid. m.p. 263–264 °C. 1H NMR
(400 MHz, CDCl3) δ 7.31–7.16 (m, 7H), 6.98 (s, 2H), 1.31 (s,
9H). 13C NMR (100 MHz, CDCl3) δ 201.3, 154.2, 150.5, 133.7,
130.0, 129.6, 128.6, 128.2, 128.0, 125.3, 125.1, 34.8, 31.5.
HRMS (EI) calcd for C37H36O 496.2766 (M+), found 496.2772.
(Z)-2,3,4-Triphenyl-5-(phenyl(3,4,5-triphenyl-2H-pyrrol-2-
ylidene)methyl)-1H-pyrrole (2a). Yield 82%. Reddish-brown
1
solid. m.p. >300 °C. H NMR (400 MHz, CDCl3) δ 8.00 (s,
2,5-Bis(3-methoxyphenyl)-3,4-diphenylcyclopenta-2,4-dienone
(1l). Yield 85%. Brown solid. m.p. 198–199 °C. 1H NMR
(400 MHz, CDCl3) δ 7.30–7.17 (m, 5H), 6.98 (d, J = 7.2 Hz,
2H), 6.81 (d, J = 8.8 Hz, 2H), 3.80 (s, 3H). 13C NMR
(100 MHz, CDCl3) δ 201.6, 159.1, 153.3, 133.7, 131.6, 129.5,
128.5, 128.2, 124.6, 123.5, 113.8, 55.4. HRMS (EI) calcd for
C31H24O3 444.1725 (M+), found 444.1722.
2H), 7.98 (s, 2H), 7.56 (s, 4H), 7.54 (s, 4H), 7.45 (t, J = 7.3 Hz,
4H), 7.41 (d, J = 7.1 Hz, 4H), 7.37–7.29 (m, 15H). HRMS (EI)
calcd for C51H35N2 676.2878 (M+), found 676.2875.
(Z)-2-((4,5-Bis(4-butylphenyl)-3-phenyl-2H-pyrrol-2-ylidene)-
(phenyl)methyl)-4,5-bis(4-butylphenyl)-3-phenyl-1H-pyrrole
(2b). Yield 73%. Reddish-brown solid. m.p. 155–156 °C.
1H NMR (400 MHz, CDCl3) δ 15.15 (s, 1H), 7.45 (d, J =
8.1 Hz, 4H), 7.09 (d, J = 8.1 Hz, 4H), 6.91 (d, J = 8.0 Hz, 4H),
6.84 (dd, J = 13.8, 7.9 Hz, 6H), 6.71–6.65 (m, 2H), 6.62 (t, J =
7.2 Hz, 4H), 6.53 (d, J = 7.1 Hz, 4H), 6.48 (d, J = 7.5 Hz, 1H),
6.33 (t, J = 7.5 Hz, 2H), 2.64 (t, J = 7.7 Hz, 4H), 2.57–2.45 (m,
4H), 1.64 (dt, J = 15.3, 7.6 Hz, 4H), 1.54 (dt, J = 15.2, 7.5 Hz,
4H), 1.41 (dt, J = 14.7, 7.3 Hz, 4H), 1.35–1.24 (m, 4H), 0.96 (t,
J = 7.3 Hz, 6H), 0.90 (t, J = 7.3 Hz, 6H). 13C NMR (100 MHz,
2,5-Bis(4-butoxyphenyl)-3,4-di-p-tolylcyclopenta-2,4-dienone
(1m). Yield 77%. Black solid. m.p. 165–166 °C. 1H NMR
(400 MHz, CDCl3) δ 7.25–7.16 (m, 2H), 7.01 (d, J = 8.0 Hz,
2H), 6.86 (d, J = 8.1 Hz, 2H), 6.83–6.76 (m, 2H), 3.96 (t, J =
6.5 Hz, 2H), 2.34 (s, 3H), 1.83–1.72 (m, 2H), 1.51 (dd, J = 15.0,
7.4 Hz, 2H), 1.00 (t, J = 7.4 Hz, 3H). 13C NMR (100 MHz,
CDCl3) δ 201.7, 158.6, 153.3, 138.3, 131.6, 130.7, 129.6, 128.9,
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CDCl3) δ 143.4, 143.3, 142.8, 141.0, 138.3, 136.2, 133.8, 132.7,
132.5, 131.4, 130.8, 130.6, 130.0, 129.5, 128.6, 128.5, 128.0,
126.8, 126.3, 125.0, 110.3, 35.8, 35.6, 33.7, 33.6, 22.7, 22.6,
14.3. HRMS (EI) calcd for C67H68N2 900.5283 (M+), found
900.5390.
(400 MHz, CDCl3) δ 15.13 (s, 1H), 7.46 (d, J = 7.9 Hz, 4H),
7.15 (d, J = 7.9 Hz, 4H), 6.92 (dd, J = 13.9, 7.8 Hz, 10H), 6.84
(d, J = 7.7 Hz, 4H), 6.62 (d, J = 7.4 Hz, 6H), 2.67 (t, J = 7.6 Hz,
4H), 2.54 (t, J = 7.6 Hz, 4H), 1.65 (d, J = 7.3 Hz, 4H), 1.56 (dd,
J = 14.8, 6.8 Hz, 4H), 1.42 (d, J = 7.4 Hz, 4H), 1.32 (d, J =
7.4 Hz, 4H), 0.98 (t, J = 7.3 Hz, 6H), 0.90 (t, J = 7.3 Hz, 6H).
13C NMR (125 MHz, CDCl3) δ 151.6, 144.2, 141.7, 141.3,
139.8, 139.3, 138.1, 133.1, 132.6, 131.6, 130.8, 130.6, 128.8,
128.6, 128.3, 127.8, 123.9, 123.3, 35.8, 35.6, 33.7, 33.5, 22.7,
22.6, 14.3, 14.2. HRMS (ESI) calcd for C70H66F9N2 1105.5082
(M + H), found 1105.5062.
(Z)-2-((4,5-Bis(4-butylphenyl)-3-(4-methoxyphenyl)-2H-pyrrol-
2-ylidene)(4-methoxyphenyl)methyl)-4,5-bis(4-butylphenyl)-3-
(4-methoxyphenyl)-1H-pyrrole (2c). Yield 70%. Reddish-brown
solid. m.p. 148–150 °C. 1H NMR (400 MHz, CDCl3) δ 15.08 (s,
1H), 7.46 (d, J = 7.7 Hz, 4H), 7.11 (d, J = 7.9 Hz, 4H), 6.92 (q,
J = 8.0 Hz, 8H), 6.62 (t, J = 7.8 Hz, 2H), 6.53 (d, J = 7.0 Hz,
1H), 6.43 (s, 1H), 6.36 (t, J = 7.5 Hz, 1H), 6.29 (dd, J = 8.3,
2.3 Hz, 2H), 6.23 (d, J = 7.3 Hz, 2H), 6.18–6.07 (m, 3H), 3.47
(s, 9H), 2.65 (t, J = 7.7 Hz, 4H), 2.53 (t, J = 7.7 Hz, 4H), 1.65
(dd, J = 15.2, 7.9 Hz, 4H), 1.54 (dd, J = 15.1, 7.9 Hz, 4H), 1.41
(dd, J = 14.8, 7.4 Hz, 4H), 1.30 (dt, J = 10.9, 5.5 Hz, 4H), 0.97
(t, J = 7.3 Hz, 6H), 0.91 (t, J = 7.3 Hz, 6H). 13C NMR
(125 MHz, CDCl3) δ 158.0, 157.5, 150.8, 143.5, 143.0, 142.2,
141.1, 138.2, 137.5, 135.3, 132.7, 132.2, 131.4, 130.7, 128.6,
128.5, 128.0, 127.7, 127.5, 125.4, 123.3, 117.8, 115.6, 114.0,
111.9, 54.9, 54.8, 35.8, 35.6, 33.7, 22.7, 22.6, 14.3, 14.2.
HRMS (ESI) calcd for C70H75N2O3 991.5778 (M + H), found
991.5787.
(Z)-2-((4,5-Bis(4-butylphenyl)-3-(4-fluorophenyl)-2H-pyrrol-
2-ylidene)(4-fluorophenyl)methyl)-4,5-bis(4-butylphenyl)-3-(4-
fluorophenyl)-1H-pyrrole (2g). Yield 63%. Reddish-brown
1
solid. m.p. 250–251 °C. H NMR (400 MHz, CDCl3) δ 15.03
(s, 1H), 7.45 (d, J = 7.9 Hz, 4H), 7.12 (d, J = 7.9 Hz, 4H), 6.95
(d, J = 7.8 Hz, 4H), 6.86 (d, J = 7.7 Hz, 4H), 6.81–6.73 (m,
2H), 6.53–6.46 (m, 4H), 6.41 (t, J = 8.6 Hz, 4H), 6.15 (t, J =
8.5 Hz, 2H), 2.66 (t, J = 7.7 Hz, 4H), 2.58–2.51 (m, 4H), 1.64
(dd, J = 15.2, 7.8 Hz, 4H), 1.56 (dt, J = 15.2, 7.6 Hz, 4H), 1.41
(dd, J = 14.8, 7.3 Hz, 4H), 1.35–1.29 (m, 4H), 0.97 (t, J =
7.3 Hz, 6H), 0.92 (t, J = 7.3 Hz, 6H). 13C NMR (125 MHz,
CDCl3) δ 163.7, 161.9, 161.7, 160.0, 151.1, 143.7, 141.9, 141.4,
140.6, 138.5, 134.2, 134.1, 132.7, 132.3, 132.1, 132.0, 131.1,
130.7, 128.7, 128.5, 128.2, 114.9, 114.7, 114.0, 113.8, 113.5,
113.4, 35.8, 35.6, 33.7, 22.7, 14.3. HRMS (ESI) calcd for
C67H66F3N2 955.5178 (M + H), found 955.5192.
(Z)-2-((4,5-Bis(4-butylphenyl)-3-(p-tolyl)-2H-pyrrol-2-ylidene)-
(p-tolyl)methyl)-4,5-bis(4-butylphenyl)-3-(p-tolyl)-1H-pyrrole (2d).
1
Yield 74%. Reddish-brown solid. m.p. 148–150 °C. H NMR
(400 MHz, CDCl3) δ 15.09 (s, 1H), 7.39 (d, J = 8.0 Hz, 4H),
7.04 (d, J = 8.1 Hz, 4H), 6.87 (q, J = 8.1 Hz, 8H), 6.56 (d, J =
7.4 Hz, 2H), 6.36 (q, J = 8.0 Hz, 8H), 6.07 (d, J = 7.5 Hz, 2H),
2.59 (t, J = 7.7 Hz, 4H), 2.52–2.43 (m, 4H), 2.02 (s, 6H), 1.90
(s, 3H), 1.65–1.56 (m, 4H), 1.55–1.45 (m, 4H), 1.36 (dd, J =
14.9, 7.4 Hz, 4H), 1.27 (dd, J = 14.8, 7.4 Hz, 4H), 0.92 (t, J =
7.3 Hz, 6H), 0.86 (t, J = 7.3 Hz, 6H). 13C NMR (100 MHz,
CDCl3) δ 150.6, 143.4, 143.3, 143.2, 143.1, 140.9, 138.6, 137.3,
134.2, 133.2, 133.0, 132.4, 131.8, 131.6, 130.9, 130.5, 128.5,
128.0, 127.4, 126.8, 35.8, 35.6, 33.7, 33.6, 22.7, 22.6, 21.2,
21.1, 14.3, 14.3. HRMS (ESI) calcd for C70H75N2 943.5930
(M + H), found 943.5905.
(Z)-3-([1,1′-Biphenyl]-4-yl)-2-([1,1′-biphenyl]-4-yl(3-([1,1′-
biphenyl]-4-yl)-4,5-bis(4-butylphenyl)-2H-pyrrol-2-ylidene)methyl)-
4,5-bis(4-butylphenyl)-1H-pyrrole (2h). Yield 53%. Purple solid.
m.p. >300 °C. 1H NMR (400 MHz, CDCl3) δ 7.47 (d, J =
7.7 Hz, 4H), 7.19 (s, 11H), 7.11 (d, J = 7.6 Hz, 6H), 6.98–6.80
(m, 16H), 6.62 (d, J = 7.6 Hz, 6H), 6.53 (d, J = 7.9 Hz, 2H),
2.65 (d, J = 7.9 Hz, 4H), 2.58–2.48 (m, 4H), 1.65 (m, 4H), 1.56
(m, 4H), 1.42 (m, 4H), 1.35–1.23 (m, 4H), 0.98 (t, J = 7.3 Hz,
6H), 0.90 (t, J = 7.3 Hz, 6H). 13C NMR (125 MHz, CDCl3) δ
143.4, 142.7, 141.0, 131.0, 130.8, 128.5, 128.2, 128.0, 127.5,
127.1, 126.8, 125.4, 35.7, 35.5, 33.6, 33.5, 22.6, 22.5, 14.2,
14.1. HRMS (ESI) calcd for C85H81N2 1129.6400 (M + H),
found 1129.6405.
(Z)-3-(4-Bromophenyl)-2-((4-bromophenyl)(3-(4-bromophenyl)-
4,5-bis(4-butylphenyl)-2H-pyrrol-2-ylidene)methyl)-4,5-bis(4-
butylphenyl)-1H-pyrrole (2e). Yield 71%. Reddish-brown solid.
(Z)-2-((4,5-Bis(4-butylphenyl)-3-(3-methoxyphenyl)-2H-pyrrol-
2-ylidene)(3-methoxyphenyl)methyl)-4,5-bis(4-butylphenyl)-3-(3-
methoxyphenyl)-1H-pyrrole (2i). Yield 68%. Reddish-brown
solid. m.p. 139–140 °C. 1H NMR (400 MHz, CDCl3) δ 15.04 (s,
1H), 7.45 (d, J = 7.8 Hz, 4H), 7.10 (d, J = 8.0 Hz, 4H), 6.93
(dd, J = 16.9, 7.9 Hz, 8H), 6.69 (d, J = 7.7 Hz, 2H), 6.45 (d, J =
8.2 Hz, 4H), 6.22 (d, J = 8.2 Hz, 4H), 5.92 (d, J = 7.9 Hz, 2H),
3.59 (s, 6H), 3.51 (s, 3H), 2.65 (t, J = 7.5 Hz, 4H), 2.59–2.51
(m, 4H), 1.70–1.61 (m, 4H), 1.60–1.51 (m, 4H), 1.42 (d, J = 7.3
Hz, 4H), 1.33 (dd, J = 14.9, 7.4 Hz, 4H), 0.98 (t, J = 7.3 Hz,
6H), 0.93 (t, J = 7.3 Hz, 6H). HRMS (ESI) calcd for
C70H75N2O3 991.5778 (M + H), found 991.5783.
1
m.p. >300 °C. H NMR (400 MHz, CDCl3) δ 15.05 (s, 1H),
7.44 (d, J = 8.1 Hz, 4H), 7.12 (d, J = 8.1 Hz, 4H), 6.96 (d, J =
8.0 Hz, 4H), 6.86 (dd, J = 8.2, 3.3 Hz, 8H), 6.61 (q, J = 8.5 Hz,
4H), 6.39 (d, J = 8.3 Hz, 4H), 2.69–2.61 (m, 4H), 2.60–2.50 (m,
4H), 1.64 (d, J = 7.6 Hz, 4H), 1.60–1.53 (m, 4H), 1.41 (dd, J =
14.9, 7.4 Hz, 4H), 1.31 (dd, J = 16.4, 9.0 Hz, 4H), 0.97 (dt, J =
19.4, 7.3 Hz, 12H). 13C NMR (100 MHz, CDCl3) δ 157.3,
144.0, 142.2, 141.3, 135.2, 133.8, 133.5, 132.2, 132.0, 130.9,
130.6, 130.0, 129.2, 128.9, 127.9, 127.8, 124.2, 120.8, 35.8,
35.5, 33.4, 33.3, 22.6, 22.5, 14.2, 14.1. HRMS (ESI) calcd for
C67H66Br3N2 1135.2776 (M + H), found 1135.2792.
(Z)-2-((4,5-Bis(4-butylphenyl)-3-(4-(trifluoromethyl)phenyl)-
2H-pyrrol-2-ylidene)(4-(trifluoromethyl)phenyl)methyl)-4,5-bis-
(4-butylphenyl)-3-(4-(trifluoromethyl)phenyl)-1H-pyrrole (2f).
(Z)-3-(4-Butoxyphenyl)-2-((4-butoxyphenyl)(3-(4-butoxyphenyl)-
4,5-diphenyl-2H-pyrrol-2-ylidene)methyl)-4,5-diphenyl-1H-pyrrole
(2j). Yield 52%. Reddish-brown solid. m.p. 229–230 °C. 1H
NMR (400 MHz, CDCl3) δ 7.50 (d, J = 6.6 Hz, 4H), 7.30 (s,
1
Yield 61%. Reddish-brown solid. m.p. 290–291 °C. H NMR
8854 | Org. Biomol. Chem., 2012, 10, 8848–8859
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6H), 7.14 (s, 6H), 7.01 (s, 4H), 6.69 (d, J = 7.8 Hz, 2H), 6.44
(d, J = 8.1 Hz, 4H), 6.23 (d, J = 8.0 Hz, 4H), 5.92 (d, J =
7.8 Hz, 2H), 3.71 (t, J = 6.5 Hz, 4H), 3.61 (t, J = 6.5 Hz, 2H),
1.73–1.55 (m, 6H), 1.43 (d, J = 7.0 Hz, 6H), 0.96 (t, J = 8.6 Hz,
9H). 13C NMR (125 MHz, CDCl3) δ 159.0, 156.7, 143.8, 143.7,
138.7, 136.1, 135.7, 134.0, 133.8, 131.6, 131.1, 128.6, 128.5,
128.4, 128.3, 128.1, 127.8, 126.5, 113.3, 112.6, 67.8, 67.7, 31.7,
19.6, 19.5, 14.2. HRMS (ESI) calcd for C63H61N2O3 893.4682
(M + H), found 893.4658.
under N2 for 5 min. A catalytic amount of Pd(PPh3)4 (6 mg,
0.005 mmol) was added and the reaction mixture was refluxed
under N2 at 80 °C for 12 h until TLC indicated the complete dis-
appearance of 2e. Then the mixture was cooled to room tempera-
ture, water (200 mL) was added. The mixture was extracted with
CH2Cl2, the combined organic layer was washed with water and
brine and dried over MgSO4. The solvent was removed on a
rotary evaporator under vacuum. The crude product was purified
by silica gel column chromatography with hexane–dichloro-
methane (30 : 70) as eluent to afford 4a and 4b in 77% and 75%
yields, respectively.
(Z)-3-(4-(tert-Butyl)phenyl)-2-((4-(tert-butyl)phenyl)(3-(4-(tert-
butyl)phenyl)-4,5-diphenyl-2H-pyrrol-2-ylidene)methyl)-4,5-
diphenyl-1H-pyrrole (2k). Yield 75%. Reddish-brown solid.
m.p. >300 °C. 1H NMR (400 MHz, CDCl3) δ 7.50 (d, J =
6.4 Hz, 4H), 7.29 (s, 6H), 7.08 (q, J = 6.4 Hz, 6H), 6.94 (s, 2H),
6.87 (d, J = 6.7 Hz, 4H), 6.71 (d, J = 8.1 Hz, 4H), 6.49 (d, J =
7.6 Hz, 6H), 1.10 (s, 18H), 1.02 (s, 9H). 13C NMR (125 MHz,
CDCl3) δ 163.4, 147.7, 144.5, 135.7, 135.2, 133.1, 133.0, 132.4,
131.1, 130.2, 128.72, 128.67, 128.58, 128.54, 128.42, 128.41,
127.8, 126.4, 126.3, 123.6, 123.1, 34.43, 34.40, 31.6, 31.5.
HRMS (EI) calcd for C63H60N2 844.4756 (M+), found
844.4760.
(Z)-2-((4,5-Bis(4-butylphenyl)-3-(4′-methyl-[1,1′-biphenyl]-4-yl)-
2H-pyrrol-2-ylidene)(4′-methyl-[1,1′-biphenyl]-4-yl)methyl)-4,5-
bis(4-butylphenyl)-3-(4′-methyl-[1,1′-biphenyl]-4-yl)-1H-pyrrole
(4a). Dark purple solid. m.p. >300 °C. 1H NMR (500 MHz,
CDCl3) δ 15.30 (s, 1H), 7.46 (d, J = 7.1 Hz, 4H), 7.09 (d, J =
5.4 Hz, 8H), 6.99 (d, J = 7.2 Hz, 4H), 6.92 (s, 8H), 6.83 (d, J =
7.7 Hz, 6H), 6.73 (s, 4H), 6.58 (d, J = 7.0 Hz, 4H), 6.49 (d, J =
7.7 Hz, 2H), 2.65 (t, J = 6.8 Hz, 4H), 2.55–2.49 (m, 4H), 2.31
(s, 6H), 2.27 (s, 3H), 1.69–1.61 (m, 4H), 1.41 (dd, J = 13.7,
6.6 Hz, 4H), 1.32–1.25 (m, 8H), 0.97 (t, J = 6.7 Hz, 6H),
0.92–0.86 (m, 6H). 13C NMR (125 MHz, CDCl3) δ 150.9,
143.4, 143.0, 142.4, 141.1, 138.5, 138.4, 138.3, 137.6, 136.5,
135.1, 132.9, 132.8, 132.7, 132.2, 131.4, 131.1, 131.0, 130.9,
129.3, 129.0, 128.6, 128.2, 128.1, 127.4, 127.0, 125.3, 125.0,
114.0, 113.7, 35.8, 35.6, 33.7, 33.6, 23.0, 22.7, 22.6, 21.3, 14.3,
14.2. HRMS (ESI) calcd for C88H87N2 1171.6869 (M + H),
found 1171.6896.
(Z)-3-(3-Methoxyphenyl)-2-((3-methoxyphenyl)(3-(3-methoxy-
phenyl)-4,5-diphenyl-2H-pyrrol-2-ylidene)methyl)-4,5-diphenyl-
1H-pyrrole (2l). Yield 76%. Reddish-brown solid. m.p.
1
>300 °C. H NMR (400 MHz, CDCl3) δ 15.00 (s, 1H), 7.49 (d,
J = 6.5 Hz, 5H), 7.29 (s, 5H), 7.13 (s, 6H), 6.99 (s, 4H), 6.68 (d,
J = 8.1 Hz, 2H), 6.44 (d, J = 8.4 Hz, 4H), 6.22 (d, J = 8.3 Hz,
4H), 5.92 (d, J = 7.9 Hz, 2H), 3.59 (s, 6H), 3.51 (s, 3H).
HRMS (ESI) calcd for C54H43N2O3 767.3274 (M + H), found
767.3255.
(Z)-2-((4,5-Bis(4-butylphenyl)-3-(4′-methoxy-[1,1′-biphenyl]-4-yl)-
2H-pyrrol-2-ylidene)(4′-methoxy-[1,1′-biphenyl]-4-yl)methyl)-
4,5-bis(4-butylphenyl)-3-(4′-methoxy-[1,1′-biphenyl]-4-yl)-1H-
pyrrole (4b). Purple solid. m.p. 293–294 °C. 1H NMR
(400 MHz, CDCl3) δ 15.10 (s, 1H) 7.47 (d, J = 8.1 Hz, 4H),
7.41–7.36 (m, 6H), 7.16–7.09 (m, 6H), 6.94 (d, J = 4.0 Hz, 8H),
6.91–6.86 (m, 8H), 6.69 (d, J = 7.9 Hz, 2H), 6.56 (d, J =
7.9 Hz, 4H), 6.50 (d, J = 7.8 Hz, 2H), 3.83 (s, 9H), 2.69–2.63
(m, 4H), 2.57–2.52 (m, 4H), 1.69–1.63 (m, 4H), 1.59–1.53 (m,
4H), 1.45–1.40 (m, 4H), 1.37–1.31 (m, 4H), 0.94–0.89 (m,
12H). HRMS (ESI) calcd for C88H87N2O3 1219.6717 (M + H),
1219.6696.
(Z)-3-(4-Butoxyphenyl)-2-((4-butoxyphenyl)(3-(4-butoxyphenyl)-
4,5-di-p-tolyl-2H-pyrrol-2-ylidene)methyl)-4,5-di-p-tolyl-1H-pyrrole
(2m). Yield 71%. Reddish-brown solid. m.p. 280–281 °C. 1H
NMR (500 MHz, CDCl3) δ 14.94 (s, 1H), 7.41 (d, J = 7.8 Hz,
4H), 7.09 (d, J = 7.9 Hz, 4H), 6.92 (d, J = 7.8 Hz, 4H), 6.86
(d, J = 7.9 Hz, 4H), 6.64 (d, J = 7.5 Hz, 2H), 6.41 (d, J =
8.2 Hz, 4H), 6.20 (d, J = 8.5 Hz, 4H), 5.88 (d, J = 7.9 Hz, 2H),
3.69 (t, J = 6.5 Hz, 4H), 3.58 (t, J = 6.2 Hz, 2H), 2.37 (s, 6H),
2.26 (s, 6H), 1.70–1.58 (m, 6H), 1.48–1.35 (m, 6H), 1.01–0.84
(m, 9H). 13C NMR (100 MHz, CDCl3) δ 159.4, 157.1, 156.0,
146.7, 143.9, 138.5, 135.6, 134.2, 133.7, 132.6, 131.6, 130.9,
130.7, 129.3, 128.9, 128.5, 128.4, 127.4, 123.9, 113.5, 112.7,
68.3, 67.7, 67.6, 31.6, 30.0, 21.8, 21.4, 19.5, 14.2. HRMS (ESI)
calcd for C67H69N2O3 949.5308 (M + H), found 949.5314.
Method for the synthesis of 4c and 4d (Sonogashira coupling)
1o or 1p (1 mmol) and NH4OAc (20 mmol) were mixed in a
15 ml sealed tube reactor, HOAc (2 ml) was added and sealed,
then the mixture was heated to reflux for 20 h. After the mixture
was cooled to room temperature, water (100 mL) was added.
The mixture was filtered; the solid was washed with a small
amount of acetone and then heated to dryness. The resulting
crude product, 1-butyl-4-ethynylbenzene (8 mmol for 1o,
6 mmol for 1p), dry triethylamine (50 mL), and toluene (50 mL)
were added to a 150 mL round bottle flask equipped with a
Teflon covered magnetic stir bar, after the solution was purged
with nitrogen for 10 min, cuprous iodide (50 mg, 0. 25 mmol),
Pd(PPh3)4 (60 mg, 0.05 mol), PPh3 (50 mg, 0. 2 mmol) were
added. The mixture was refluxed under nitrogen for 24 h and
then cooled to room temperature. The mixture was filtered and
(Z)-2-((4,5-Bis(4-bromophenyl)-3-(4-butoxyphenyl)-2H-pyrrol-
2-ylidene)(4-butoxyphenyl)methyl)-4,5-bis(4-bromophenyl)-3-(4-
butoxyphenyl)-1H-pyrrole (2n). Reddish brown solid. m.p.
>300 °C. HRMS (ESI) calcd for C63H57Br4N2O3 1205.1103
(M + H), found 1205.1131.
Method for the synthesis of 4a and 4b (Suzuki coupling)
2e (113 mg, 0.1 mmol), appropriate arylboronic acid
(0.6 mmol), and K2CO3 (75 mg, 0.7 mmol) were taken in a
4 : 48 : 48 mixture of water–THF–toluene (50 mL) in a 100 mL
round-bottomed flask fitted with a reflux condenser and stirred
This journal is © The Royal Society of Chemistry 2012
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the filtration was evaporated under reduced pressure. The crude
product was purified by silica gel column chromatography using
hexane–dichloromethane (50 : 50) as eluent to afford 4c and 4d
in 61% and 64% yields, respectively.
132.4, 132.1, 132.0, 131.3, 130.9, 130.4, 29.0, 127.7, 127.6,
127.3, 126.7, 126.5, 126.0. HRMS (EI) calcd for C51H35BF2N2
724.2861 (M+), found 724.2869.
2,3,7,8-Tetrakis(4-butylphenyl)-5,5-difluoro-1,9,10-triphenyl-
5H-dipyrrolo[1,2-c:2′,1′-f][1,3,2]diazaborinin-4-ium-5-uide (3b).
(Z)-2-((4,5-Bis(4-((4-butylphenyl)ethynyl)phenyl)-3-phenyl-
2H-pyrrol-2-ylidene)(phenyl)methyl)-4,5-bis(4-((4-butyl phenyl)-
ethynyl)phenyl)-3-phenyl-1H-pyrrole (4c). Purple solid. m.p.
1
Brown solid. m.p. 162–163 °C. H NMR (400 MHz, CDCl3)
δ 7.34 (d, J = 8.0 Hz, 4H), 7.04 (d, J = 8.1 Hz, 4H), 6.85 (d, J =
7.1 Hz, 2H), 6.80–6.65 (m, 10H), 6.57 (dd, J = 13.3, 6.2 Hz,
5H), 6.48 (d, J = 8.1 Hz, 4H), 6.40 (t, J = 7.7 Hz, 2H),
2.63–2.54 (m, 4H), 2.46–2.38 (m, 4H), 1.60 (dd, J = 15.2,
7.4 Hz, 4H), 1.45 (dt, J = 15.3, 7.5 Hz, 4H), 1.38–1.31 (m, 4H),
1.23 (dd, J = 14.9, 7.4 Hz, 4H), 0.92 (t, J = 7.3 Hz, 6H), 0.86
(t, J = 7.3 Hz, 6H). 13C NMR (100 MHz, CDCl3) δ 156.6,
146.6, 144.0, 143.6, 140.8, 135.1, 132.4, 132.2, 131.5, 130.9,
130.8, 130.7, 130.5, 129.4, 128.8, 127.7, 127.6, 127.2, 126.6,
125.8, 35.8, 35.4, 33.4, 33.3, 22.6, 22.5, 14.3, 14.2. HRMS
(ESI) calcd for C67H66BF2N2 947.5287 (M − H), found 947.5403.
1
147–148 °C. H NMR (400 MHz, CDCl3) δ 14.98 (s, 1H), 7.49
(d, J = 9.3 Hz, 12H), 7.41 (d, J = 7.7 Hz, 4H), 7.30 (s, 1H), 7.24
(s, 1H), 7.21–7.13 (m, 8H), 6.93 (d, J = 7.8 Hz, 3H), 6.82 (d,
J = 6.9 Hz, 3H), 6.73 (d, J = 6.5 Hz, 2H), 6.68 (t, J = 6.9 Hz,
4H), 6.53 (d, J = 6.5 Hz, 5H), 6.37 (t, J = 7.3 Hz, 2H), 2.63 (dd,
J = 15.5, 7.8 Hz, 8H), 1.61 (dd, J = 14.6, 7.4 Hz, 8H), 1.37
(dt, J = 14.1, 7.1 Hz, 8H), 0.94 (dd, J = 12.2, 7.0 Hz, 12H). 13C
NMR (125 MHz, CDCl3) δ 143.9, 143.8, 143.6, 140.5, 138.9,
135.5, 135.2, 135.1, 133.3, 133.0, 132.6, 132.5, 132.4, 132.3,
132.1, 132.0, 131.9, 131.7, 131.4, 131.3, 130.9, 130.5, 128.8,
128.7, 128.5, 128.4, 127.1, 127.0, 126.5, 125.6, 125.5, 124.8,
123.9, 123.8, 121.7, 120.6, 120.5, 91.7, 90.2, 89.2, 89.1, 35.9,
35.8, 33.7, 22.6, 14.2. HRMS (ESI) calcd for C99H85N2
1301.6713 (M + H), found 1301.6740.
2,3,7,8-Tetrakis(4-butylphenyl)-5,5-difluoro-1,9,10-tris(4-methoxy-
phenyl)-5H-dipyrrolo[1,2-c:2′,1′-f][1,3,2]diazaborinin-4-ium-5-uide
1
(3c). Brown solid. m.p. >300 °C. H NMR (400 MHz, CDCl3)
δ 7.31 (d, J = 7.9 Hz, 4H), 7.03 (d, J = 7.9 Hz, 4H), 6.72 (dd,
J = 15.5, 8.2 Hz, 6H), 6.49 (dd, J = 18.6, 8.2 Hz, 8H), 6.27 (d,
J = 8.5 Hz, 4H), 5.97 (d, J = 8.5 Hz, 2H), 3.62 (s, 6H), 3.55 (s,
3H), 2.57 (t, J = 7.7 Hz, 4H), 2.43 (t, J = 7.6 Hz, 4H), 1.63–1.42
(m, 8H), 1.29 (ddd, J = 24.6, 14.8, 7.4 Hz, 8H), 0.89 (dt, J =
19.6, 7.3 Hz, 12H). 13C NMR (100 MHz, CDCl3) δ 159.8,
157.5, 156.2, 146.4, 143.6, 143.4, 140.7, 134.5, 133.7, 132.6,
131.7, 130.9, 130.8, 129.5, 127.7, 127.6, 124.2, 112.9, 112.3,
55.3, 55.2, 35.8, 35.51, 33.52, 33.4, 22.6, 22.5, 14.3, 14.2.
HRMS (ESI) calcd for C70H72BF2N2O3 1037.5604 (M − H),
found 1037.5742.
(Z)-2-((4,5-Bis(4-((4-butylphenyl)ethynyl)phenyl)-3-phenyl-
2H-pyrrol-2-ylidene)(phenyl)methyl)-4,5-bis(4-((4-butyl phenyl)-
ethynyl)phenyl)-3-phenyl-1H-pyrrole (4d). Purple solid. m.p.
1
169–170 °C. H NMR (400 MHz, CDCl3) δ 15.04 (s, 1H), 7.74
(dd, J = 13.1, 7.4 Hz, 3H), 7.50 (dd, J = 16.1, 8.8 Hz, 14H),
7.41 (d, J = 7.9 Hz, 3H), 7.35 (d, J = 6.3 Hz, 3H), 7.22–7.12
(m, 7H), 6.94 (dd, J = 15.4, 7.3 Hz, 3H), 6.82 (d, J = 6.8 Hz,
3H), 6.69 (t, J = 15.6 Hz, 3H), 6.53 (d, J = 6.2 Hz, 3H), 6.40
(dd, J = 18.3, 9.0 Hz, 2H), 2.68–2.56 (m, 6H), 1.61 (t, J =
10.7 Hz, 6H), 1.37 (dt, J = 14.2, 6.9 Hz, 6H), 0.94 (dd, J = 12.3,
6.9 Hz, 9H). HRMS (ESI) calcd for C87H73N2 1145.5774
(M + H), found 1145.5701.
2,3,7,8-Tetrakis(4-butylphenyl)-5,5-difluoro-1,9,10-tri-p-tolyl-
5H-dipyrrolo[1,2-c:2′,1′-f][1,3,2]diazaborinin-4-ium-5-uide (3d).
1
Brown solid. m.p. 206–207 °C. H NMR (400 MHz, CDCl3) δ
General procedure for the synthesis of 3 and 5
7.31 (d, J = 8.0 Hz, 4H), 7.02 (d, J = 8.0 Hz, 4H), 6.72 (d, J =
8.0 Hz, 4H), 6.62 (d, J = 7.9 Hz, 2H), 6.50 (dd, J = 11.9,
8.1 Hz, 8H), 6.41 (d, J = 7.9 Hz, 4H), 6.17 (d, J = 7.9 Hz, 2H),
2.57 (t, J = 7.7 Hz, 4H), 2.42 (t, J = 7.7 Hz, 4H), 2.10 (s, 6H),
1.98 (s, 3H), 1.62–1.52 (m, 4H), 1.50–1.41 (m, 4H), 1.32 (dd,
J = 14.9, 7.4 Hz, 4H), 1.23 (dd, J = 14.9, 7.4 Hz, 4H), 0.91 (t,
J = 7.3 Hz, 6H), 0.86 (t, J = 7.3 Hz, 6H). 13C NMR (125 MHz,
CDCl3) δ 156.3, 147.0, 144.1, 143.4, 140.6, 138.3, 135.1, 134.6,
132.6, 132.18, 132.17, 130.99, 130.97, 130.86, 130.4, 129.6,
128.8, 127.8, 127.7, 127.5, 127.0, 35.8, 35.5, 33.48, 33.3, 22.6,
22.5, 21.3, 21.2, 14.29, 14.25. HRMS (ESI) calcd for
C70H72BF2N2 989.5757 (M − H), found 989.5852.
To a solution of heptaaryldipyrromethene (2a–2p or 4a–4d,
0.2 mmol) in dry CH2Cl2 (50 mL) was added an excess of Et3N
(0.42 mL, 3.0 mmol) under N2 atmosphere, and the reaction
mixture was allowed to stir under refluxing for 15 min, followed
by the addition of BF3·OEt2 (0.45 mL, 3.6 mmol). The mixture
was stirred for an additional 2 h under refluxing until TLC analy-
sis indicated the complete disappearance of heptaaryldipyrro-
methene. Then the mixture was cooled to room temperature and
water (150 mL) was added. The mixture was extracted with
CH2Cl2, the organic layer was dried over MgSO4 and the solvent
was then removed on a rotary evaporator under vacuum. The
crude product was purified by silica gel column chromatography
with hexane–CH2Cl2 (90 : 10) as eluent to afford 3.
1,9,10-Tris(4-bromophenyl)-2,3,7,8-tetrakis(4-butylphenyl)-5,5-
difluoro-5H-dipyrrolo[1,2-c:2′,1′-f][1,3,2]diazaborinin-4-ium-5-uide
(3e). Brown solid. m.p. 257–258 °C. 1H NMR (400 MHz,
CDCl3) δ 7.32 (d, J = 8.0 Hz, 4H), 7.05 (d, J = 8.0 Hz, 4H),
6.94 (d, J = 8.3 Hz, 4H), 6.77 (d, J = 8.0 Hz, 4H), 6.72 (d, J =
8.3 Hz, 2H), 6.64 (d, J = 8.2 Hz, 2H), 6.52 (d, J = 8.0 Hz, 4H),
6.44 (d, J = 8.2 Hz, 4H), 2.63–2.55 (m, 4H), 2.49–2.38 (m, 4H),
1.59 (dt, J = 15.3, 7.6 Hz, 4H), 1.54–1.44 (m, 4H), 1.30 (m,
8H), 0.91 (dt, J = 17.9, 7.3 Hz, 12H). HRMS (ESI) calcd for
C67H63BBr3F2N2 1181.2602 (M − H), found 1181.2709.
5,5-Difluoro-1,2,3,7,8,9,10-heptaphenyl-5H-dipyrrolo[1,2-c:2′,1′-f]-
[1,3,2]diazaborinin-4-ium-5-uide (3a).14 Brown solid. m.p.
>300 °C (>300 °C).13 1H NMR (400 MHz, CDCl3) δ 7.42
(d, J = 7.3 Hz, 4H), 7.28 (d, J = 6.6 Hz, 1H), 7.25–7.18
(m, 6H), 6.98–6.88 (m, 6H), 6.85 (d, J = 7.9 Hz, 2H), 6.75 (d,
J = 7.1 Hz, 2H), 6.68 (t, J = 7.5 Hz, 4H), 6.63–6.58 (m, 4H),
6.55 (d, J = 7.9 Hz, 4H), 6.40 (t, J = 7.6 Hz, 2H). 13C NMR
(100 MHz, CDCl3) δ 156.4, 147.6, 144.5, 135.1, 134.8, 133.3,
8856 | Org. Biomol. Chem., 2012, 10, 8848–8859
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2,3,7,8-Tetrakis(4-butylphenyl)-5,5-difluoro-1,9,10-tris(4-(tri-
fluoromethyl)phenyl)-5H-dipyrrolo[1,2-c:2′,1′-f][1,3,2]diazaborinin-
4-ium-5-uide (3f). Brown solid. m.p. 214–215 °C. 1H NMR
(400 MHz, CDCl3) δ 7.33 (d, J = 7.9 Hz, 4H), 7.06 (d, J =
8.0 Hz, 4H), 6.99 (d, J = 8.1 Hz, 4H), 6.94 (d, J = 7.9 Hz, 2H),
6.79–6.64 (m, 10H), 6.47 (d, J = 8.0 Hz, 4H), 2.59 (t, J =
7.7 Hz, 4H), 2.43 (t, J = 7.7 Hz, 4H), 1.63–1.53 (m, 4H), 1.45
(dt, J = 15.3, 7.7 Hz, 4H), 1.33 (dd, J = 14.8, 7.4 Hz, 4H), 1.22
(dd, J = 14.8, 7.4 Hz, 4H), 0.92 (t, J = 7.3 Hz, 6H), 0.86 (t, J =
7.3 Hz, 6H). HRMS (ESI) calcd for C70H63BF11N2 1151.4909
(M − H), found 1151.4979.
J = 8.4 Hz, 4H), 6.27 (d, J = 8.4 Hz, 4H), 5.96 (d, J = 8.5 Hz,
2H), 3.73 (t, J = 6.5 Hz, 4H), 3.64 (t, J = 6.5 Hz, 2H), 1.67 (dd,
J = 14.4, 6.8 Hz, 6H), 1.44 (dd, J = 14.8, 7.4 Hz, 6H), 0.98 (dt,
J = 14.7, 7.4 Hz, 9H). 13C NMR (100 MHz, CDCl3) δ 159.7,
157.3, 155.9, 147.7, 144.3, 134.5, 133.7, 132.6, 132.2, 131.6,
131.1, 131.0, 128.8, 127.7, 127.1, 126.3, 123.8, 113.6, 112.9,
67.8, 31.7, 19.5, 14.2. HRMS (ESI) calcd for C63H58BF2N2O3
939.4509 (M − H), found 939.4645.
1,9,10-Tris(4-(tert-butyl)phenyl)-5,5-difluoro-2,3,7,8-tetraphenyl-
5H-dipyrrolo[1,2-c:2′,1′-f][1,3,2]diazaborinin-4-ium-5-uide (3k).
1
Brown solid. m.p. >300 °C. H NMR (400 MHz, CDCl3) δ 7.40
2,3,7,8-Tetrakis(4-butylphenyl)-5,5-difluoro-1,9,10-tris(4-fluoro-
phenyl)-5H-dipyrrolo[1,2-c:2′,1′-f][1,3,2]diazaborinin-4-ium-5-uide
(3g). Brown solid. m.p. 167–168 °C. 1H NMR (400 MHz,
CDCl3) δ 7.31 (d, J = 8.0 Hz, 4H), 7.04 (d, J = 7.8 Hz, 6H),
6.74 (d, J = 7.9 Hz, 4H), 6.55–6.44 (m, 12H), 6.21 (t, J =
8.6 Hz, 2H), 2.63–2.53 (m, 4H), 2.43 (t, J = 7.7 Hz, 4H),
1.61–1.53 (m, 4H), 1.49–1.42 (m, 4H), 1.35–1.21 (m, 8H), 0.89
(d, J = 7.0 Hz, 4H), 7.26–7.21 (m, 5H), 6.94 (dd, J = 14.6,
7.6 Hz, 4H), 6.85 (t, J = 7.4 Hz, 4H), 6.75 (d, J = 8.1 Hz, 4H),
6.48 (dd, J = 15.4, 7.6 Hz, 10H), 1.12 (s, 18H), 1.01 (s, 9H).
13C NMR (100 MHz, CDCl3) δ 156.0, 152.0, 148.7, 148.3,
144.7, 135.5, 133.7, 132.5, 132.2, 132.1, 131.0, 130.9, 130.1,
129.3, 128.8, 127.7, 127.4, 126.2, 124.0, 123.4, 34.5, 34.4,
31.6, 31.5. HRMS (EI) calcd for C63H59BF2N2 892.4739 (M+),
found 892.4747.
(dt,
J = 19.6, 7.3 Hz, 12H). HRMS (ESI) calcd for
C67H63BF5N2 1001.5004 (M − H), found 1001.5048.
5,5-Difluoro-1,9,10-tris(3-methoxyphenyl)-2,3,7,8-tetraphenyl-
5H-dipyrrolo[1,2-c:2′,1′-f][1,3,2]diazaborinin-4-ium-5-uide (3l).
Brown solid. m.p. >300 °C. H NMR (400 MHz, CDCl3) δ 7.42
1,9,10-Tri([1,1′-biphenyl]-4-yl)-2,3,7,8-tetrakis(4-butylphenyl)-
5,5-difluoro-5H-dipyrrolo[1,2-c:2′,1′-f][1,3,2]diazaborinin-4-ium-
5-uide (3h). Brown solid. m.p. 255–256 °C. 1H NMR
(400 MHz, CDCl3) δ 7.38 (d, J = 7.7 Hz, 4H), 7.30–7.18 (m,
10), 7.15–7.03 (m, 5H), 6.94 (dd, J = 17.5, 7.6 Hz, 8H), 6.86
(d, J = 7.5 Hz, 2H), 6.76 (d, J = 7.7 Hz, 4H), 6.69 (d, J =
7.7 Hz, 4H), 6.60 (dd, J = 15.8, 7.7 Hz, 6), 2.60 (t, J = 7.6 Hz,
4H), 2.44 (t, J = 7.5 Hz, 4H), 1.67–1.56 (m, 4H), 1.53–1.42 (m,
4H), 1.42–1.32 (m, 4H), 1.25 (td, J = 14.5, 7.1 Hz, 4H), 0.94
(t, J = 7.3 Hz, 6H), 0.87 (t, J = 7.3 Hz, 6H). 13C NMR
(100 MHz, CDCl3) δ 156.8, 146.0, 143.6, 143.5, 141.8, 140.9,
140.8, 140.5, 138.4, 135.1, 134.4, 132.8, 132.5, 131.0, 130.9,
130.7, 129.4, 128.7, 128.4, 127.8, 127.7, 127.5, 127.29, 127.25,
127.21, 125.9, 125.4, 35.8, 35.5, 33.4, 33.3, 22.6, 22.5, 14.3,
14.2. HRMS (ESI) calcd for C85H78BFN2 1156.6242 (M − HF),
found 1156.6340.
1
(d, J = 6.6 Hz, 4H), 7.26 (dd, J = 14.1, 4.9 Hz, 6H), 6.96 (dd,
J = 15.4, 7.5 Hz, 6H), 6.69 (dd, J = 29.1, 7.4 Hz, 6H),
6.53–6.44 (m, 4H), 6.34–6.23 (m, 4H), 6.03–5.94 (m, 2H), 3.62
(s, 6H), 3.56 (s, 3H). 13C NMR (100 MHz, CDCl3) δ 159.9,
157.7, 156.0, 147.5, 144.1, 134.5, 133.7, 133.5, 132.6, 132.2,
132.1, 131.6, 131.0, 131.0, 128.9, 127.8, 127.7, 127.3, 126.4,
124.0, 113.0, 112.4, 55.3, 55.2. HRMS (ESI) calcd for
C54H42BF2N2O3 815.3257 (M + H), found 815.3182.
1,9,10-Tris(4-butoxyphenyl)-5,5-difluoro-2,3,7,8-tetra-p-tolyl-
5H-dipyrrolo[1,2-c:2′,1′-f][1,3,2]diazaborinin-4-ium-5-uide (3m).
1
Brown solid. m.p. 241–242 °C. H NMR (400 MHz, CDCl3)
δ 7.31 (d, J = 7.9 Hz, 4H), 7.03 (d, J = 7.9 Hz, 4H), 6.75 (d, J =
7.9 Hz, 4H), 6.67 (d, J = 8.5 Hz, 2H), 6.53 (d, J = 7.9 Hz, 4H),
6.44 (d, J = 8.5 Hz, 4H), 6.26 (d, J = 8.5 Hz, 4H), 5.94 (d, J =
8.5 Hz, 2H), 3.73 (t, J = 6.6 Hz, 4H), 3.63 (t, J = 6.6 Hz, 2H),
2.30 (s, 6H), 2.16 (s, 6H), 1.67 (dd, J = 14.6, 6.9 Hz, 6H),
1.48–1.40 (m, 6H), 0.98 (dd, J = 12.5, 5.1 Hz, 9H). 13C NMR
(125 MHz, CDCl3) δ 159.5, 157.2, 155.9, 146.9, 144.0, 138.6,
135.7, 134.2, 133.6, 132.5, 131.5, 130.8, 130.6, 129.4, 128.9,
128.4, 128.3, 127.3, 123.8, 113.5, 112.7, 67.78, 67.75, 31.6,
30.0, 21.7, 21.3, 19.6, 19.5, 14.17, 14.15. HRMS (ESI) calcd for
C67H66BF2N2O3 995.5135 (M − H), found 995.5239.
2,3,7,8-Tetrakis(4-butylphenyl)-5,5-difluoro-1,9,10-tris(3-methoxy-
phenyl)-5H-dipyrrolo[1,2-c:2′,1′-f][1,3,2]diazaborinin-4-ium-5-uide
(3i). Brown solid. m.p. 235–236 °C. 1H NMR (400 MHz,
CDCl3) δ 7.30 (d, J = 7.7 Hz, 4H), 7.02 (d, J = 7.7 Hz, 4H),
6.71 (dd, J = 18.2, 8.0 Hz, 6H), 6.48 (dd, J = 17.9, 7.9 Hz, 8H),
6.27 (d, J = 8.3 Hz, 4H), 5.96 (d, J = 8.2 Hz, 2H), 3.61 (s, 6H),
3.55 (s, 3H), 3.20 (q, J = 7.2 Hz, 4H), 2.96 (d, J = 7.0 Hz, 4H),
2.56 (t, J = 7.6 Hz, 4H), 2.42 (t, J = 7.6 Hz, 4H), 1.57 (dt,
J = 15.2, 7.6 Hz, 4H), 1.46 (dt, J = 15.2, 7.6 Hz, 4H), 0.88 (dt,
J = 19.3, 7.3 Hz, 6H). 13C NMR (100 MHz, CDCl3) δ 159.7,
157.5, 156.1, 146.4, 143.6, 143.4, 140.6, 134.5, 133.7, 132.5,
131.6, 130.9, 130.8, 129.5, 127.7, 127.63, 127.60, 124.2, 112.9,
112.3, 55.3, 55.1, 35.8, 35.4, 33.4, 33.3, 22.6, 22.5, 14.29,
14.26. HRMS (ESI) calcd for C70H72BF2N2O3 1037.5604
(M − H), found 1037.5743.
2,3,7,8-Tetrakis(4-bromophenyl)-1,9,10-tris(4-butoxyphenyl)-
5,5-difluoro-5H-dipyrrolo[1,2-c:2′,1′-f][1,3,2]diazaborinin-4-ium-
5-uide (3n). Brown solid. m.p. 298–300 °C. 1H NMR
(400 MHz, CDCl3) δ 7.38 (d, J = 8.2 Hz, 4H), 7.23 (d, J = 8.2
Hz, 4H), 7.09 (d, J = 8.2 Hz, 4H), 6.65 (d, J = 8.3 Hz, 2H), 6.47
(d, J = 8.2 Hz, 4H), 6.39 (d, J = 8.4 Hz, 4H), 6.26 (d, J =
8.4 Hz, 4H), 5.93 (d, J = 8.4 Hz, 2H), 3.71 (t, J = 6.5 Hz, 4H),
3.60 (t, J = 6.5 Hz, 2H), 1.65 (dd, J = 17.0, 9.4 Hz, 4H), 1.42
(dd, J = 14.8, 7.4 Hz, 4H), 0.95 (t, J = 7.4 Hz, 6H). 13C NMR
(100 MHz, CDCl3) δ 160.0, 157.6, 154.56, 148.58, 144.8,
133.6, 133.2, 132.9, 132.5, 132.2, 131.51, 131.3, 131.2, 130.6,
126.4, 123.9, 123.3, 121.0, 113.9, 113.0, 67.9, 31.6, 19.5, 14.2.
1,9,10-Tris(4-butoxyphenyl)-5,5-difluoro-2,3,7,8-tetraphenyl-
5H-dipyrrolo[1,2-c:2′,1′-f][1,3,2]diazaborinin-4-ium-5-uide (3j).
1
Brown solid. m.p. 260–261 °C. H NMR (400 MHz, CDCl3)
δ 7.41 (d, J = 7.0 Hz, 4H), 7.27–7.17 (m, 6H), 6.99–6.91 (m,
6H), 6.71 (d, J = 8.5 Hz, 2H), 6.65 (d, J = 7.0 Hz, 4H), 6.46 (d,
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HRMS (EI) calcd for C63H55BBr4F2N2O3 1252.1007 (M+),
found 1252.1079.
J = 7.5 Hz, 2H), 6.74 (t, J = 7.3 Hz, 5H), 6.62 (d, J = 5.0 Hz,
2H), 6.57 (dd, J = 12.4, 5.4 Hz, 6H), 6.50 (d, J = 8.3 Hz, 3H),
6.43 (t, J = 7.5 Hz, 3H), 2.62 (dd, J = 17.2, 9.4 Hz, 8H),
1.69–1.52 (m, 8H), 1.37 (dt, J = 15.2, 7.6 Hz, 8H), 0.94 (q, J =
7.4 Hz, 12H). HRMS (ESI) calcd for C99H82BF2N2 1347.6539
(M − H), found 1347.6617.
2,3,7,8-Tetrakis(4-bromophenyl)-5,5-difluoro-1,9,10-triphenyl-
5H-dipyrrolo[1,2-c:2′,1′-f][1,3,2]diazaborinin-4-ium-5-uide (3o).
1
Brown solid. m.p. >300 °C. H NMR (400 MHz, CDCl3) δ 7.42
(d, J = 8.4 Hz, 4H), 7.28 (d, J = 7.9 Hz, 4H), 7.08 (d, J =
8.4 Hz, 4H), 6.84–6.77 (m, 4H), 6.72 (t, J = 7.5 Hz, 4H), 6.61
(t, J = 7.5 Hz, 1H), 6.52 (d, J = 7.2 Hz, 4H), 6.47 (d, J = 8.4 Hz,
4H), 6.41 (t, J = 7.7 Hz, 2H). HRMS (ESI) calcd for
C51H30BBr4FN2 1015.9220 (M − HF), found 1015.9317.
1,9,10-Tris(4-((4-butylphenyl)ethynyl)phenyl)-5,5-difluoro-
2,3,7,8-tetraphenyl-5H-dipyrrolo[1,2-c:2′,1′-f][1,3,2]diazaborinin-
4-ium-5-uide (5d). Brown solid. m.p. 199–200 °C. 1H NMR
(500 MHz, CDCl3) δ 7.44–7.37 (m, 12H), 7.33 (d, J = 8.0 Hz,
2H), 7.14 (dd, J = 6.9, 4.7 Hz, 4H), 7.09 (dd, J = 7.9, 4.1 Hz,
4H), 6.94 (d, J = 7.3 Hz, 2H), 6.87–6.83 (m, 2H), 6.82–6.76 (m,
4H), 6.71 (t, J = 7.5 Hz, 4H), 6.61 (dd, J = 7.3, 1.8 Hz, 4H),
6.58–6.53 (m, 4H), 6.47 (d, J = 8.2 Hz, 2H), 2.60 (dd, J = 13.3,
6.8 Hz, 6H), 1.58 (dt, J = 15.1, 6.8 Hz, 6H), 1.36–1.30 (m, 6H),
0.97–0.90 (m, 9H). HRMS (ESI) calcd for C87H70BF2N2
1191.5600 (M − H), found 1191.5671.
1,9,10-Tris(4-bromophenyl)-5,5-difluoro-2,3,7,8-tetraphenyl-
5H-dipyrrolo[1,2-c:2′,1′-f][1,3,2]diazaborinin-4-ium-5-uide (3p).
1
Brown solid. m.p. >300 °C. H NMR (400 MHz, CDCl3) δ 7.42
(d, J = 8.3 Hz, 4H), 7.27 (d, J = 4.6 Hz, 3H), 7.09 (d, J =
8.2 Hz, 4H), 6.80 (t, J = 7.1 Hz, 4H), 6.72 (t, J = 7.4 Hz, 4H),
6.61 (t, J = 6.6 Hz, 1H), 6.54–6.49 (m, 4H), 6.46 (d, J = 8.4 Hz,
4H), 6.41 (t, J = 7.7 Hz, 2H). HRMS (EI) calcd for
C51H32BBr3F2N2 958.0177 (M+), found 958.0287.
Acknowledgements
2,3,7,8-Tetrakis(4-butylphenyl)-5,5-difluoro-1,9,10-tris(4′-methyl-
[1,1′-biphenyl]-4-yl)-5H-dipyrrolo[1,2-c:2′,1′-f][1,3,2]diazaborinin-
4-ium-5-uide (5a). Brown solid. m.p. 235–236 °C. 1H NMR
(400 MHz, CDCl3) δ 7.35 (d, J = 7.8 Hz, 4H), 7.14 (d, J =
7.8 Hz, 4H), 7.04 (t, J = 8.1 Hz, 8H), 6.92 (d, J = 7.9 Hz, 6H),
6.74 (d, J = 6.8 Hz, 8H), 6.63 (d, J = 7.8 Hz, 4H), 6.56 (t, J =
6.8 Hz, 6H), 2.59 (t, J = 7.6 Hz, 4H), 2.43 (t, J = 7.6 Hz, 4H),
2.35 (s, 6H), 2.29 (s, 3H), 1.64–1.54 (m, 4H), 1.45 (dd, J =
14.8, 7.6 Hz, 4H), 1.33 (dd, J = 15.0, 7.5 Hz, 4H), 1.26–1.18
(m, 4H), 0.92 (t, J = 7.4 Hz, 6H), 0.86 (t, J = 7.3 Hz, 6H).
13C NMR (125 MHz, CDCl3) δ 156.6, 146.2, 143.7, 143.6,
141.8, 140.8, 138.4, 138.0, 137.8, 136.8, 135.0, 134.0, 132.7,
132.5, 131.01, 130.96, 130.9, 130.7, 130.6, 129.5, 129.4, 129.1,
127.8, 127.7, 127.4, 127.1, 125.7, 125.2, 35.8, 35.51, 33.49,
33.4, 22.6, 22.5, 21.3, 14.3, 14.2. HRMS (ESI) calcd for
C88H84BF2N2 1217.6696 (M − H), found 1217.6786.
This work has been supported by the National Nature Science
Foundation of China (No. 20972137, 21032005).
Notes and references
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4-ium-5-uide (5b). Brown solid. m.p. 237–238 °C. 1H NMR
(400 MHz, CDCl3) δ 7.32 (d, J = 7.9 Hz, 4H), 7.15 (d, J =
8.5 Hz, 4H), 7.03 (d, J = 7.9 Hz, 4H), 6.87 (d, J = 7.9 Hz, 6H),
6.74 (dd, J = 16.6, 8.2 Hz, 10H), 6.60 (d, J = 7.9 Hz, 4H),
6.56–6.49 (m, 6H), 6.46 (d, J = 8.4 Hz, 2H), 3.78 (s, 6H), 3.72
(s, 3H), 2.56 (t, J = 7.7 Hz, 4H), 2.40 (t, J = 7.6 Hz, 4H), 1.55
(q, J = 7.5 Hz, 4H), 1.43 (dd, J = 15.2, 7.9 Hz, 4H), 1.31 (dd,
J = 14.8, 7.4 Hz, 4H), 1.21 (dd, J = 16.0, 8.6 Hz, 4H), 0.90 (t,
J = 7.3 Hz, 6H), 0.84 (t, J = 7.3 Hz, 6H). 13C NMR (100 MHz,
CDCl3) δ 159.2, 156.6, 146.2, 143.7, 143.6, 141.3, 140.8, 138.0,
135.0, 133.7, 133.5, 133.2, 132.8, 132.6, 131.0, 130.9, 130.8,
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113.8, 55.6, 55.4, 35.8, 35.5, 33.5, 33.4, 22.6, 22.5, 14.3, 14.2.
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found 1265.6651.
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7.9 Hz, 3H), 7.20–7.06 (m, 13H), 6.87–6.82 (m, 3H), 6.80 (d,
8858 | Org. Biomol. Chem., 2012, 10, 8848–8859
This journal is © The Royal Society of Chemistry 2012

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Org. Biomol. Chem., 2012, 10, 8848–8859 | 8859