Cross-Dehydrogenative Coupling (CDC) as Key-Transformations to Various D-π-A Organic Dyes: C-H/C-H Synthetic Study Directed toward Dye-Sensitized Solar Cells Applications

Article abstract of DOI:10.1021/acs.joc.7b00054

A variety of push-pull type organic dyes are facilely synthesized through the most atom-economical C-H/C-H dehydrogenative coupling reactions. After comprehensive synthetic optimizations, a broad substrate scope is achieved and functional groups, such as ester, ketone, nitrile, nitro, and triazene are well tolerated. The sensitive aldehyde group required for the conversion into anchoring groups for DSSCs applications is also compatible under present oxidant-containing reaction conditions. Based on this optimum C-H/C-H coupling approach, three new organic sensitizers are readily prepared and submitted to solar cell device fabrications, giving the power conversion efficiency (PCE) up to 4.85%. This work constitutes the first example that connects high atom-efficiency C-H/C-H green catalysis with dye-sensitized solar cell applications.

Full text of DOI:10.1021/acs.joc.7b00054

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Article
Cross-Dehydrogenative Coupling (CDC) as Key-Transformations
to Various D-#-A Organic Dyes: C-H/C-H Synthetic Study
directed toward Dye-Sensitized Solar Cells Applications
Yan-Syun Ciou, Po-Han Lin, Wei-Ming Li, Kun-Mu Lee, and Ching-Yuan Liu
J. Org. Chem., Just Accepted Manuscript • DOI: 10.1021/acs.joc.7b00054 • Publication Date (Web): 07 Mar 2017
Downloaded from http://pubs.acs.org on March 8, 2017
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Cross-Dehydrogenative Coupling (CDC) as Key-Transformations
to Various D-π-A Organic Dyes: C-H/C-H Synthetic Study
directed toward Dye-Sensitized Solar Cells Applications
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YanꢀSyun Ciou,† PoꢀHan Lin,† WeiꢀMing Li,† KunꢀMu Lee,‡ and ChingꢀYuan Liu*,†
†Department of Chemical and Materials Engineering, National Central University,
Jhongli District 320, Taiwan (R.O.C) *Eꢀmail: cyliu0312@ncu.edu.tw
‡Department of Chemical and Materials Engineering, Chang Gung University,
Guishan District 333, Taiwan (R.O.C)
Abstract: A variety of pushꢀpull type organic dyes are facilely synthesized through the most
atomꢀeconomical CꢀH/CꢀH dehydrogenative coupling reactions. After comprehensive synthetic
optimizations, a broad substrate scope is achieved and functional groups such as ester, ketone,
nitrile, nitro, and triazene are well tolerated. The sensitive aldehyde group required for the
conversion into anchoring groups for DSSCs applications is also compatible under present
oxidantꢀcontaining reaction conditions. Based on this optimum CꢀH/CꢀH coupling approach, three
new organic sensitizers are readily prepared and submitted to solar cell device fabrications, giving
the power conversion efficiency (PCE) up to 4.85%. This work constitutes the first example that
connects high atomꢀefficiency CꢀH/CꢀH green catalysis with dyeꢀsensitized solar cell applications.
Introduction
Conversion of sunlight into electric power is one of the most promising green techniques for
renewable energy.1 Differing from the firstꢀgeneration siliconꢀbased photovoltaic cells, Grätzel and
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coꢀworkers designed efficient and inexpensive dyeꢀsensitized solar cells (DSSCs) using a series of
organometallic complexes as dyeꢀsensitizers.2ꢀ6 Among various dyes, metalꢀfree organic
sensitizers have been attracting considerable research interests since last decade because they had
advantages of low cost, high extinction coefficient, and diverse molecular design.7ꢀ11 Synthetically,
accessing these D−π−A type dye molecules traditionally relied on Suzukiꢀ or Stilleꢀcoupling
reaction, which involves tedious preꢀfunctionalization steps and requires the preparation of costly
organoboron or toxic organotin species. With the aim of developing a stepꢀsaving and
userꢀfriendly synthetic approach for DSSCs, Fagnou,12 Mori,13 Marder,14 and our group15 reported
alternative ways to access D−π−A organic dyes via direct CꢀH arylations (CꢀH/CꢀX). In order to
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further simplify the synthetic efficiency, we envisaged that D−π−A or D−Α'−π−A configured dyes
could be facilely constructed through the most stepꢀeconomical CꢀH/CꢀH coupling method that
might be facilitated coincidentally by the difference of proton acidity between two key
components of an unsymmetrical dye molecule: Donor−H and Acceptor−H. Therefore, we
demonstrate herein an inꢀdepth synthetic study of crossꢀdehydrogenative couplings (CDC)16
directed toward dyeꢀsensitized solar cell applications (Scheme 1). To the best of our knowledge,
no reports on the connection of CꢀH/CꢀH coupling methodologies with the metalꢀfree dye
sensitizers for DSSCs have appeared to date.
Scheme 1. The evolution of synthetic strategies for metal-free organic dye sensitizers: from
C−[M]/C−X through C−/C−X to C−H/C−H.
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Results and Discussion
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Since we aimed to obtain an unsymmetrical D−π−A type dye molecule 3a through optimized
crossꢀdehydrogenative couplings (CDC), triphenylamineꢀsubstituted thiophene 1a and
2ꢀthiophenecarboxaldehyde 2a were directly coupled under various kinds of reaction conditions
(results summarized in Table 1). Firstly, the CꢀH/CꢀH coupling reaction was conducted in
nonpolar oꢀxylene using Pd(OAc)2 as catalyst, Cu(OAc)2 as oxidant, and K2CO3 as base. Desired
product 3a was isolated in only 8% yield (entry 1). Likewise, Cs2CO3 and K3PO4 gave poor
yields of 3a (7%, entries 2ꢀ3) and we found a significant amount of unreacted starting materials
(1a, 2a) along with some homocoupled adduct from 1a. In the presence of strong base such as
LiOtBu or KOtBu, product 3a was not generated and both starting materials were recovered
(entries 4ꢀ5). Nꢀcontaining aliphatic bases were also less efficient for the CDC reactions (0~29%,
entries 6ꢀ10), whereas the aromatic ones (prydine, DMAP) gave promising yields and we were
pleased to isolate 3a in 66%, 57% respectively (entries 11, 12). We then fixed on the use of
pyridine as optimum base and proceeded to the screening of various oxidants. 3a was obtained in
44% yield using Cu(OAc)2 monohydrate as oxidant (entry 13), while other Cu(II)ꢀbased oxidants
were shown to be ineffective (0~10%, entries 14ꢀ16). Subsequently, a series of Ag(I)ꢀbased
oxidants were examined and desired molecule was produced in relatively higher yields (35~71%,
entries 17ꢀ19) except for the case of AgOTf (no reaction, entry 20). Organic oxidants (BQ, DDQ,
and PhNO2) were much less efficient for CDC (no reaction or trace, entries 21ꢀ23). Under air, the
CDC proceeded to yield 3a in only 11% (entry 24). Finally, we decided to employ inexpensive
Cu(OAc)2 as optimum oxidant for solvent optimizations even though the costly Ag2CO3 gave a
better result in entry 17. Interestingly, it was found that nonpolar xylene or toluene afforded 3a in
moderate yields (61~65%, entries 25ꢀ27), whereas the reaction performed in polar solvents
including DMF, DMAc, DMSO, or NMP was inefficient (18~39%, entries 28ꢀ31).
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Table 1. Facile synthesis of D−π−A type molecules via C−H/C−H coupling:
optimization of reaction conditions.a
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Entry
1
Oxidant
Cu(OAc)2
Cu(OAc)2
Cu(OAc)2
Cu(OAc)2
Cu(OAc)2
Cu(OAc)2
Cu(OAc)2
Cu(OAc)2
Cu(OAc)2
Cu(OAc)2
Cu(OAc)2
Cu(OAc)2
Cu(OAc)2·H2O
Cu(OTf)2
CuCl2
Base
K2CO3
Cs2CO3
K3PO4
Solvent
oꢀxylene
oꢀxylene
oꢀxylene
oꢀxylene
oꢀxylene
oꢀxylene
oꢀxylene
oꢀxylene
oꢀxylene
oꢀxylene
oꢀxylene
oꢀxylene
oꢀxylene
oꢀxylene
oꢀxylene
oꢀxylene
oꢀxylene
oꢀxylene
oꢀxylene
oꢀxylene
oꢀxylene
oꢀxylene
oꢀxylene
oꢀxylene
mꢀxylene
pꢀxylene
toluene
Yieldb
8
2
7
3
4
7
0
0
trace
29
22
0
LiOtBu
KOtBu
Et3N
5
6
7
DBU
8
DABCO
piperidine
TMP
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16
66
57
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0
pyridine
DMAP
pyridine
pyridine
pyridine
pyridine
pyridine
pyridine
pyridine
pyridine
pyridine
pyridine
pyridine
pyridine
pyridine
pyridine
pyridine
pyridine
pyridine
pyridine
pyridine
0
Cu(acac)2
Ag2CO3
10
71
41
35
0
Ag2O
AgOAc
AgOTf
BQ
DDQ
PhNO2
air
Cu(OAc)2
Cu(OAc)2
Cu(OAc)2
Cu(OAc)2
Cu(OAc)2
Cu(OAc)2
Cu(OAc)2
trace
0
trace
11
62
65
61
18
32
27
39
DMF
DMAc
DMSO
NMP
a Reaction conditions: 1a (1.00 mmol), 2a (1.50 mmol), Pd(OAc)2 (0.05 mmol), oxidant (1.50 mmol), and base (1.50
mmol) in solvent (2 mL) at 125 oC for 24 h. b Isolated yields (%).
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Next on, reaction scope with respect to the donor part of dye molecule was investigated using the
optimum reaction conditions obtained in Table 1 (entries 11 and 17: either Cu(OAc)2 or Ag2CO3
was employed as oxidant). Initially, as shown in Table 2, treatment of various triphenylamine
(TPA)ꢀsubstituted thiophene derivatives (1bꢀ1h) with 2ꢀthiophenecarboxaldehyde 2a under
optimum conditions led to the formation of desired D−π−A type products in moderate to good
isolated yields (3bꢀ3h, 52ꢀ70%). Functional groups including thioether, ester, aldehyde, and
pyrroleꢀdione were compatible with current oxidantꢀcontaining reaction conditions. CꢀH/CꢀH
coupling of 2a with TPAꢀsubstituted Nꢀmethylꢀpyrrole (1i) proceeded to yield 3i in 51%. Further,
we also examined a series of carbazoleꢀbased donors such as 1jꢀ1l or 1mꢀ1r, which gave the
corresponding products (3jꢀ3l) in 55ꢀ70% and (3mꢀ3r) in 53ꢀ86% yields. Cyanoꢀ (3g) and ketone
groups (3r) were well tolerated. When phenothiazine was used as donor, target dye molecules were
obtained in moderate yields (3s, 3t; 57%, 65%). Reaction of diphenylaminofluoreneꢀsubstituted
thiophene (1u) with 2a produced 3u in 61% yield. Interestingly, we found
phenyltriazene17ꢀsubstituted thiophene (1v) underwent dehydrogenative coupling smoothly and the
desired product 3v was isolated in 70% yield.
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Table 2. Reaction scope with respect to the donor part:
C-H/C-H coupling of 2a with various donor-type (hetero)aryls 1b-v.a
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a Unless otherwise noted, the CꢀH/CꢀH coupling of 2a (1.50 mmol) with donorꢀtype (hetero)aryls 1b-v
(1.00 mmol) was conducted in the presence of Pd(OAc)2 (5 mol%), Cu(OAc)2 (1.50 mmol), and pyridine
(1.50 mmol) in o
ꢀxylene (2 mL) at 125 oC for 24 h. b Reaction conducted at 100 oC for 12 h and the oxidant
was replaced with Ag2CO3 (1.50 mmol).
In Table 3, reaction scope with respect to the acceptor part was also examined using various
(hetero)aryl aldehydes (2bꢀh). Under optimum reaction conditions, we firstly tested
electronꢀdeficient thiophenes bearing diester group (2b) or a thieno[3,4ꢀc]pyrroleꢀ4,6ꢀdione
(TPD) moiety (2c, 2d) as CꢀH coupling partners, affording the corresponding dye products in
moderate isolated yields (4aꢀ4c, 68ꢀ74%). In addition, when the substrate was changed to
electronꢀrich ethylenedioxythiophene (EDOT), furan, or diesterꢀsubstituted furan, the CꢀH/CꢀH
coupling was shown to proceed smoothly and the terminal acceptor/anchoring groups (nitro,
nitrile, pyrimidine) of desired D−π−A molecules were well tolerated (4dꢀ4f, 55ꢀ92%). Finally,
we found the dehydrogenative coupling between thiophene (donor part) and selenophene
(acceptor part) was inefficient thus leading to a major recovery of both starting materials and a
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poor yield of the desired crossꢀcoupled product (4g, 26%).
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Table 3. Reaction scope with respect to the acceptor part:
C-H/C-H coupling of donor-type (hetero)aryls with various aldehydes 2b-h.a
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a Unless otherwise noted, the CꢀH/CꢀH coupling of donorꢀtype (hetero)aryls (1.00 mmol) with aldehydes
2b-h (1.50 mmol) was conducted in the presence of Pd(OAc)2 (5 mol%), Cu(OAc)2 (1.50 mmol), and
pyridine (1.50 mmol) in
o
ꢀxylene (2 mL) at 125 oC for 24 h.
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In order to carry out photovoltaic applications in dyeꢀsensitized solar cells (DSSCs), we synthesized
three new organic sensitizers (CYL-8~10) based on the optimized CꢀH/CꢀH crossꢀcoupling approach.
As shown in Scheme 2, the crossꢀdehydrogenative coupling reactions were performed smoothly using
different donorꢀ (blue color) and acceptorꢀtype molecules (red color), leading to the formation of the
corresponding aldehydes as precursors of the dye sensitizers (5aꢀ5c, 66ꢀ76%). Generation of the
required anchoring groups by Knoevenagel condensations afforded target dye sensitizers CYL-8~10
in 61ꢀ71% yields (see Experimental Section for the detailed reaction procedures).
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Scheme 2. Facile synthesis of new organic sensitizers CYL-8~10
through direct C-H/C-H cross couplings.
via
C-H/C-H
MeO
O
O
R
S
5a
5b
(R = H): 71%
(R = F): 76%
CHO
N
S
O
O
N
H5C2
C4H9
via
C-H/C-H
F
O
O
F
S
5c: 66%
CHO
N
S
O
O
N
H5C2
C4H9
Ar
5a
5b
5c
CYL-8: 65%
CYL-9: 71%
CYL-10: 61%
cyanoacetic acid
CO2H
piperidine, CHCl3
reflux, 12 h
NC
Subsequently, the UVꢀVis absorption and electrochemical characteristics of CYL-8~10 were
investigated and the obtained results were summarized in Table 4. Compared with CYL-10, in
absorption spectra, CYL-8 and CYL-9 showed more redꢀshifted band and smaller optical bandꢀgap,
owing to their efficient intramolecular charge transfer (ICT) from anisoleꢀsubstituted carbazole (donor)
via thieno[3,4ꢀc]pyrroleꢀ4,6ꢀdione to cyanoacetic acid (acceptor). For all sensitizers, their UVꢀVis
absorption on TiO2 films exhibited blue shifts (compared to the solution state in THF), probably due
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to the coordination/complexation of dye molecules to TiO2. Among three sensitizers, we found that
CYL-9 had the highest molar extinction coefficient (ɛ = 31580 Mꢀ1cmꢀ1), smallest optical bandꢀgap
(Egopt = 1.79 eV), and the lowestꢀlying HOMO/LUMO energy levels (EHOMO = ꢀ5.92 eV/ELUMO = ꢀ4.13
eV). We assumed that these results were resulted from the smooth ICT effect on CYL-9 through
appropriate donorꢀacceptor combination with an additional fluorine atom attached on the acceptor
moiety.
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Table 4. UV-Vis absorption and electrochemical properties of CYL-8~10.
opt
λmax
λmax on TiO2
[nm]a
Eg
E1/2
EHOMO/ELUMO
ε
Dyes
[nm]a
[eV]b
[V]c
[eV]d
[Mꢀ1cmꢀ1]a
CYL-8
CYL-9
CYL-10
460
462
445
12642
31580
19499
439
449
423
1.89
1.79
1.92
1.13
1.22
1.16
ꢀ5.83/ꢀ3.93
ꢀ5.92/ꢀ4.13
ꢀ5.86/ꢀ3.94
a
b
Measured in THF solutions (~10ꢀ5 M); : extinction coefficient. The optical band gap, Egopt, was calculated by
ε
c
1240/λonset (dyes on TiO2 films). The halfꢀwave potential, E1/2, was calculated by (Epa+Epc)/2, where Epa and Epc are the
potential energy of anodic and cathodic peaks, respectively; The measurements are conducted in THF solutions (~10ꢀ4 M)
d
containing (nꢀC4H9)4NPF6 as a supporting electrolyte under a scan rate of 100 mVsꢀ1. The HOMO energy level, EHOMO
,
opt
was calculated by –[(E1/2 + 0.197)vs.NHE + 4.500] eV; ELUMO = EHOMO + Eg
.
Dyeꢀsensitized solar cells (DSSCs) were fabricated employing CYL-8~10 as sensitizers and the
photovoltaic parameters were collected in Table 5 and illustrated in Figure 1 (fabrication procedures
and characterization of solar cells were detailed in Experimental Section). Although CYL-9 appeared
to generate efficient intramolecular charge transfer, as discussed in Table 4, it exhibited relatively
lower shortꢀcircuit photocurrent density (Jsc = 6.52 mA/cm2), thus leading to an inferior power
conversion efficiency (PCE) of 3.00%. We speculated that this was owing to the resistant charge
transport from the LUMO of CYL-9 to TiO2 (CYL-9 LUMO = −4.13 eV, lower than the energy level
of TiO2 = −4.00 eV). In addition, we found CYL-8 and CYL-10 displayed similar incident
photonꢀtoꢀcurrent conversion efficiency (IPCE, Figure 1b) in the absorption range of 400−500 nm.
Between 500−700 nm, CYL-8 showed stronger IPCE absorption, leading to a higher Jsc
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Table 5. Photovoltaic performances of DSSCs fabricated using
CYL-8, CYL-9, and CYL-10.a, b
Voc [V]
0.68
Jsc [mA/cm2]
9.81
FF [%]
72.7
PCE [%]
4.85
5
6
7
8
DSSCs
CYL-8
CYL-9
CYL-10
9
0.63
6.52
73.0
3.00
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0.62
7.54
72.5
3.39
Z907c
0.69
14.75
69.5
7.07
Irradiation light source: AM 1.5G solar simulator (100 mW/cm2); Photoꢀelectrode (working electrode): TiO2 film was
a
composed of 16 ꢁm thick mesoporous anataseꢀTiO2 nanoparticles with a diameter of 20 nm and has an active area of 0.160
cm2; Electrolyte solution: a mixture of 0.6 M 1ꢀbutylꢀ3ꢀmethylimidazolium iodide ([bmim][I]), 0.1 M LiI, 0.05 M I2, 0.1
M guanidinium thiocyanate (GuNCS) and 0.5 M 4ꢀtꢀbutylpyridine (TBP) in acetonitrile. b Chenodeoxycholic acid (CDCA)
c
was added as coꢀadsorbent (5 mM for CYL-9; no CDCA was added for CYL-8
& CYL-10).
cisꢀBis(isothiocyanato)(2,2’ꢀbipyridylꢀ4,4’ꢀdicarboxylato)(4,4’ꢀdiꢀnonylꢀ2’ꢀbipyridyl)ruthenium(II).
Figure 1. Photovoltaic performances of CYL-8, CYL-9, and CYL-10: (a) photocurrent density
vs. photovoltage; (b) Incident photon-to-current conversion efficiency (IPCE); (c)
electrochemical impedance spectroscopy (EIS).
(a)
(b)
(c)
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of 9.81 mA/cm2. It was noted that CYL-8~10 possessed similar openꢀcircuit voltage (Voc) because
they had been shown to exhibit similar charge transfer impedance under dark conditions (Nyquist
plots, Figure 1c). Besides, addition of the chenodeoxycholic acid (CDCA) as coꢀadsorbent may
influence the the amount of dyes adsorbed on TiO2. In the case of CYL-9, the optimum PCE was
observed when 5 mM of CDCA was added. Presumably the dye aggregation of CYL-9 was
reduced/broken by CDCA. On the contrary, in the cases of CYL-8 and CYL-10, we found the best
PCE could be only obtained under CDCAꢀfree condition because CDCA may have adsorption
competition with the dyes on TiO2, thus lowing the dye adsorption amount. Finally, among three new
sensitizers, CYL-8 demonstrated a Voc of 0.68 V, a Jsc of 9.81 mA/cm2, and a fill factor (FF) of 72.7%,
corresponding to the highest power conversion efficiency of 4.85 %.
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Conclusion
We have demonstrated a highly atomꢀeconomical alternative route to various D−π−A type
organic dyes via direct CꢀH/CꢀH crossꢀcouplings. Under optimized synthetic conditions, a wide
range of substrate scope was successfully explored along with excellent functional groups
compatibility. For photovoltaic applications, we efficiently synthesized three new organic
sensitizers (CYL-8~10) that were fabricated as dyeꢀsensitized solar cells (DSSCs), showing the
power conversion efficiency (PCE) up to 4.85%. Currently, development of
atom/stepꢀeconomical green catalysis reactions for organic photovoltaic materials is underway in
our laboratory.
Experimental Section
General information: Unless otherwise specified, all reactions were carried out with magnetic
stirring and in flameꢀdried glassware under nitrogen if air or moisture sensitive. Reagents
including Pd(OAc)2, oxidants, and bases are commercially available. Anhydrous or reagentꢀgrade
solvents such as oꢀ, mꢀ, pꢀxylene, toluene, N, Nꢀdimethylformamide (DMF), dimethyl sulfoxide
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8
(DMSO), and Nꢀmethylꢀ2ꢀpyrrolidone (NMP) were purchased from SigmaꢀAldrich, Acros, or
Alfa Aesar and used directly without further purifications. Syringes used to transfer reagents and
solvents were purged with nitrogen prior to use. Reactions were monitored by thin layer
chromatography (TLC, aluminum plates coated with silica gel, Merck 60, Fꢀ254). The spots were
visualized by UV light. Flash column chromatography was performed using silica gel 60
(spherical, 63ꢀ210 ꢁm) from Merck. The diameters of the columns and the amount of silica gel
loaded were calculated according to the recommendation of W. C. Still.18 Melting points were
measured on a Fargo MPꢀ2D apparatus. NMR spectra were recorded on a Bruker Magnet System
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1
300 or 500 MHz instrument. Chemical shifts were given relative to CDCl3 (7.26 ppm for H
1
NMR, 77.0 ppm for 13C NMR), CD2Cl2 (5.32 ppm for H NMR, 54.0 ppm for 13C NMR),
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DMSOꢀd6 (2.50 ppm for H NMR, 39.4 ppm for C NMR), acetoneꢀd6 (2.04 ppm for H NMR,
29.3 ppm for 13C NMR). For the characterization of the observed signal multiplicities, the
following abbreviations were applied: s (singlet), d (doublet), dd (doublet of doublets), dt (doublet
of triplets), dm (doublet of multiplets), t (triplet), td (triplet of doublets), q (quartet), quint
(quintet), m (multiplet), comp (complex), app (apparent), and br (broad). Mass spectra were
recorded on a JEOL JMSꢀ700 for electron impact ionization (EI) and high resolution mass spectra
(HRMS) on a JEOL JMSꢀ700 spectrometers. Fast atom bombardment (FAB) samples were
recorded in a 3ꢀnitrobenzyl alcoholꢀ or glycerineꢀmatrix. Absorption spectra were measured on a
Hitachi Uꢀ4100 UVꢀVis spectrophotometer, and the HOMOꢀLUMO optical band gap (Egopt) was
calculated according to the λonset obtained. The experiments of cyclic voltammetry were carried
out with an Autolab electrochemical analyzer using a Pt working electrode, a Pt wire counter
electrode, and a Ag/AgCl reference electrode. The measurements were conducted in dry THF
solution containing 0.1 M tetraꢀnꢀbutylammonium hexafluorophosphate as a supporting
electrolyte under a scan rate of 100 mVsꢀ1. The halfꢀwave potential, E1/2, was calculated by
(Epa+Epc)/2, where Epa and Epc are the potential energy of anodic and cathodic peaks, respectively.
The HOMO energy level, EHOMO, was calculated by ꢀ(E1/2 + 0.197 + 4.500) eV (vs. Ag/AgCl and
opt
NHE); ELUMO = EHOMO + Eg
.
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Procedures for the fabrication and performance characterization of dyeꢀsensitized solar cells
(DSSCs): The DSSCs were fabricated using CYL-8, CYL-9, or CYL-10 as sensitizers. The TiO2
paste and TiO2 film were prepared according to the methods described in the literature.19
Photoꢀelectrode (working electrode): TiO2 screen printing was carried out on a piece of
fluorineꢀdoped tin oxide glass (FTO, sheet resistivity of 7 ꢂ/square). The TiO2 film was
composed of 16 ꢁm thick mesoporous anataseꢀTiO2 nanoparticles with a diameter of 20 nm and a
4 ꢁm thick TiO2 scattering layer with a diameter of 400 nm. After sintered at 350 °C for 15 mins
and at 500 °C for 30 mins, the TiO2 photoꢀelectrode that has an active area of 0.160 cm2 was
immersed in the freshly prepared dye solution (anhydrous THF or CHCl3) at 40 °C for 24 hours.
Counter electrode: another piece FTO glass coated with Pt was used as counter electrode. The
electrolyte solution was prepared via mixing 0.6 M 1ꢀbutylꢀ3ꢀmethylimidazolium iodide
([bmim][I]), 0.1 M LiI, 0.05 M I2, 0.1 M GuNCS, and 0.5 M 4ꢀtꢀbutylpyridine (TBP) in
acetonitrile. To the dye solution containing 2.0 x 10ꢀ4 M of CYL-8, CYL-9, or CYL-10 in THF,
chenodeoxycholic acid (CDCA, 1.0~10 mM in anhydrous THF) was added as coꢀadsorbent to see
if the performance of DSSCs was improved (A CDCAꢀfree dye solution was also prepared for the
comparative experiment during the optimization of device performance of DSSCs).
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An IPCE spectrometer (EQEꢀRꢀ3011, ENLI Technology Co. Ltd., Taiwan) calibrated with a
singleꢀcrystal silicon reference cell for each measurement was used for the incident
monochromatic photonꢀtoꢀcurrent conversion efficiency (IPCE) measurements. An AM 1.5G
solar simulator (Yamashita Denso Corporation, YSSꢀ50A) was used as the irradiation light source
for the characteristic current densityꢀvoltage (JꢀV) measurements. The intensity of the simulated
sunlight was calibrated to 100 mW/cm2. The JꢀV characteristics of the cell under an illumination
of AM 1.5G simulated sunlight were obtained by applying the external potential bias to the cell
and measuring the photocurrent output with a Keithley model 2400 digital source meter (Keithley,
USA).
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The Journal of Organic Chemistry
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General procedure A for the starting materials synthesis: C-H/C-Br coupling reactions
To a solution of Pd(OAc)2 (0.05 mmol), ligand (0.10 mmol), PivOH (0.30 mmol), and K2CO3
(1.50 mmol) in DMF or toluene (3 mL) in a flameꢀdried Schlenk tube (20 mL) were added the
corresponding (hetero)arene (2.00ꢀ5.00 mmol) and aryl bromide (1.00 mmol) under N2. The
reaction mixture was then heated at 110 °C under N2 for 12 h. After the reaction mixture had
cooled to room temperature, water (10 mL) was added. The mixture was extracted with ethyl
acetate (2 × 30 mL), and the combined organic layers were washed with brine (50 mL), dried
(Na2SO4) and concentrated in vacuo. Purification by flash chromatography yielded the desired
starting materials 1e-1w.
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4-(Dodecylthio)-N-(4-(dodecylthio)phenyl)-N-(4-(thiophen-2-yl)phenyl)aniline
(1e)
was
prepared from 4ꢀbromoꢀN,Nꢀbis(4ꢀ(dodecylthio)phenyl)aniline20 (725 mg, 1.00 mmol), thiophene
(420 mg, 5.00 mmol), Pd(OAc)2 (12 mg, 0.05 mmol), PPh3 (26 mg, 0.10 mmol), PivOH (31 mg,
0.30 mmol), K2CO3 (207 mg, 1.50 mmol), and DMF (3 mL) according to the general procedure A
and yielding after column chromatography (dichloromethane : hexanes = 20 : 80) the pure
product 1e (328 mg, 45 %). Colorless viscous liquid. 1H NMR (CDCl3, 300 MHz, ppm): δ 7.52 (d,
J = 8.4 Hz, 2 H), 7.19ꢀ7.42 (comp, 6 H), 6.87ꢀ7.18 (comp, 7 H), 2.93 (t, J = 7.4 Hz, 4 H),
1.59ꢀ1.81 (comp, 4 H), 1.18ꢀ1.55 (comp, 36 H), 0.82ꢀ0.99 (comp, 6 H); 13C NMR (CDCl3, 75
MHz, ppm): δ 146.7, 145.5, 144.1, 130.8, 130.7, 129.0, 128.0, 126.8, 124.7, 124.2, 123.9, 122.4,
34.6, 32.0, 29.8, 29.7, 29.6, 29.5, 29.4, 29.3, 28.9, 22.8, 14.2; MS (FAB): 728 ([M+H]+, 86 %),
527 (39 %), 55 (100 %); HRMS (FAB/Double Focusing) m/z: [M+H]+ Calcd. for C46H65NS3
727.4279; found 727.4275.
2-(4-(Diphenylamino)phenyl)thiophene-3,4-dicarbaldehyde (1g) was prepared from
4ꢀbromotriphenylamine (324 mg, 1.00 mmol), thiopheneꢀ3,4ꢀdicarbaldehyde (280 mg, 2.00
mmol), Pd(OAc)2 (12 mg, 0.05 mmol), PCy3 (28 mg, 0.10 mmol), PivOH (31 mg, 0.30 mmol),
K2CO3 (207 mg, 1.50 mmol), and toluene (3 mL) according to the general procedure A and
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1
2
yielding after column chromatography (ethyl acetate : hexanes = 10 : 90) the pure product 1g (211
3
4
o
mg, 55 %). Yellow solid; m.p.: 176.2.ꢀ176.6 C. 1H NMR (CDCl3, 300 MHz, ppm): δ 10.49 (s, 1
5
6
7
8
H), 10.04 (s, 1 H), 8.09 (s, 1 H), 7.28ꢀ7.39 (comp, 5 H), 6.97ꢀ7.21 (comp, 9 H); 13C NMR (CDCl3,
75 MHz, ppm): δ 187.2, 187.0, 159.6, 149.8, 146.8, 141.2, 133.6, 131.4, 131.0, 129.7, 125.5,
124.3, 123.1, 121.5; MS (EI, 70 eV): 383 (M+, 8 %), 167 (20 %), 77 (100 %); HRMS (EI/Double
Focusing) m/z: M+ Calcd. for C24H17NO2S 383.0980; found 383.0974.
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5-(2-Ethylhexyl)-1-(9-hexyl-9H-carbazol-3-yl)-4H-thieno[3,4-c]pyrrole-4,6(5H)-dione
was prepared from 3ꢀbromoꢀ9ꢀhexylꢀ9Hꢀcarbazole (330 mg, 1.00
(1n)
mmol),
5ꢀ(2ꢀethylhexyl)ꢀ4Hꢀthieno[3,4ꢀc]pyrroleꢀ4,6(5H)ꢀdione (398 mg, 1.50 mmol), Pd(OAc)2 (12 mg,
0.05 mmol), PCy3 (28 mg, 0.10 mmol), PivOH (31 mg, 0.30 mmol), K2CO3 (207 mg, 1.50 mmol),
and toluene (3 mL) according to the general procedure A and yielding after column
chromatography (dichloromethane : hexanes = 50 : 50) the pure product 1n (308 mg, 60 %). Red
o
1
solid; m.p.: 84.5ꢀ85.0 C. H NMR (CDCl3, 300 MHz, ppm): δ 8.80 (s, 1 H), 8.19 (app t, 2 H),
7.43ꢀ7.68 (comp, 2 H), 7.18ꢀ7.43 (comp, 3 H), 4.18 (t, J = 7.0 Hz, 2 H), 3.55 (d, J = 6.9 Hz, 2 H),
1.70ꢀ1.98 (comp, 3 H), 1.18ꢀ1.57 (comp, 14 H), 0.74ꢀ1.14 (comp, 9 H); 13C NMR (CDCl3, 75
MHz, ppm): δ 163.7, 163.0, 149.8, 141.3, 141.0, 137.9, 126.8, 126.3, 125.9, 123.1, 122.8, 121.8,
121.7, 120.8, 120.3, 119.6, 109.1, 108.9, 43.2, 42.4, 38.2, 31.6, 30.6, 28.9, 28.6, 26.9, 23.9, 23.1,
22.6, 14.2, 14.0, 10.5; MS (FAB): 514 (M+, 100 %), 443 (48 %), 415 (32 %); HRMS (EI/Double
Focusing) m/z: M+ Calcd. for C32H38N2O2S 514.2654; found 514.2648.
9-(4-(Methylthio)phenyl)-3-(thiophen-2-yl)-9H-carbazole
(1o)
was
prepared
from
3ꢀbromoꢀ9ꢀ(4ꢀ(methylthio)phenyl)ꢀ9Hꢀcarbazole (368 mg, 1.00 mmol), thiophene (420 mg, 5.00
mmol), Pd(OAc)2 (12 mg, 0.05 mmol), P(adamantyl)2(nꢀBu) (36 mg, 0.10 mmol), PivOH (31 mg,
0.30 mmol), K2CO3 (207 mg, 1.50 mmol), and DMF (3 mL) according to the general procedure A
and yielding after column chromatography (ethyl acetate : hexanes = 5 : 95) the pure product 1o
1
(186 mg, 50 %). Transparent viscous liquid. H NMR (CDCl3, 300 MHz, ppm): δ 8.46 (app s, 1
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H), 8.25 (d, J = 7.2 Hz, 1 H), 7.72 (d, J = 8.7 Hz, 1 H), 7.28ꢀ7.52 (comp, 10 H), 7.10ꢀ7.22 (m, 1
H), 2.60 (s, 3 H); 13C NMR (CDCl3, 75 MHz, ppm): δ 145.6, 141.4, 140.4, 138.2, 134.4, 128.2,
127.7, 127.5, 126.9, 126.5, 124.7, 124.0, 123.9, 123.4, 122.4, 120.7, 120.4, 117.9, 110.2, 110.0,
15.9; MS (EI, 70 eV): 371 (M+, 2 %), 177 (6 %), 133 (16 %), 63 (100 %); HRMS (EI/Double
Focusing) m/z: [M+H]+ Calcd. for C23H17NS2 371.0802; found 371.0810.
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9-(4-Fluorophenyl)-3-(thiophen-2-yl)-9H-carbazole
(1p)
was
prepared
from
3ꢀbromoꢀ9ꢀ(4ꢀfluorophenyl)ꢀ9Hꢀcarbazole (340 mg, 1.00 mmol), thiophene (420 mg, 5.00 mmol),
Pd(OAc)2 (12 mg, 0.05 mmol), PPh3 (26 mg, 0.10 mmol), PivOH (31 mg, 0.30 mmol), K2CO3
(207 mg, 1.50 mmol), and DMF (3 mL) according to the general procedure A and yielding after
1
column chromatography (hexanes) the pure product 1p (154 mg, 45 %). Pale green liquid. H
NMR (CDCl3, 300 MHz, ppm): δ 8.52 (app s, 1 H), 8.31 (d, J = 7.8 Hz, 1 H), 7.78 (d, J = 8.4 Hz,
1 H), 7.10ꢀ7.70 (comp, 11 H); 13C NMR (CDCl3, 75 MHz, ppm): δ 161.8 (d, JCꢀF = 245.9 Hz),
1
145.6, 141.6, 140.6, 133.5 (d, 4JCꢀF = 2.8 Hz), 129.0 (d, 3JCꢀF = 8.5 Hz), 128.3, 127.1, 126.6, 124.8,
2
124.1, 124.0, 123.4, 122.5, 120.8, 120.5, 118.0, 117.0 (d, JCꢀF = 22.6 Hz), 110.0, 109.9; MS (EI,
70 eV): 343 (M+, 100 %), 156 (18 %), 141 (20 %); HRMS (EI/Double Focusing) m/z: M+ Calcd.
for C22H14FNS 343.0831; found 343.0827.
4-(3-(Thiophen-2-yl)-9H-carbazol-9-yl)benzonitrile
(1q)
was
prepared
from
4ꢀ(3ꢀbromoꢀ9Hꢀcarbazolꢀ9ꢀyl)benzonitrile (347 mg, 1.00 mmol), thiophene (420 mg, 5.00 mmol),
Pd(OAc)2 (12 mg, 0.05 mmol), PPh3 (26 mg, 0.10 mmol), PivOH (31 mg, 0.30 mmol), K2CO3
(207 mg, 1.50 mmol), and DMF (3 mL) according to the general procedure A and yielding after
column chromatography (ethyl acetate : hexanes = 5 : 95) the pure product 1q (179 mg, 51 %).
White solid; m.p.: 193.9ꢀ194.8 oC. 1H NMR (CDCl3, 300 MHz, ppm): δ 8.34 (d, J = 1.5 Hz, 1 H),
8.17 (d, J = 7.5 Hz, 1 H), 7.87ꢀ7.98 (comp, 2 H), 7.58ꢀ7.78 (comp, 3 H), 7.26ꢀ7.55 (comp, 6 H),
7.15 (dd, J = 5.1, 3.6 Hz, 1 H); 13C NMR (CDCl3, 75 MHz, ppm): δ 145.0, 141.7, 140.3, 139.2,
134.0, 128.2, 127.8, 126.9, 126.8, 124.8, 124.5, 124.3, 123.9, 122.6, 121.3, 120.8, 118.5, 117.9,
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110.5, 110.0, 109.8; MS (EI, 70 eV): 350 (M+, 41 %), 248 (17 %), 102 (100 %); HRMS
(EI/Double Focusing) m/z: M+ Calcd. for C23H14N2S 350.0878; found 350.0884.
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Phenyl(4-(3-(thiophen-2-yl)-9H-carbazol-9-yl)phenyl)methanone (1r) was prepared from
(4ꢀ(3ꢀbromoꢀ9Hꢀcarbazolꢀ9ꢀyl)phenyl)(phenyl)methanone (426 mg, 1.00 mmol), thiophene (420
mg, 5.00 mmol), Pd(OAc)2 (12 mg, 0.05 mmol), PPh3 (26 mg, 0.10 mmol), PivOH (31 mg, 0.30
mmol), K2CO3 (207 mg, 1.50 mmol), and DMF (3 mL) according to the general procedure A and
yielding after column chromatography (ethyl acetate : hexanes = 5 : 95) the pure product 1r (258
mg, 60 %). Pale green solid; m.p.: 180.0ꢀ181.2 oC. 1H NMR (CDCl3, 300 MHz, ppm): δ 8.35ꢀ8.48
(m, 1 H), 8.20 (d, J = 7.2 Hz, 1 H), 8.10 (d, J = 8.4 Hz, 2 H), 8.04ꢀ8.87 (comp, 2 H), 7.66ꢀ7.78
(comp, 4 H), 7.46ꢀ7.65 (comp, 5 H), 7.27ꢀ7.44 (comp, 3 H), 7.10ꢀ7.22 (m, 1 H); 13C NMR
(CDCl3, 75 MHz, ppm): δ 195.6, 145.3, 141.4, 140.7, 139.7, 137.4, 136.0, 132.8, 132.0, 130.2,
128.6, 128.2, 127.5, 126.7, 126.1, 124.8, 124.1, 123.8, 122.5, 120.9, 120.7, 117.9, 110.2, 110.1;
MS (EI, 70 eV): 430 ([M+1]+, 100 %), 348 (32 %), 84 (75 %); HRMS (EI/Double Focusing) m/z:
M+ Calcd. for C29H19NOS 429.1187; found: 429.1181.
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Ethyl 4-(3-(thiophen-2-yl)-10H-phenothiazin-10-yl)benzoate (1t) was prepared from ethyl
4ꢀ(3ꢀbromoꢀ10Hꢀphenothiazinꢀ10ꢀyl)benzoate (426 mg, 1.00 mmol), thiophene (420 mg, 5.00
mmol), Pd(OAc)2 (12 mg, 0.05 mmol), PCy3 (28 mg, 0.10 mmol), PivOH (31 mg, 0.30 mmol),
K2CO3 (207 mg, 1.50 mmol), and DMF (3 mL) according to the general procedure A and yielding
after column chromatography (ethyl acetate : hexanes = 2 : 98) the pure product 1t (176 mg, 41
1
%). Transparent viscous liquid. H NMR (CDCl3, 300 MHz, ppm): δ 8.20 (d, J = 7.5 Hz, 2 H),
7.47 (s, 1 H), 7.35 (d, J = 7.5 Hz, 2 H), 6.92ꢀ7.32 (comp, 7 H), 6.38ꢀ6.90 (comp, 2 H), 4.46 (q, J =
7.0 Hz, 2 H), 1.47 (t, J = 7.0 Hz, 3 H); 13C NMR (CDCl3, 75 MHz, ppm): δ 165.9, 146.7, 143.0,
142.6, 142.0, 131.9, 130.6, 128.2, 127.8, 127.6, 127.2, 126.3, 125.2, 124.8, 124.7, 124.6, 124.3,
123.0, 120.3, 120.2, 61.1, 14.6; MS (EI, 70 eV): 429 (M+, 12 %), 239 (15 %), 84 (96 %), 57 (100
%); HRMS (EI/Double Focusing) m/z: M+ Calcd. for C25H19NO2S2 429.0857; found 429.0861.
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The Journal of Organic Chemistry
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(E)-1-((4-(Thiophen-2-yl)phenyl)diazenyl)pyrrolidine
(1v)
was
prepared
from
5
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7
8
(E)ꢀ1ꢀ((4ꢀbromophenyl)diazenyl)pyrrolidine21 (254 mg, 1.00 mmol), thiophene (420 mg, 5.00
mmol), Pd(OAc)2 (12 mg, 0.05 mmol), PPh3 (26 mg, 0.10 mmol), PivOH (31 mg, 0.30 mmol),
K2CO3 (207 mg, 1.50 mmol), and DMF (3 mL) according to the general procedure A and yielding
after column chromatography (ethyl acetate : hexanes = 5 : 95) the pure product 1v (162 mg, 63
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60
1
%). Transparent viscous liquid. H NMR (CDCl3, 300 MHz, ppm): δ 7.69 (d, J = 8.7 Hz, 2 H),
7.56 (d, J = 8.7 Hz, 2 H), 7.36 (dd, J = 3.6, 0.9 Hz, 1 H), 7.30 (dd, J = 5.1, 0.9 Hz, 1 H), 7.12 (dd,
J = 5.1, 3.6 Hz, 1 H), 3.84 (app s, 4 H), 2.01 (t, J = 6.6 Hz, 4 H); 13C NMR (CDCl3, 75 MHz,
ppm): δ 150.9, 144.7, 131.2, 128.2, 126.5, 124.3, 122.5, 120.9, 23.9; MS (EI, 70 eV): 257 (M+, 17
%), 159 (48 %), 84 (100 %); HRMS (EI/Double Focusing) m/z: M+ Calcd. for C14H15N3S
257.0987; found 257.0981.
3-(2,3-Dihydrothieno[3,4-b][1,4]dioxin-5-yl)-9-(4-fluorophenyl)-9H-carbazole
(1w)
was
prepared from 9ꢀ(4ꢀfluorophenyl)ꢀ9Hꢀcarbazole (261 mg, 1.00 mmol), EDOT (710 mg, 5.00
mmol), Pd(OAc)2 (12 mg, 0.05 mmol), PPh3 (26 mg, 0.10 mmol), PivOH (31 mg, 0.30 mmol),
K2CO3 (207 mg, 1.50 mmol), and DMF (3 mL) according to the general procedure A and yielding
after column chromatography (ethyl acetate : hexanes = 2 : 98) the pure product 1w (173 mg, 43
%). Light green viscous liquid. 1H NMR (CDCl3, 500 MHz, ppm): δ 8.72 (app s, 1 H), 8.36 (d, J
= 8.0 Hz, 1 H), 7.95 (d, J = 8.5 Hz, 1 H), 7.51ꢀ7.66 (comp, 3 H), 7.42ꢀ7.51 (comp, 3 H), 7.33ꢀ7.41
(comp, 2 H), 6.45 (s, 1 H), 4.35ꢀ4.41 (comp, 2 H), 4.27ꢀ4.33 (comp, 2 H); 13C NMR (CDCl3, 125
MHz, ppm): δ 161.7 (d, 1JCꢀF = 246.3 Hz), 142.6, 141.5, 140.0, 137.5, 133.7, 129.0 (d, 3JCꢀF = 7.5
2
Hz), 126.5, 125.8, 125.1, 123.8, 123.6, 120.8, 120.4, 118.6, 118.3, 117.0 (d, JCꢀF = 22.5 Hz),
109.9, 96.8, 64.9, 64.6; MS (EI, 70 eV): 401 (M+, 55 %), 304 (40 %), 191 (38 %), 84 (100 %);
HRMS (EI/Double Focusing) m/z: M+ Calcd. for C24H16FNO2S 401.0886; found 401.0885.
General procedure B for Table 1: Optimization of the C-H/C-H coupling reaction between N,
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1
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N-diphenyl-4-(thiophen-2-yl)aniline (1a) and thiophene-2-carbaldehyde (2a)
3
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6
7
8
9
To a solution of Pd(OAc)2 (0.05 mmol), oxidant (1.50 mmol), and base (1.50 mmol) in solvent (2
mL) in a flameꢀdried Schlenk tube were added N, Nꢀdiphenylꢀ4ꢀ(thiophenꢀ2ꢀyl)aniline (1a) (1.00
mmol) and thiopheneꢀ2ꢀcarbaldehyde (2a) (1.50 mmol) under N2. The reaction mixture was then
heated at 130 °C under N2 for 24 h. After the reaction mixture had cooled to room temperature,
water (10 mL) was added. The mixture was extracted with ethyl acetate (2 × 20 mL), and the
combined organic layers were washed with brine (50 mL), dried (Na2SO4) and concentrated in
vacuo. Purification by flash chromatography yielded the desired product 3a.
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5'-(4-(Diphenylamino)phenyl)-[2,2'-bithiophene]-5-carbaldehyde22 (3a) was prepared from
1a23a (327 mg, 1.00 mmol), 2a (168 mg, 1.50 mmol), Pd(OAc)2 (12 mg, 0.05 mmol), Cu(OAc)2
(273 mg, 1.50 mmol), pyridine (119 mg, 1.50 mmol), and oꢀxylene (2 mL) according to the
general procedure B and yielding after column chromatography (dichloromethane : hexanes = 40 :
o
1
60) the pure product 3a (289 mg, 66 %). Orange solid; m.p.: 150.0ꢀ150.4 C. H NMR (CDCl3,
300 MHz, ppm): δ 9.86 (s, 1 H), 7.67 (d, J = 3.9 Hz, 1 H), 7.43ꢀ7.55 (comp, 2 H), 7.27ꢀ7.40
(comp, 5 H), 7.25 (d, J = 3.9 Hz, 1 H), 7.00ꢀ7.23 (comp, 9 H); 13C NMR (CDCl3, 75 MHz, ppm):
δ 182.4, 148.1, 147.4, 147.3, 146.3, 141.3, 137.5, 134.1, 129.5, 127.3, 127.1, 126.7, 124.9,
123.8, 123.5, 123.2, 123.1.
General procedure C for Table 2 & Table 3: Substrate scope of the heteroarenes
To a solution of Pd(OAc)2 (0.05 mmol), Cu(OAc)2 or Ag2CO3 (1.50 mmol), and pyridine (1.50
mmol) in oꢀxylene (2 mL) in a flameꢀdried Schlenk tube were added the heteroarene (1b-w) (1.00
mmol) and the aldehydeꢀcontaining heteroarene (2a-h) (1.50 mmol) under N2. The reaction
mixture was then heated at 100~130 °C under N2 for 12~24 h. After the reaction mixture had
cooled to room temperature, water (10 mL) was added. The mixture was extracted with ethyl
acetate (2 × 20 mL), and the combined organic layers were washed with brine (50 mL), dried
(Na2SO4) and concentrated in vacuo. Purification by flash chromatography yielded the desired
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The Journal of Organic Chemistry
1
2
products 3b-v and 4aꢀg.
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5'-(4-((4-Dodecylphenyl)(phenyl)amino)phenyl)-[2,2'-bithiophene]-5-carbaldehyde (3b) was
prepared from 1b23a (496 mg, 1.00 mmol), 2a (168 mg, 1.50 mmol), Pd(OAc)2 (12 mg, 0.05
mmol), Cu(OAc)2 (273 mg, 1.50 mmol), pyridine (119 mg, 1.50 mmol), and oꢀxylene (2 mL)
according to the general procedure C and yielding after column chromatography
(dichloromethane : hexanes = 60 : 40) the pure product 3b (369 mg, 61 %). Golden yellow solid;
m.p.: 104.3ꢀ104.9 oC. 1H NMR (CDCl3, 300 MHz, ppm): δ 9.85 (s, 1 H), 7.65 (d, J = 3.9 Hz, 1 H),
7.44 (d, J = 8.7 Hz, 2 H), 7.24ꢀ7.35 (comp, 3 H), 7.22 (d, J = 3.9 Hz, 1 H), 6.98ꢀ7.19 (comp, 10
H), 2.60 (t, J = 7.8 Hz, 2 H), 1.57ꢀ1.72 (comp, 2 H), 1.21ꢀ1.48 (comp, 18 H), 0.91 (t, J = 6.6 Hz, 3
H); 13C NMR (CDCl3, 75 MHz, ppm): δ 182.3, 148.3, 147.5, 147.4, 146.4, 144.7, 141.2, 138.7,
137.5, 133.9, 129.5, 129.4, 127.3, 126.64, 126.57, 125.3, 124.5, 123.7, 123.2, 123.1, 122.6, 35.5,
32.0, 31.6, 29.8 (two peaks), 29.7 (two peaks), 29.6, 29.52, 29.48, 22.8, 14.3; MS (EI, 70 eV):
606 ([M+H]+, 3 %), 472 (100 %), 457 (73 %); HRMS (EI/Double Focusing) m/z: M+ Calcd. for
C39H43NOS2 605.2786; found 605.2776.
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5'-(4-((4-(2-Ethylhexyl)phenyl)(phenyl)amino)phenyl)-[2,2'-bithiophene]-5-carbaldehyde (3c)
was prepared from 1c23a (440 mg, 1.00 mmol), 2a (168 mg, 1.50 mmol), Pd(OAc)2 (12 mg, 0.05
mmol), Cu(OAc)2 (273 mg, 1.50 mmol), pyridine (119 mg, 1.50 mmol), and oꢀxylene (2 mL)
according to the general procedure C and yielding after column chromatography
(dichloromethane : hexanes = 60 : 40) the pure product 3c (296 mg, 54 %). Orange solid; m.p.:
o
1
88.3ꢀ89.0 C. H NMR (CDCl3, 300 MHz, ppm): δ 9.87 (s, 1 H), 7.67 (d, J = 3.9 Hz, 1 H),
7.43ꢀ7.56 (comp, 2 H), 7.26ꢀ7.36 (comp, 3 H), 7.24 (d, J = 4.2 Hz, 1 H), 7.00ꢀ7.22 (comp, 10 H),
2.54 (d, J = 6.9 Hz, 2 H), 1.52ꢀ1.65 (m, 1 H), 1.23ꢀ1.44 (comp, 8 H), 0.93 (app t, J = 7.2 Hz, 6 H);
13C NMR (CDCl3, 75 MHz, ppm): δ 182.4, 148.3, 147.5, 147.4, 146.4, 144.7, 141.2, 137.6,
137.5, 133.9, 130.2, 129.4, 127.3, 126.63, 126.57, 125.1, 124.5, 123.7, 123.2, 123.1, 122.6, 41.1,
39.6, 32.4, 28.9, 25.6, 23.1, 14.2, 10.9; MS (EI, 70 eV): 550 ([M+H]+, 75 %), 451 (51 %), 84 (100
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%); HRMS (EI/Double Focusing) m/z: M+ Calcd. for C35H35NOS2 549.2160; found 549.2166.
1
2
3
4
5
6
7
8
5'-(4-(Bis(4-methoxyphenyl)amino)phenyl)-[2,2'-bithiophene]-5-carbaldehyde (3d) was
prepared from 4ꢀmethoxyꢀNꢀ(4ꢀmethoxyphenyl)ꢀNꢀ(4ꢀ(thiophenꢀ2ꢀyl)phenyl)aniline24 (1d) (387
mg, 1.00 mmol), 2a (336 mg, 3.00 mmol), Pd(OAc)2 (12 mg, 0.05 mmol), Ag2CO3 (413 mg, 1.50
mmol), pyridine (119 mg, 1.50 mmol), and oꢀxylene (2 mL) according to the general procedure C
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60
o
(100 C, 12 h for this example) and yielding after column chromatography (using the eluent with
a gradient polarity: from dichloromethane : hexanes = 40 : 60 to dichloromethane : hexanes = 80 :
o
1
20) the pure product 3d (348 mg, 70 %). Red solid; m.p.: 205.3ꢀ205.8 C. H NMR (CDCl3, 300
MHz, ppm): δ 9.83 (s, 1 H), 7.64 (d, J = 4.2 Hz, 1 H), 7.39 (d, J = 8.7 Hz, 2 H), 7.29 (d, J = 3.9
Hz, 1 H), 7.21 (d, J = 4.2 Hz, 1 H), 7.02ꢀ7.15 (comp, 5 H), 6.79ꢀ6.95 (comp, 6 H), 3.81 (s, 6 H);
13C NMR (CDCl3, 75 MHz, ppm): δ 182.4, 156.3, 149.0, 147.6, 146.7, 141.1, 140.3, 137.6, 133.5,
127.3, 127.0, 126.5, 125.1, 123.6, 122.7, 120.0, 114.8, 55.5; MS (EI, 70 eV): 498 ([M+H]+, 52 %),
395 (38 %), 133 (42 %), 71 (100 %); HRMS (EI/Double Focusing) m/z: M+ Calcd. for
C29H23NO3S2 497.1119; found 497.1115.
5'-(4-(Bis(4-(dodecylthio)phenyl)amino)phenyl)-[2,2'-bithiophene]-5-carbaldehyde (3e) was
prepared from 4ꢀ(dodecylthio)ꢀNꢀ(4ꢀ(dodecylthio)phenyl)ꢀNꢀ(4ꢀ(thiophenꢀ2ꢀyl)phenyl)aniline (1e)
(727 mg, 1.00 mmol), 2a (168 mg, 1.50 mmol), Pd(OAc)2 (12 mg, 0.05 mmol), Cu(OAc)2 (273
mg, 1.50 mmol), pyridine (119 mg, 1.50 mmol), and oꢀxylene (2 mL) according to the general
procedure C and yielding after column chromatography (dichloromethane : hexanes = 60 : 40) the
o
1
pure product 3e (544 mg, 65 %). Orange solid; m.p.: 83.8ꢀ85.0 C. H NMR (CDCl3, 300 MHz,
ppm): δ 9.87 (s, 1 H), 7.69 (d, J = 4.2 Hz, 1 H), 7.48 (d, J = 8.7 Hz, 2 H), 7.33 (d, J = 3.9 Hz, 1 H),
7.10ꢀ7.30 (comp, 6 H), 6.79ꢀ7.10 (comp, 6 H), 2.91 (t, J = 7.4 Hz, 4 H), 1.56ꢀ1.75 (comp, 4 H),
1.10ꢀ1.49 (comp, 36 H), 0.90 (t, J = 6.5 Hz, 6 H); 13C NMR (CDCl3, 75 MHz, ppm): δ 182.4,
147.5, 147.4, 146.1, 145.1, 141.3, 137.5, 134.2, 131.2, 130.7, 127.4, 127.3, 126.7, 125.0, 123.8,
123.3, 34.4, 32.0, 29.7, 29.68, 29.64, 29.57, 29.4, 29.3, 29.2, 28.9, 22.7, 14.2; MS (FAB): 838
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The Journal of Organic Chemistry
([M+H]+, 26 %), 538 (7 %), 73 (100 %); HRMS (FAB/Double Focusing) m/z: M+ Calcd. for
C51H67NOS4 837.4105; found 837.4096.
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2
3
4
5
6
7
8
9
Dimethyl 5-(4-(diphenylamino)phenyl)-5'-formyl-[2,2'-bithiophene]-3,4-dicarboxylate (3f)
was prepared from dimethyl 2ꢀ(4ꢀ(diphenylamino)phenyl)thiopheneꢀ3,4ꢀdicarboxylate23a (1f)
(443 mg, 1.00 mmol), 2a (168 mg, 1.50 mmol), Pd(OAc)2 (12 mg, 0.05 mmol), Cu(OAc)2 (273
mg, 1.50 mmol), pyridine (119 mg, 1.50 mmol), and oꢀxylene (2 mL) according to the general
procedure C and yielding after column chromatography (using the eluent with a gradient polarity:
from dichloromethane : hexanes = 20 : 80 to dichloromethane : hexanes = 40 : 60) the pure
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60
o
1
product 3f (288 mg, 52 %). Orange solid; m.p.: 164.5ꢀ165.4 C. H NMR (CDCl3, 300 MHz,
ppm): δ 9.91 (s, 1 H), 7.72 (d, J = 3.9 Hz, 1 H), 7.42 (d, J = 3.9 Hz, 1 H), 7.26ꢀ7.39 (comp, 6 H),
7.00ꢀ7.22 (comp, 8 H), 3.90 (s, 3 H), 3.82 (s, 3 H); 13C NMR (CDCl3, 75 MHz, ppm): δ 182.7,
164.2 (two peaks), 149.1, 148.2, 147.0, 144.3, 142.5, 136.3, 135.1, 131.3, 129.8, 129.5, 129.0,
128.8, 125.4 (two peaks), 124.0, 121.5, 52.8, 52.5; MS (EI, 70 eV): 553 (M+, 1 %), 472 (100 %),
457 (75 %), 189 (47 %), 57 (54 %); HRMS (EI/Double Focusing) m/z: M+ Calcd. for
C31H23NO5S2 553.1018; found 553.1014.
5-(4-(Diphenylamino)phenyl)-[2,2'-bithiophene]-3,4,5'-tricarbaldehyde (3g) was prepared
from 2ꢀ(4ꢀ(diphenylamino)phenyl)thiopheneꢀ3,4ꢀdicarbaldehyde (1g) (383 mg, 1.00 mmol), 2a
(168 mg, 1.50 mmol), Pd(OAc)2 (12 mg, 0.05 mmol), Ag2CO3 (413 mg, 1.50 mmol), pyridine
o
(119 mg, 1.50 mmol), and oꢀxylene (2 mL) according to the general procedure C (100 C, 12 h
for this example) and yielding after column chromatography (ethyl acetate : dichloromethane :
1
hexanes = 1 : 80 : 19) the pure product 3g (296 mg, 60 %). Red liquid. H NMR (CDCl3, 300
MHz, ppm): δ 10.39 (s, 1 H), 10.04 (s, 1H), 9.92 (s, 1 H), 7.75 (d, J = 3.9 Hz, 1 H), 7.67 (d, J =
3.9 Hz, 1 H), 7.20ꢀ7.40 (comp, 6 H), 6.85ꢀ7.20 (comp, 8 H); 13C NMR (CDCl3, 75 MHz, ppm): δ
187.4, 186.7, 182.9, 157.2, 150.2, 146.6, 145.2, 141.3, 139.6, 136.15, 136.10, 135.6, 131.0 (two
peaks), 129.7, 125.7, 124.5, 121.8, 121.2; MS (EI, 70 eV): 493 (M+, 5 %), 191 (14 %), 84 (100
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%); HRMS (EI/Double Focusing) m/z: M+ Calcd. for C29H19NO3S2 493.0806; found 493.0813.
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5-(3-(4-(Diphenylamino)phenyl)-5-(2-ethylhexyl)-4,6-dioxo-5,6-dihydro-4H-thieno[3,4-c]pyr
7
8
9
rol-1-yl)thiophene-2-carbaldehyde15
(3h)
was
prepared
from
1ꢀ(4ꢀ(diphenylamino)phenyl)ꢀ5ꢀ(2ꢀethylhexyl)ꢀ4Hꢀthieno[3,4ꢀc]pyrroleꢀ4,6(5H)ꢀdione15 (1h) (508
mg, 1.00 mmol), 2a (336 mg, 3.00 mmol), Pd(OAc)2 (12 mg, 0.05 mmol), Ag2CO3 (413 mg, 1.50
mmol), pyridine (119 mg, 1.50 mmol), and oꢀxylene (2 mL) according to the general procedure C
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60
o
(100 C, 12 h for this example) and yielding after column chromatography (using the eluent with
a gradient polarity: from dichloromethane : hexanes = 40 : 60 to dichloromethane : hexanes = 60 :
o
1
40) the pure product 3h (363 mg, 56 %). Red solid; m.p.: 153.4ꢀ154.5 C. H NMR (CDCl3, 300
MHz, ppm): δ 9.89 (s, 1 H), 8.17 (d, J = 4.2 Hz, 1 H), 7.96 (d, J = 8.9 Hz, 2 H), 7.71 (d, J = 4.2
Hz, 1 H), 7.27ꢀ7.47 (comp, 4 H), 7.08ꢀ7.25 (comp, 6 H), 7.03 (d, J = 8.9 Hz, 2 H), 3.54 (d, J = 7.2
Hz, 2 H), 1.74ꢀ1.98 (m, 1 H), 1.26ꢀ1.47 (comp, 8 H), 0.81ꢀ1.04 (comp, 6 H); 13C NMR (CDCl3,
75 MHz, ppm): δ 182.5, 163.0, 162.7, 150.1, 146.8, 146.5, 144.1, 141.4, 136.7, 133.3, 132.2,
129.9, 129.6, 129.3, 128.1, 125.8, 124.5, 122.6, 120.7, 42.6, 38.3, 30.6, 28.6, 23.9, 23.0, 14.1,
10.5.
5-(5-(4-(Diphenylamino)phenyl)-1-methyl-1H-pyrrol-2-yl)thiophene-2-carbaldehyde25 (3i)
was prepared from 4ꢀ(1ꢀmethylꢀ1Hꢀpyrrolꢀ2ꢀyl)ꢀN,Nꢀdiphenylaniline23a (1i) (324 mg, 1.00 mmol),
2a (336 mg, 3.00 mmol), Pd(OAc)2 (12 mg, 0.05 mmol), Ag2CO3 (413 mg, 1.50 mmol), pyridine
o
(119 mg, 1.50 mmol), and oꢀxylene (2 mL) according to the general procedure C (100 C, 12 h
for this example) and yielding after column chromatography (using the eluent with a gradient
polarity: from dichloromethane : hexanes = 40 : 60 to dichloromethane : hexanes = 80 : 20) the
1
pure product 3i (221 mg, 51 %). Dark liquid. H NMR (CDCl3, 300 MHz, ppm): δ 9.85 (s, 1 H),
7.72 (d, J = 3.9 Hz, 1 H), 7.26ꢀ7.42 (comp, 6 H), 7.01ꢀ7.21 (comp, 9 H), 6.63 (d, J = 3.9 Hz, 1 H),
6.28 (d, J = 3.9 Hz, 1 H), 3.79 (s, 3 H); 13C NMR (CDCl3, 75 MHz, ppm): δ 182.5, 147.4, 145.8,
140.7, 139.7, 137.5, 129.7, 129.4, 128.2, 125.9, 124.8, 124.1, 123.4, 122.9, 112.2, 109.5, 34.6.
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5'-(3,6-Di-tert-butyl-9H-carbazol-9-yl)-[2,2'-bithiophene]-5-carbaldehyde (3j) was prepared
from 3,6ꢀdiꢀtertꢀbutylꢀ9ꢀ(thiophenꢀ2ꢀyl)ꢀ9Hꢀcarbazole26 (1j) (362 mg, 1.00 mmol), 2a (336 mg,
3.00 mmol), Pd(OAc)2 (12 mg, 0.05 mmol), Ag2CO3 (413 mg, 1.50 mmol), pyridine (119 mg,
o
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1.50 mmol), and oꢀxylene (2 mL) according to the general procedure C (100 C, 12 h for this
example) and yielding after column chromatography (dichloromethane : hexanes = 60 : 40) the
o
1
pure product 3j (351 mg, 70 %). Golden yellow solid; m.p.: 194.0ꢀ194.9 C. H NMR (CDCl3,
300 MHz, ppm): δ 9.88 (s, 1 H), 8.11ꢀ8.20 (comp, 2 H), 7.67 (d, J = 3.9 Hz, 1 H), 7.46ꢀ7.60
(comp, 4 H), 7.41 (d, J = 3.9 Hz, 1 H), 7.25 (d, J = 3.9 Hz, 1 H), 7.15 (d, J = 3.9 Hz, 1 H), 1.50 (s,
18 H); 13C NMR (CDCl3, 75 MHz, ppm): δ 182.5, 146.8, 144.2, 141.9, 140.9, 139.8, 137.4, 133.2,
125.1, 124.7, 124.2 (two peaks), 123.9, 116.4, 109.7, 34.8, 32.0; MS (EI, 70 eV): 472 ([M+H]+, 3
%), 280 (36 %), 234 (66 %), 167 (42 %), 149 (100 %); HRMS (EI/Double Focusing) m/z:
[M+H]+ Calcd. for C29H29NOS2 471.1691; found 471.1678.
5'-(4-(3,6-Di-tert-butyl-9H-carbazol-9-yl)phenyl)-[2,2'-bithiophene]-5-carbaldehyde27
(3k)
was prepared from 3,6ꢀdiꢀtertꢀbutylꢀ9ꢀ(4ꢀ(thiophenꢀ2ꢀyl)phenyl)ꢀ9Hꢀcarbazole23a (1k) (437 mg,
1.00 mmol), 2a (168 mg, 1.50 mmol), Pd(OAc)2 (12 mg, 0.05 mmol), Cu(OAc)2 (273 mg, 1.50
mmol), pyridine (119 mg, 1.50 mmol), and oꢀxylene (2 mL) according to the general procedure C
and yielding after column chromatography (dichloromethane : hexanes = 60 : 40) the pure
o
1
product 3k (350 mg, 64 %). Golden yellow solid; m.p.: 235.0ꢀ235.6 C. H NMR (CDCl3, 300
MHz, ppm): δ 9.88 (s, 1 H), 8.25 (d, J = 1.5 Hz, 2 H), 7.81 (d, J = 8.4 Hz, 2 H), 7.60ꢀ7.69 (comp,
3 H), 7.51ꢀ7.57 (comp, 2 H), 7.46 (d, J = 8.4 Hz, 2 H), 7.34 (dd, J = 10.5, 3.9 Hz, 2 H), 7.27 (d, J
= 3.9 Hz, 1 H), 1.56 (s, 18 H); 13C NMR (CDCl3, 75 MHz, ppm): δ 182.5, 146.9, 145.2, 143.3,
141.7, 139.0, 138.1, 137.5, 135.4, 131.9, 127.3, 127.1, 127.0, 124.6, 124.2, 123.8, 123.7, 116.4,
109.3, 34.8, 32.1.
5-(7-(4-(3,6-Di-tert-butyl-9H-carbazol-9-yl)phenyl)-2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)
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thiophene-2-carbaldehyde
(3l)
was
prepared
from
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3,6ꢀdiꢀtertꢀbutylꢀ9ꢀ(4ꢀ(2,3ꢀdihydrothieno[3,4ꢀb][1,4]dioxinꢀ5ꢀyl)phenyl)ꢀ9Hꢀcarbazole23a
(1l)
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(496 mg, 1.00 mmol), 2a (168 mg, 1.50 mmol), Pd(OAc)2 (12 mg, 0.05 mmol), Cu(OAc)2 (273
mg, 1.50 mmol), pyridine (119 mg, 1.50 mmol), and oꢀxylene (2 mL) according to the general
procedure C and yielding after column chromatography (using the eluent with a gradient polarity:
from dichloromethane : hexanes = 40 : 60 to dichloromethane : hexanes = 80 : 20) the pure
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product 3l (333mg, 55 %). Golden yellow solid; m.p.: 232.9ꢀ233.5 C. H NMR (CDCl3, 300
MHz, ppm): δ 9.87 (s, 1 H), 8.19 (d, J = 1.5 Hz, 2 H), 7.96 (d, J = 8.7 Hz, 2 H), 7.55ꢀ7.70 (comp,
3 H), 7.38ꢀ7.54 (comp, 4 H), 7.30 (d, J = 4.2 Hz, 1 H), 4.33ꢀ4.50 (comp, 4 H), 1.51 (s, 18 H); 13C
NMR (CDCl3, 75 MHz, ppm): δ 182.6, 144.6, 143.1, 140.9, 140.7, 139.0, 138.6, 137.1, 137.0,
130.7, 127.5, 126.8, 123.7, 123.5, 123.1, 117.4, 116.4, 109.5, 109.3, 65.1, 64.8, 34.8, 32.1; MS
(EI, 70 eV): 606 ([M+H]+, 2 %), 554 (100 %), 526 (6 %); HRMS (EI/Double Focusing) m/z: M+
Calcd. for C37H35NO3S2 605.2058; found 605.2053.
5'-(9-(2-Ethylhexyl)-9H-carbazol-3-yl)-[2,2'-bithiophene]-5-carbaldehyde (3m) was prepared
from 9ꢀ(2ꢀethylhexyl)ꢀ3ꢀ(thiophenꢀ2ꢀyl)ꢀ9Hꢀcarbazole23a (1m) (362 mg, 1.00 mmol), 2a (168 mg,
1.50 mmol), Pd(OAc)2 (12 mg, 0.05 mmol), Cu(OAc)2 (273 mg, 1.50 mmol), pyridine (119 mg,
1.50 mmol), and oꢀxylene (2 mL) according to the general procedure C and yielding after column
chromatography (using the eluent with a gradient polarity: from dichloromethane : hexanes = 20 :
80 to dichloromethane : hexanes = 40 : 60) the pure product 3m (250 mg, 53 %). Orange solid;
m.p.: 110.5ꢀ110.9 oC. 1H NMR (CDCl3, 300 MHz, ppm): δ 9.83 (s, 1 H), 8.27 (d, J = 1.8 Hz, 1 H),
8.13 (d, J = 7.5 Hz, 1 H), 7.67 (dd, J = 8.7, 1.8 Hz, 1 H), 7.61 (d, J = 3.9 Hz, 1 H), 7.44ꢀ7.55 (m,
1 H), 7.23ꢀ7.44 (comp, 5 H), 7.20 (d, J = 3.9 Hz, 1 H), 4.11 (d, J = 6.0 Hz, 2 H), 1.97ꢀ2.16 (m, 1
H), 1.19ꢀ1.51 (comp, 8 H), 0.79ꢀ1.00 (comp, 6 H); 13C NMR (CDCl3, 75 MHz, ppm): δ 182.4,
147.9, 147.7, 141.4, 140.94, 140.85, 137.6, 133.6, 127.3, 126.2, 124.5, 123.8, 123.5, 123.3, 122.9,
122.7, 120.5, 119.3, 117.6, 109.41, 109.37, 47.4, 39.4, 31.0, 28.9, 24.5, 23.1, 14.1, 11.0; MS (EI,
70 eV): 472 ([M+H]+, 2 %), 84 (100 %); HRMS (EI/Double Focusing) m/z: M+ Calcd. for
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C29H29NOS2 471.1691; found 471.1685.
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5-(5-(2-Ethylhexyl)-3-(9-hexyl-9H-carbazol-3-yl)-4,6-dioxo-5,6-dihydro-4H-thieno[3,4-c]pyr
rol-1-yl)thiophene-2-carbaldehyde (3n) was prepared from
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5ꢀ(2ꢀethylhexyl)ꢀ1ꢀ(9ꢀhexylꢀ9Hꢀcarbazolꢀ3ꢀyl)ꢀ4Hꢀthieno[3,4ꢀc]pyrroleꢀ4,6(5H)ꢀdione (1n) (514
mg, 1.00 mmol), 2a (336 mg, 3.00 mmol), Pd(OAc)2 (12 mg, 0.05 mmol), Ag2CO3 (413 mg, 1.50
mmol), pyridine (119 mg, 1.50 mmol), and oꢀxylene (2 mL) according to the general procedure C
o
(100 C, 12 h for this example) and yielding after column chromatography (dichloromethane :
o
1
hexanes = 60 : 40) the pure product 3n (393 mg, 63 %). Red solid; m.p.: 195.8ꢀ197.3 C. H
NMR (CDCl3, 300 MHz, ppm): δ 9.79 (s, 1 H), 8.74 (s, 1 H), 8.06ꢀ8.28 (comp, 2 H), 8.00 (d, J =
3.3 Hz, 1 H), 7.53 (d, J = 3.3 Hz, 1 H), 7.41ꢀ7.50 (m, 1 H), 7.17ꢀ7.38 (comp, 3 H), 4.18 (t, J = 6.9
Hz, 2 H), 3.49 (d, J = 7.2 Hz, 2 H), 1.72 (app s, 3 H), 1.34 (app s, 14 H), 0.64ꢀ1.13 (comp, 9 H);
13C NMR (CDCl3, 75 MHz, ppm): δ 182.5, 162.9, 162.6, 148.2, 143.7, 141.39, 141.35, 140.9,
136.5, 132.8, 132.1, 129.6, 127.7, 126.4, 125.9, 123.1, 122.7, 121.0, 120.9, 120.5, 119.8, 109.1,
108.8, 43.2, 42.5, 38.3, 31.5, 30.6, 28.9, 28.6, 26.9, 23.9, 23.1, 22.6, 14.2, 14.1, 10.5; MS (FAB):
626 ([M+2]+, 100 %), 553 (29 %), 495 (19 %); HRMS (FAB/Double Focusing) m/z: M+ Calcd.
for C37H40N2O3S2 624.2480; found 624.2479.
5'-(9-(4-(Methylthio)phenyl)-9H-carbazol-3-yl)-[2,2'-bithiophene]-5-carbaldehyde (3o) was
prepared from 9ꢀ(4ꢀ(methylthio)phenyl)ꢀ3ꢀ(thiophenꢀ2ꢀyl)ꢀ9Hꢀcarbazole (1o) (371 mg, 1.00
mmol), 2a (336 mg, 3.00 mmol), Pd(OAc)2 (12 mg, 0.05 mmol), Ag2CO3 (413 mg, 1.50 mmol),
pyridine (119 mg, 1.50 mmol), and oꢀxylene (2 mL) according to the general procedure C (100 oC,
12 h for this example) and yielding after column chromatography (dichloromethane : hexanes =
o
1
50 : 50) the pure product 3o (269 mg, 56 %). Orange solid; m.p.: 180.9ꢀ182.3 C. H NMR
(CDCl3, 300 MHz, ppm): δ 9.84 (s, 1 H), 8.32 (d, J = 1.2 Hz, 1 H), 8.18 (d, J = 7.8 Hz, 1 H),
7.59ꢀ7.68 (comp, 2 H), 7.02ꢀ7.52 (comp, 11 H), 2.60 (s, 3 H); 13C NMR (CDCl3, 75 MHz, ppm):
δ 182.4, 147.55, 147.52, 141.4, 141.1, 140.8, 138.4, 137.5, 134.1, 133.9, 127.7, 127.4, 127.3,
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126.6, 125.7, 124.2, 123.9, 123.6, 123.2, 123.1, 120.5, 120.4, 117.7, 110.2, 110.0, 15.9; MS (EI,
70 eV): 481 (M+, 1 %), 334 (8 %), 135 (42 %), 57 (100 %); HRMS (EI/Double Focusing) m/z:
M+ Calcd. for C28H19NOS3 481.0629; found 481.0629.
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5'-(9-(4-Fluorophenyl)-9H-carbazol-3-yl)-[2,2'-bithiophene]-5-carbaldehyde
(3p)
was
prepared from 9ꢀ(4ꢀfluorophenyl)ꢀ3ꢀ(thiophenꢀ2ꢀyl)ꢀ9Hꢀcarbazole (1p) (343 mg, 1.00 mmol), 2a
(168 mg, 1.50 mmol), Pd(OAc)2 (12 mg, 0.05 mmol), Cu(OAc)2 (273 mg, 1.50 mmol), pyridine
(119 mg, 1.50 mmol), and oꢀxylene (2 mL) according to the general procedure C and yielding
after column chromatography (dichloromethane : hexanes = 50 : 50) the pure product 3p (390 mg,
o
1
86 %). Yellow solid; m.p.: 177.0ꢀ178.0 C. H NMR (CDCl3, 300 MHz, ppm): δ 9.83 (s, 1 H),
8.33 (d, J = 1.5 Hz, 1 H), 8.07ꢀ8.29 (m, 1 H), 7.26ꢀ7.83 (comp, 12 H), 7.23 (d, J = 3.9 Hz, 1 H);
13C NMR (CDCl3, 75 MHz, ppm): δ 182.5, 147.5, 147.4, 141.6, 141.1, 140.9, 137.6, 134.0, 133.2
4
3
(d, JCꢀF = 3.0 Hz), 128.9 (d, JCꢀF = 8.5 Hz), 127.3, 126.7, 125.8, 124.3, 123.9, 123.7, 123.3,
2
123.1, 120.6, 120.5, 117.0 (d, JCꢀF = 22.7 Hz), 110.0, 109.9; MS (EI, 70 eV): 453 (M+, 9 %), 411
(18 %), 167 (41 %), 149 (58 %), 84 (100 %); HRMS (EI/Double Focusing) m/z: M+ Calcd. for
C27H16FNOS2 453.0657; found 453.0650.
4-(3-(5'-Formyl-[2,2'-bithiophen]-5-yl)-9H-carbazol-9-yl)benzonitrile (3q) was prepared from
4ꢀ(3ꢀ(thiophenꢀ2ꢀyl)ꢀ9Hꢀcarbazolꢀ9ꢀyl)benzonitrile (1q) (350 mg, 1.00 mmol), 2a (168 mg, 1.50
mmol), Pd(OAc)2 (12 mg, 0.05 mmol), Cu(OAc)2 (273 mg, 1.50 mmol), pyridine (119 mg, 1.50
mmol), and oꢀxylene (2 mL) according to the general procedure C and yielding after column
chromatography (dichloromethane : hexanes = 80 : 20) the pure product 3q (345 mg, 75 %).
o
1
Golden yellow solid; m.p.: 219.2ꢀ220.1 C. H NMR (CDCl3, 300 MHz, ppm): δ 9.88 (s, 1 H),
8.35 (d, J = 1.5 Hz, 1 H), 8.20 (d, J = 7.5 Hz, 1 H), 7.95 (d, J = 8.4 Hz, 2 H), 7.75 (d, J = 8.4 Hz,
2 H), 7.65ꢀ7.73 (comp, 2 H), 7.29ꢀ7.54 (comp, 7 H); 13C NMR (CDCl3, 75 MHz, ppm): δ 182.5,
147.4, 146.9, 141.6, 141.3, 140.5, 139.7, 137.5, 134.4, 134.1, 127.3, 127.1, 127.0, 126.8, 124.63,
124.58, 123.8, 123.7, 123.6, 121.5, 120.8, 117.9, 110.9, 110.1, 109.8; MS (EI, 70 eV): 460 (M+, 7
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%), 441 (23 %), 84 (100 %); HRMS (EI/Double Focusing) m/z: M+ Calcd. for C28H16N2OS2
460.0704; found 460.0711.
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5'-(9-(4-Benzoylphenyl)-9H-carbazol-3-yl)-[2,2'-bithiophene]-5-carbaldehyde
(3r)
was
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prepared from phenyl(4ꢀ(3ꢀ(thiophenꢀ2ꢀyl)ꢀ9Hꢀcarbazolꢀ9ꢀyl)phenyl)methanone (1r) (429 mg,
1.00 mmol), 2a (168 mg, 1.50 mmol), Pd(OAc)2 (12 mg, 0.05 mmol), Cu(OAc)2 (273 mg, 1.50
mmol), pyridine (119 mg, 1.50 mmol), and oꢀxylene (2 mL) according to the general procedure C
and yielding after column chromatography (dichloromethane : hexanes = 80 : 20) the pure
product 3r (383 mg, 71 %). Red solid; m.p.: 189.5ꢀ190.0 oC. 1H NMR (CDCl3, 300 MHz, ppm): δ
9.83 (s, 1 H), 8.30 (d, J = 1.5 Hz, 1 H), 8.18 (d, J = 7.5 Hz, 1 H), 8.08 (d, J = 8.4 Hz, 2 H), 7.93 (d,
J = 7.2 Hz, 2 H), 7.42ꢀ7.77 (comp, 10 H), 7.37 (app t, 1 H), 7.32 (d, J = 3.9 Hz, 1 H), 7.27 (d, J =
3.9 Hz, 1 H), 7.23 (d, J = 3.9 Hz, 1 H); 13C NMR (CDCl3, 75 MHz, ppm): δ 195.5, 182.4, 147.4,
147.1, 141.2, 141.1, 140.8, 140.0, 137.6, 137.3, 136.2, 134.1, 132.8, 132.0, 130.1, 128.5, 127.3,
126.8, 126.3, 126.1, 124.4, 123.7, 123.6, 123.4, 121.1, 120.7, 117.7, 110.3, 110.1; MS (FAB): 539
(M+, 3 %), 501 (5 %), 307 (50 %), 89 (100 %); HRMS (FAB/Double Focusing) m/z: M+ Calcd.
for C34H21NO2S2 539.1014; found 539.1020.
5'-(10-Hexyl-10H-phenothiazin-3-yl)-[2,2'-bithiophene]-5-carbaldehyde (3s) was prepared
from 10ꢀhexylꢀ3ꢀ(thiophenꢀ2ꢀyl)ꢀ10Hꢀphenothiazine28 (1s) (365 mg, 1.00 mmol), 2a (168 mg,
1.50 mmol), Pd(OAc)2 (12 mg, 0.05 mmol), Cu(OAc)2 (273 mg, 1.50 mmol), pyridine (119 mg,
1.50 mmol), and oꢀxylene (2 mL) according to the general procedure C and yielding after column
chromatography (using the eluent with a gradient polarity: from dichloromethane : hexanes = 40 :
60 to dichloromethane : hexanes = 60 : 40) the pure product 3s (271 mg, 57 %). Red viscous
1
liquid. H NMR (CDCl3, 300 MHz, ppm): δ 9.85 (s, 1 H), 7.65 (d, J = 3.9 Hz, 1 H), 7.32ꢀ7.44
(comp, 2 H), 7.29 (d, J = 3.6 Hz, 1 H), 7.02ꢀ7.14 (comp, 3 H), 7.13 (d, J = 3.9 Hz, 1 H), 6.77ꢀ7.02
(comp, 3 H), 3.85 (t, J = 7.2 Hz, 2 H), 1.70ꢀ2.02 (comp, 2 H), 1.26ꢀ1.53 (comp, 6 H), 0.90 (t, J =
6.9 Hz, 3 H); 13C NMR (CDCl3, 75 MHz, ppm): δ 182.5, 147.3, 145.4, 145.2, 144.6, 141.2, 137.6,
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