HELVETICA
chimica acta
Accepted Article
Title: Twofold Alkenylation of Thiophenes with N-Vinylcarbazole via
Iron-Catalyzed Regioselective C–H/C–H Coupling
Authors: Rui Shang, Takahiro Doba, and Eiichi Nakamura
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To be cited as: Helv. Chim. Acta 2023, e202300210
Link to VoR: https://doi.org/10.1002/hlca.202300210
www.helv.wiley.com
Twofold Alkenylation of Thiophenes with N-Vinylcarbazole via IronCatalyzed Regioselective C–H/C–H Coupling
Takahiro Doba,a Rui Shang,*a and Eiichi Nakamura*a
a
Department of Chemistry, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan,
e-mail: rui@chem.s.u-tokyo.ac.jp, nakamura@chem.s.u-tokyo.ac.jp
Dedicated to Prof. Alois Fürstner, President of the 56th Bürgenstock-Conference 2023
The incorporation of the vinylene motif into conjugated molecules notably elevates the HOMO level, augmenting both emissive and conductive
properties while enhancing responsiveness to external stimuli. This study focuses on the regioselective C–H/C–H coupling of N-vinylcarbazole
with thiophenes, offering an efficient route to N-vinylene-incorporated conjugated molecules for the development of organic electronic materials.
Traditional palladium-catalyzed Fujiwara-Moritani (FM) reactions proved ineffective for C–H alkenylation with N-vinylcarbazole. In response, we
have developed an iron-catalyzed twofold alkenylation method for conjugated thiophenes with N-vinylcarbazole, utilizing trimethylaluminum as
the base and diethyl oxalate as the oxidant. This reaction occurs regioselectively at the C2–H (or C5–H) bond of the thiophenes and the terminal
position of N-vinylcarbazole. It also successfully produces short thiophene polymers end-capped with N-vinylcarbazole, demonstrating the
potential for synthesizing polymeric donor materials. The enamine products exhibit blue-to-green emission, high fluorescence quantum yield,
and visible light responsivity for stereo-isomerization, indicating promising applications in organic electronics.
Keywords: Iron catalysis, C–H activation, Alkenylation, Thiophene, N-vinylcarbazole, Organic electronic materials, End-capping.
Introduction
Vinylene-incorporated compounds have been widely applied in
a
materials science due to their narrow HOMO-LUMO gap,[1, 2] emissive
properties,
3
and high responsivity toward external stimuli.[
S
π
S
4 ]
C-H/C-H
coupling
+
N
Considering these unique characteristics, integrating a vinylene unit
between thiophene and carbazole opens new avenues in developing
n = 1 or more
b
materials have seen extensive use in organic light-emitting diodes and
photovoltaics.
N
n
N
conjugated materials based on carbazole and thiophene. These
[ 5 ]
S
π
S
While oxidative C–H alkenylation using N-
S
cat. Fe(III)
cat. trisphosphine
H
S
H +
N
N
AlMe3
DEO
vinylcarbazole offers a streamlined approach, Fujiwara-Moritani (FM)
(Ar–H)
type reactions[6,7] face challenges with N-vinylcarbazole primarily due
AlMe3
to inverted polarity that complicates the carbometallation step.[ 8 ]
Me
Given the widespread presence of dithiophenes and bisthiophenes in
[FeIII]
Me
I
organic optoelectronic materials, we are particularly interested in
O
EtO
O
EtO
O
AlMe
– Me–H
O
EtO
OEt
V
[FeI]
+ DEO
AlMe3
VI
twofold alkenylation of them with N-vinylcarbazole.[9] We also aim to
further apply this method for synthesizing polythiophenes endN
capped with two N-vinylcarbazoles (Figure 1a). The iron-catalyzed C–
H/C–H coupling approach we recently developed by using an Fe(III)
H
H
S
S
[FeIII]
salt, a trisphosphine ligand, AlMe3 as base, and diethyl oxalate (DEO)
N
N
Me
II
as oxidant has proven uniquely effective for this synthetic purpose.
[FeIII]
S
[FeIII]
Me
– Me–H
III
IV
Figure 1. Regioselective C–H alkenylation of bis(di)thiophenes with N-
Figure 1b illustrates the reaction design for the iron-catalyzed
vinylcarbazole. (a) Twofold alkenylation of (oligo)thiophenes with N-
alkenylation of a thiophene with N-vinylcarbazole.
vinylcarbazole through regioselective C–H/C–H coupling. (b) A proposed
1
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mechanism for iron-catalyzed C–H/C–H coupling using DEO and AlMe3. DEO:
HOMO level further increases by 0.22 eV while the LUMO level remains
diethyl oxalate.
unchanged, resulting in a HOMO-LUMO gap of 3.50 eV. Compound D,
a Z-isomer of C, had a LUMO level close to that of C, whereas the
The reaction first forms a thienyl iron intermediate II from a Me–Fe(III)
HOMO level dropped by 0.21 eV, resulting in the increase of the
intermediate I by deprotonative metallation of thienyl C–H bond,[10]
HOMO-LUMO gap by 0.19 eV. The calculation results indicate that the
where the regioselectivity was largely determined by the acidity of C–
E- coupling products of N-vinylcarbazole with thiophenes of interest
H bonds.[11] N-vinylcarbazole nucleophilically attacks intermediate II to
in materials science are promising electron-donor materials because
give an iminium intermediate III, which then forms a heteroleptic Fe(III)
of high HOMO energies and narrow HOMO-LUMO gap.
intermediate IV via deprotonation of acidic alpha-C–H bond by methyl
In recognizing the potential of coupling N-vinylcarbazole units
anion. Reductive elimination of IV gives the coupling product and an
with thiophenes, we conducted a thorough investigation of various
Fe(I) species (V), which is oxidized back to Fe(III) by DEO in
reaction parameters. Figure 3 shows how each parameter influences
combination with Lewis acidic Al(III).[ 12] The low redox potential of
the yields and selectivity of alkenylation and thiophene-dimerization
Fe(III)/Fe(I) (< 0.55 V vs NHE)[13] allows the catalyst turnover by using a
products.[12] As N-vinylcarbazole presents a nucleophilic enamine
combination of DEO and Al(III) as an oxidant. The strong oxophilicity
which may attack ArFe(III) intermediate generated after C–H activation
of Al(III) to form thermodynamically stable five-membered ring
(II, in Figure 1b), N-vinylcarbazole was added to the iron-catalyzed C–
aluminum enediolate (VI) also contributes as a driving force for the
H/C–H thienyl homocoupling. The desired alkenylation product (3)
catalyst turnover. Applying this reaction to thiophenes that possess
was obtained in 72% yield using 1.0 equiv of 2-phenylthiophene (1)
two reactive C–H bonds, dialkenylated thiophenes and polythiophenes
and 1.5 equiv of N-vinylcarbazole (2) as substrates, 10 mol % of
were obtained in one step. The obtained new alkenylation products
Fe(acac)3 as a catalyst, 11 mol % of TP as a ligand,[14] 3.0 equiv of AlMe3
showed blue to green emission, high fluorescence quantum yield, light
as a base,[15] and 2.0 equiv of diethyl oxalate (DEO) as an oxidant.
responsivity, and high hydro-stability.
Under this condition, the cross-coupling product (3) was obtained with
high E/Z selectivity, accompanied by the formation of the
Results and Discussion
homocoupling product (4) in 20% yield (entry 1). As expected,
reducing the amount of 2 resulted in generation of increased amount
To understand the change of electronic properties by vinylene
of homocoupling (entry 2). However, further increase of 2 did not
incorporation, HOMO-LUMO energies of four model compounds (A,
improve the selectivity of cross-coupling/homocoupling (entry 3).
B, C, and D) were calculated at the level of B3LYP/6-31G(d,p) (Figure
Reaction using a limiting amount of 2 and a slight excess of 1 also
2). When a carbazole group was directly connected to the 2-position
affords 2 in high yield (entry 4), suggesting application of the reaction
of phenylthiophene, the HOMO-LUMO gap was calculated to be 4.18
for the efficient twofold thienylation of divinylcarbazoles (vide infra).
eV (A). When an N-phenylene group, a frequently encountered
Investigation of the temperature effect showed that the temperature
structure in carbazole-based optoelectronic materials, was installed (B),
affected
the LUMO level dropped by 0.26 eV and the HOMO level rose by 0.20
not
only
reaction
efficiency
but
also
cross-
coupling/homocoupling selectivity (entries 1, 5–6). 3 was obtained in
eV due to the conjugation extension, resulting in the decrease of
84% yield with only 14% yield of 4 at an optimal temperature of 50 °C.
HOMO-LUMO gap to 3.72 eV. For compound C with an N-vinyl group
The reaction at 40 °C resulted in large recovery of 1 (entry 7).
inserted, the HOMO is largely distributed on the vinylene moiety. The
2
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–1.27 eV
LUMO
–1.53 eV
–1.53 eV
3.50 eV
3.72 eV
4.18 eV
–1.55 eV
3.69 eV
–5.03 eV
–5.24 eV
–5.25 eV
HOMO
–5.45 eV
S
Ph
Ph
S
Ph
A
Ph
N
N
S
N
N
S
C
B
D
Figure 2. Comparison of HOMO-LUMO energies of model compounds. Calculations were conducted at the level of B3LYP/6-31G(d,p).
Variation of all other parameters were not successful to further
S
Ph
improve the yield of 3 (entries 8–22). When the catalyst loading was
1
(1.0 equiv)
0.20 mmol
decreased to 3.0 mol %, the yield dropped and the starting materials
+
were recovered (entry 8). In contrast to the iron-catalyzed thienyl C–
N
H/C–H polycondensation, hydrate salts of iron(II) and iron(III) chlorides
H
Fe(acac)3 (10 mol %)
TP (11 mol %)
AlMe3 (3.0 equiv)
Ph
DEO (2.0 equiv)
THF (0.30 mL)
PhMe (0.30 mL)
70 °C, 15 h
S
N
Ph2P
P
+
Ph
TP
S
Ph
S
“standard condition”
were not effective for this reaction and gave slightly lower E/Z
PPh2
3
4
2
(1.5 equiv)
selectivity (entries 9, 10). AlMe3 used in 1.0 equiv resulted in a low yield,
yield (%)a
indicating that not all the methyl groups of AlMe3 can be transferred
to iron for C–H deprotonation (entry 11). Use of AlMe3 in 2.0 equiv did
not decrease the yield (entry 12), while we noticed using AlMe3 in 3.0
equiv gave a better reproducibility. Other organoaluminum reagents
tested were ineffective (entries 13–15), showing the uniqueness of
AlMe3 as a base for this reaction. Reducing the amount of DEO to 1.0
equiv slightly reduced the yield (entry 16). Other oxalates and a vicinal
dichloride used for iron-catalyzed directed C–H activation, were less
effective (entries 17–19).[ 16 ] Performing the reaction under diluted
conditions resulted in insufficient conversion (entry 20). The solvent
ratio of THF and toluene had little effect on the reaction efficiency and
selectivity (entries 21, 22).
entry
variation of conditions
1
3
E:Z
4
1
none
3
72
> 20:1
20
2
2 (1.0 equiv)
1
68
> 20:1
30
3
2 (2.0 equiv)
10
71
> 20:1
15
4
1 (1.5 equiv), 2 (1.0 equiv)
1
79
> 20:1
75b
5
60 °C
1
78
> 20:1
16
6
50 °C
0
84
> 20:1
14
7
40 °C
32
51
> 20:1
11
8
Fe(acac)3 (3.0 mol %), TP (3.3 mol %)
52
31
17:1
12
9
FeCl3•6H2O instead of Fe(acac)3
28
43
14:1
13
10
FeCl2•4H2O instead of Fe(acac)3
36
42
17:1
15
11
AlMe3 (1.0 equiv)
18
57
> 20:1
17
12
AlMe3 (2.0 equiv)
2
72
> 20:1
18
13
AMe2Cl instead of AlMe3
96
0
–
0
14
AlEt3 instead of AlMe3
96
0
–
0
15
DIBAL-H instead of AlMe3
95
0
–
0
16
DEO (1.0 equiv)
6
70
> 20:1
18
17
(COOMe)2 instead of DEO
21
55
> 20:1
18
18
(COOt-Bu)2 instead of DEO
11
29
12:1
33
19
1,2-dichloropropane instead of DEO
48
36
> 20:1
11
20
THF (0.60 mL), PhMe (0.60 mL)
10
67
> 20:1
21
21
THF (0.60 mL) instead of THF (0.30 mL)
8
70
> 20:1
21
22
PhMe (0.60 mL) instead of PhMe (0.30 mL)
4
70
> 20:1
21
Figure 3. Effect of reaction parameters.
a
Yields were determined by GC using
tridecane as an internal standard. b The yield was determined by 1H NMR using
1,3,5-trimethoxybenzene as an internal standard.
Figure 4 shows the effect of the structurally different
trisphosphine ligands on the outcome of the reaction. Trisphosphine
3
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ligands with varying substituents on the central phosphine was
Figure 4. Effect of trisphosphine ligand.
synthesized by sequential addition of two different organolithium
tridecane as an internal standard.
a
Yields were determined by GC using
reagents to triphenyl phosphite.[ 17 ] Unexpectedly, all other ligands
With the optimized reaction condition in hand (Figure 3, entry
gave lower yields of 3 compared to TP. The use of F3C-TP (entry 5)
6), several symmetrical compounds bearing unique thiophene-
resulted in accelerated generation of 4. Indolyl-TP, which is more
vinylene-carbazole linkages were synthesized. The amount of the
sterically hindered than other ligands in Figure 4, gave a low
reagents was doubled for two-fold reaction of bis(di)thiophenes. The
conversion and poor selectivity (entry 6). Benzofuryl-TP and
reaction took place at the C2–H (or C5–H) bond of thiophenes and the
benzothienyl-TP, both found effective for iron-catalyzed thienyl C–
terminal position of N-vinylcarbazoles with excellent regioselectivity.
H/C–H polycondensation, did not improve the yield (entries 7, 8).
A bisthiophene unit found in F8T2-polymer were dialkenylated in
These results indicate that the product distribution (3 v.s. 4) is mainly
excellent E/Z selectivity (5).[18] Owing to the mildness of DEO oxidant,
governed by the inherent nucleophilicity of N-vinylcarbazole toward
the reaction was applicable to electron-rich dithienylcarbazole (6), a
Fe(III) intermediate II.
useful core structure for p-type semiconductors.[19]
S
Ph
H
1
(1.0 equiv)
0.20 mmol
+
N
3
DEO (2.0 equiv)
THF (0.30 mL)
PhMe (0.30 mL)
50 °C, 15 h
N
S
Ph
Fe(acac)3 (10 mol %)
ligand (11 mol %)
AlMe3 (3.0 equiv)
+
S
Ph
S
Ph
4
2
(1.0 equiv)
yield (%)a
E:Z
4
56
15:1
22
68
> 20:1
25
73
> 20:1
24
22
54
> 20:1
21
4
66
> 20:1
30
entry
ligand
1
1
Me2N-TP
20
2
MeO-TP
5
3
TP
1
4
F-TP
5
F3C-TP
3
6
Indolyl-TP
20
42
> 20:1
33
7
Benzofuryl-TP
10
61
> 20:1
26
8
Benzothienyl-TP
3
69
> 20:1
27
Structures of trisphosphine ligands
PPh2
P
Ph2P
PPh2
X
P
Ph2P
Y
X = NMe2
(Me2N-TP)
Y = NMe
(Indolyl-TP)
OMe
(MeO-TP)
O
(Benzofuryl-TP)
H
(TP)
S
(Benzothienyl-TP)
F
(F-TP)
CF3
(F3C-TP)
4
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S
π
H
N
Fe(acac)3 (20 mol %)
TP (22 mol %)
AlMe3 (6.0 equiv)
(3.0 equiv)
DEO (4.0 equiv)
THF/PhMe
(v/v = 1/1, 0.2 M)
50 °C, 15 h
+
H
S
(1.0 equiv)
0.10–0.20 mmol
S
π
N
N
S
C10H21
C8H17 C8H17
C8H17
O
N
S
N
S
S
N
5, 44% (E:Z = > 20:1)
C8H17
N
S
O
C8H17
C8H17
C10H21
8, 40% (E:Z = > 20:1)
N
N
Ph
S
N
S
S
N
C6H13
N
6, 48% (E:Z = > 20:1)
C6H13
S
Ph
9, 62% (E:Z = 10:1)a
Ph
S
C6H13
N
N
S
N
N
S
C6H13
N
S
Ph
7, 56% (E:Z = 20:1)
10, 57% (E:Z = 4:1)a
Figure 5. Scope of iron-catalyzed twofold alkenylation of thiophenes with N-vinylcarbazoles. a With an enamine (1.0 equiv) and a thiophene (3.0 equiv), Fe(acac)3 (40
mol %), TP (44 mol %).
A bisthiophene compound containing a monomer structure of
PTAA,
[ 20 ]
Mw = 10.9 kg/mol, Mw/Mn = 1.62, and DP = 11 (DP: degree of
a common hole transporting material in optoelectronic
polymerization, Scheme 1). The Mn, Mw, and Mw/Mn were determined
devices, underwent twofold alkenylation in moderate yield (7). A fused
by analytical GPC using polystyrene standards of known length. By 1H
thiophene,
NMR, DP was determined as 10, which is in good correspondence with
4,8-dialkoxybenzo[1,2-b:4,5-b′]dithiophene,
reacted well to afford the alkenylated product (8).
[21]
was
also
In all the reactions
the DP value obtained by analytical GPC.
employing bis(di)thiophenes, oligomerization of bis(di)thiophenes
Scheme 1. Iron-catalyzed C–H/C–H coupling for synthesis of a polythiophene
accounted for their mass balance. During the investigation, we found
in-situ end-capped with N-vinylcarbazole.
that the reaction was applicable to twofold thienylation of N,N'divinyl-9H,9'H-3,3'-bicarbazole
b]carbazole (ICZ),
[22,23]
(BCZ)
and
C8H17
N,N'-divinylindolo[3,2H
using 3.0 equivalent of a thiophene coupling
C8H17
S
S
N
+
H
11, (1.0 equiv)
0.20 mmol
partner to provide conjugated N-alkenylated carbazole derivatives of
2, (0.25 equiv)
unexplored structures (9, 10).
C8H17
Because the alkenylation products were always accompanied by
N
S
C8H17
were
end-capped
by
N-vinylcarbazole
through
n
12
Mn = 6.7 kg/mol, Mw = 10.9 kg/mol
Mw/Mn = 1.62, DP = 11
41% yield (E:Z = 16:1)
C–H/C–H
heterocoupling. This supposition prompted us to apply this method
Conjugated thiophene compounds functionalized with N-
to synthesize oligothiophene or polythiophene end-capped with N-
vinylcarbazole (5, 6, 7) showed intense fluorescence in the blue region
vinylcarbazole by changing the substrate ratio.[24,25,26,27] By reacting 1.0
with high quantum yields in the range of FFL = 0.75–0.82, showing the
equiv of bisthiophene 11 as a monomer and 0.25 equiv of Nvinylcarbazole
(2)
as
an
end-capping
group
in-situ,
N
S
oligomers of bis(di)thiophenes, we wondered whether such oligomers
Fe(acac)3 (20 mol %)
TP (22 mol %)
AlMe3 (6.0 equiv)
DEO (4.0 equiv)
THF/PhMe
(v/v = 1/1, 1.20 mL)
70 °C, 24 h
potential application as emissive materials (Figure 6). A fused
both
thiophene compound (8) showed a small Stokes shift possibly because
homocoupling of 11 and cross-coupling between 11 and 2 took place
of the structural rigidity. The BCZ compound (10) had shorter
under the standard reaction conditions to afford the desired end-
absorption wavelength, which correlates with the short conjugation
capped polymer 12 in moderate chain length with Mn = 6.7 kg/mol,
5
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length of the thiophene moiety. The end-capped oligothiophene (12)
synthesis of highly conjugated compounds of interest in materials
also showed a high quantum yield of FFL = 0.41. These results
science.
demonstrate the potential of the iron-catalyzed method for the
Compound 5
Compound 6
ΦFL = 0.75
400
500
550
450
Wavelength (nm)
600
0.6
0.4
0.2
ΦFL = 0.78
0
300
650
350
400
Compound 8
600
0.4
ΦFL = 0.21
0.2
350
350
400
500
400
450
Wavelength (nm)
550
381
Abs.
FL
445
6.0
4.0
2.0
ΦFL = 0.08
0
300
600
500
550
450
Wavelength (nm)
600
650
Compound 12
Intensity (a.u.)
386
ε (104 L mol-1 cm-1)
339
0.6
0
300
ΦFL = 0.82
446
350
500
400
450
Wavelength (nm)
550
ε (104 L mol-1 cm-1)
Abs.
FL
475
Intensity (a.u.)
435 452
409
0.2
5.0
8.0
0.8
0.4
0
300
650
Abs.
FL
0.6
Compound 10
1.0
ε (105 L mol-1 cm-1)
500
550
450
Wavelength (nm)
463
0.8
Abs.
FL
3.0
2.0
1.0
ΦFL = 0.41
0
300
600
496
4.0
Intensity (a.u.)
350
Intensity (a.u.)
0.4
Abs.
FL
466
0.8
416
Intensity (a.u.)
417
0.6
0.2
1.0
ε (105 L mol-1 cm-1)
Abs.
FL
0.8
0
300
Compound 7
1.0
468
ε (105 L mol-1 cm-1)
418
Intensity (a.u.)
ε (105 L mol-1 cm-1)
1.0
350
400
500
550
450
Wavelength (nm)
600
650
Figure 6. Photophysical properties of N-vinylcarbazole cross-coupling products. Dilute solutions of products in dichloromethane were used for the measurement.
FFL was measured by absolute method using an integrating sphere.
Scheme 2 shows the photoresponsivity and the hydrostability of
twofold alkenylation of bis(di)thiophenes and polythiophenes with N-
the enamine product. Photoisomerization to give the Z–product was
vinylcarbazole. This regioselective coupling method has yielded novel
observed when a solution of 3 in THF was irradiated with violet LEDs
conjugated structures, paving the way for advancements in electronic
(Kessil 390 nm) for 4 h. Although compound 3 represents an enamine
materials. The resulting conjugated enamine products exhibit high
structure, its hydrostability was remarkable as 3 was fully recovered
fluorescence quantum yields in the blue-to-green spectrum, efficient
after treatment with aqueous 1 M HCl in DCM at room temperature
photoisomerization, and remarkable hydrostability. These properties
for 15 h. A classical enamine, 1-(cyclohex-1-en-1-yl)pyrrolidine,
underscore
underwent thorough hydrolysis under the same aqueous condition.
demonstrating the unique synthetic capabilities of iron catalysis in
These results suggest the application of the cross-coupling products
accessing
as photo-responsive materials with high moisture resistance.
challenging to synthesize.
Scheme 2. Photoresponsivity and hydrostability of 3.
Experimental Section
(a)
Ph
complex
in
conjugated
electronic
structures
device
that
applications,
are
otherwise
General Information
N
N
potential
S
violet LEDs (390 nm)
S
Ph
their
THF, rt, 4 h
All air or moisture sensitive reactions were performed in a dry
3-Z
(E:Z = 1: 14)
99% yield
3-E
(E:Z = > 20:1)
reaction vessel under argon atmosphere. Air or moisture sensitive
liquids and solutions were transferred with syringe or Teflon cannula.
(b)
Ph
1 M HCl aq.
S
N
DCM, rt, 15 h
The water content of solvents was confirmed to be less than 30 ppm
3
98% recovery
(E:Z = > 20:1)
by Karl-Fischer titration performed with MKC-210 (Kyoto Electronics
Manufacturing Co., Ltd.). Analytical thin-layer chromatography (TLC)
3
(E:Z = > 20:1)
was performed with a glass plate coated with 0.25mm 230-400 mesh
silica gel containing a fluorescent indicator. Organic solutions were
Conclusions
evacuated with a diaphragm pump through a rotary evaporator. Flash
In conclusion, this study presents the development of C–H/C–H
column chromatography was performed using either Kanto Chemical
couplings between thiophenes and N-vinylcarbazole, highlighting the
silica gel 60N or Biotage® Sfär Silica HC D as described by Still et al.[28]
6
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Preparative recycling gel permeation chromatography (GPC) was
for spectrochemical analysis was purchased from FUJIFILM Wako Pure
performed with LC-92XX II NEXT instrument (Japan Analytical Industry
Chemical Co. and used as received.
Co., Ltd.) equipped with JAIGEL-2HR polystyrene columns using
Computational Details
chloroform as an eluent at the flow rate of 7.5 mL/min. LEDs for
Theoretical calculations were performed using a Gaussian 16
reaction were purchased from Kessil and used with a maximum
software package.[30] Geometry optimization and gas-phase energy
intensity.
calculations were performed at the level of B3LYP/6-31G(d,p).
Gas chromatography (GC) was performed with GC-2014
instrument (Shimadzu Co.) equipped with an ULBON HR-1 (0.25 mm
A Representative Procedure for the Investigation of Reaction
I.D. x 25 mL, 0.25 µm, Shinwa Chemical Industries, Ltd.) capillary
Parameters
column. Mass spectra (GC-MS) were taken with Parvum 2 instrument
(Shimadzu Co.). High-resolution mass spectra (HRMS) were taken with
In an oven-dried Schlenk tube was added 2-phenylthiophene
LCMS-IT-TOF (Shimadzu Co.) using reserpine (MW 608.2734) as an
(32 mg, 0.20 mmol), N-vinylcarbazole (58 mg, 0.30 mmol), TP (14 mg,
internal standard. Analytical GPC was performed with Prominence
0.022 mmol), and a THF solution of Fe(acac)3 (0.067 mol/L, 0.30 mL,
instrument (Shimadzu Co.) equipped with a KF-805L (Shodex) column
0.020 mmol). Then, a toluene solution of AlMe3 (2.0 mol/L, 0.30 mL,
at 40 °C using chloroform as an eluent at the flow rate of 1.0 mL/min.
0.60 mmol) was added by rinsing the wall of the Schlenk tube at room
Calibration curves were obtained with ReadyCal Kit (Polymer
temperature. Diethyl oxalate (54 µL, 0.40 mmol) was added and the
Standards Service, GmbH) standard polystyrenes. Melting points of
reaction mixture was stirred at 50 °C for 15 h. The reaction mixture was
solid compounds were measured on a Mel-Temp capillary melting-
cooled to room temperature, diluted with toluene (1 mL), quenched
point apparatus and were uncorrected. Nuclear magnetic resonance
carefully with methanol (0.1 mL) and a saturated aqueous solution of
(NMR) spectra were taken with ECZ-500 (JEOL, Ltd.) at room
potassium sodium tartrate (1 mL). The reaction mixture was diluted
temperature unless otherwise noted and reported in parts per million
with toluene until all the products are dissolved and was stirred
(ppm). 1H NMR spectra were internally referenced to tetramethylsilane
vigorously until clear phase separation was observed. Tridecane (30
(0.00 ppm), CHCl3 (7.26 ppm), CHDCl2 (5.32 ppm), or C2HDCl4 (5.97
µL) was added as an internal standard and a portion of the organic
ppm). 13C NMR spectra were internally referenced to tetramethylsilane
layer was passed through a pad of Florisil and analyzed by GC.
(0.0 ppm), CDCl3 (77.0 ppm), CD2Cl2 (53.8 ppm), or C2D2Cl4 (73.8 ppm).
A General Procedure for Twofold Alkenylation
Unless otherwise noted, reagents were purchased from Tokyo
Chemical Industry Co., Ltd., Sigma-Aldrich Co., LCC, FUJIFILM Wako
In an oven-dried Schlenk tube was added a thiophene (0.20
Pure Chemical Co., and other commercial suppliers and were used as
mmol), an enamine (0.60 mmol), TP (28 mg, 0.044 mmol), and a THF
received.
were
solution of Fe(acac)3 (0.067 mol/L, 0.60 mL, 0.040 mmol). Then, a
purchased from KANTO Chemical Co., Inc. and purified prior to use by
toluene solution of AlMe3 (2.0 mol/L, 0.60 mL, 1.2 mmol) was added
a solvent purification system (GlassContour) equipped with columns
by rinsing the wall of the Schlenk tube. Diethyl oxalate (108 µL, 0.80
of activated alumina and supported copper catalyst.[ 29 ] Fe(acac)3
mmol) was added and the reaction mixture was stirred at 50 °C for 15
(99.9% trace metal basis) was purchased from Sigma-Aldrich Co., LCC
h. The reaction mixture was cooled to room temperature, diluted with
and used as received. Diethyl oxalate was purchased from Tokyo
toluene (2 mL), and quenched carefully with methanol (0.1 mL) and a
Chemical Industry Co., degassed by Freeze-Pump-Thaw cycling for
saturated aqueous solution of potassium sodium tartrate (2 mL). The
three times, dried with molecular sieves 4Å and kept in a storage flask.
reaction mixture was further diluted with toluene and stirred
Thiophene substrates and trisphosphine ligands were synthesized
vigorously until clear phase separation was observed. The aqueous
according to the literature.[12]
layer was extracted with toluene (5 mL x 3) and the combined organic
Anhydrous
tetrahydrofuran
and
diethyl
ether
Absorption spectra (ca. 1.0 × 10–5 M in dichloromethane) were
layers were passed through a pad of Celite. The solvent was removed
measured with a JASCO V-670 spectrometer. Fluorescence spectra (ca.
under reduced pressure and the crude product was purified by silica
1.0 × 10–6 M or ca. 1.0 × 10–7 M in dichloromethane) were measured
gel chromatography (hexane/dichloromethane gradient) and/or gel
with a JASCO FP-8500 spectrometer. Absolute photoluminescence
permeation chromatography (toluene). E/Z isomers could not be
quantum yields were measured with Hamamatsu Photonics C9920–02
separated and E/Z ratios were determined by integration of the 1H
spectrometer equipped with an integrating sphere. Dichloromethane
NMR spectra. Note: Exposure of the crude reaction mixtures to strong
7
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room light should be avoided to prevent E to Z isomerization of the
(8). The title compound was obtained as a yellow solid (94 mg, 40%
coupling product.
yield, E:Z = > 20:1). The reaction was performed on a 0.20 mmol scale
9,9'-((1E,1'E)-((9,9-dioctyl-9H-fluorene-2,7-
and
the
crude
product
silica
purified
gel
by
gel
chromatography
permeation
diyl)bis(thiophene-5,2-diyl))bis(ethene-2,1-diyl))bis(9H-
chromatography
carbazole) (5). The title compound was obtained as an orange solid
dichloromethane = 9:1 to 4:1). M.p. 234–235 °C (dichloromethane). 1H-
(42 mg, 44% yield, E:Z = > 20:1). The reaction was performed on a 0.10
NMR (500 MHz, CDCl3): 8.11 (d, J = 7.7 Hz, 4H), 7.78 (d, J = 8.3 Hz, 4H),
mmol scale and the crude product was purified by gel permeation
7.74 (d, J = 14.3 Hz, 2H), 7.56–7.52 (m, 4H), 7.37–7.34 (m, 6H), 7.30 (d,
1
and
was
(hexane:
chromatography. M.p. 197–199 °C (toluene). H-NMR (500 MHz,
J = 14.3 Hz, 2H), 4.22 (d, J = 5.5 Hz, 4H), 1.98–1.90 (m, 2H), 1.74–1.65
CDCl3): 8.11 (d, J = 7.7 Hz, 4H), 7.76 (d, J = 8.0 Hz, 4H), 7.72 (d, J = 7.9
(m, 4H), 1.50–1.20 (m, 60H), 0.83–0.80 (m, 12H).
Hz, 2H), 7.70 (d, J = 14.4 Hz, 2H), 7.65 (dd, J = 7.9, 1.4 Hz, 2H), 7.60 (d,
CDCl3): 143.9, 140.1, 139.3, 132.2, 128.3, 126.5, 124.9, 124.4, 121.2,
J = 1.4 Hz, 2H), 7.55–7.51 (m, 4H), 7.36–7.33 (m, 6H), 7.21 (d, J = 14.4
120.4, 118.6, 112.9, 110.7, 76.5, 39.2, 31.9, 31.9, 31.3 (two signals
Hz, 2H), 7.08 (d, J = 3.5 Hz, 2H), 2.08–2.05 (m, 4H), 1.20–1.09 (m, 20H),
overlapped), 30.2 (two signals overlapped), 29.8, 29.8, 29.7, 29.7, 29.4,
13
13
C-NMR (125 MHz,
0.80 (t, J = 7.2 Hz, 6H), 0.76–0.70 (m, 4H). C-NMR (125 MHz, CDCl3):
29.4, 27.0 (two signals overlapped), 22.7, 22.6, 14.1 (two signals
151.8, 142.8, 140.3, 139.6, 139.4, 133.1, 126.4, 126.4, 124.6, 124.2, 123.4,
overlapped). HRMS (APCI+): 1165.7649 ([M+H]+, C78H105N2O2S2+; calc.
122.5, 120.9, 120.4, 120.2, 119.8, 113.5, 110.6, 55.3, 40.5, 31.8, 30.0, 29.2,
1165.7612).
+
29.2, 23.8, 22.6, 14.1. HR-MS (APCI+): 937.4576 ([M+H] ,
C65H65N2S2+;
9,9'-Bis((E)-2-(4-hexyl-5-phenylthiophen-2-yl)vinyl)-
calc. 937.4584).
9H,9'H-3,3'-bicarbazole (9). The title compound was obtained as a
9,9'-((1E,1'E)-((9-(heptadecan-9-yl)-9H-carbazole-2,7-
pale yellow solid (54 mg, 62% yield, E:Z = 10:1). The reaction was
diyl)bis(thiophene-5,2-diyl))bis(ethene-2,1-diyl))bis(9H-
performed on a 0.10 mmol scale using 3.0 equiv of the thiophene, 1.0
carbazole) (6). The title compound was obtained as an orange solid
equiv of the N-vinylcarbazole, 40 mol % of Fe(acac)3, and 44 mol % of
(92 mg, 48% yield, E:Z = > 20:1). The reaction was performed on a 0.20
TP. The crude product was purified by silica gel chromatography
mmol scale and the crude product was purified by gel permeation
(hexane/dichloromethane
1
gradient).
M.p.
159–165
°C
1
chromatography. M.p. 70–72 °C (toluene). H-NMR (500 MHz, C2D2Cl4,
(dichloromethane). H-NMR (500 MHz, CDCl3): 8.40 (d, J = 1.3 Hz, 2H),
120 °C): 8.13–8.09 (m, 6H), 7.77–7.75 (m, 6H), 7.71 (d, J = 14.3 Hz, 2H),
8.19 (d, J = 2.8 Hz, 2H), 7.87 (dd, J = 8.3, 1.8 Hz, 2H), 7.82 (d, J = 8.6 Hz,
7.57–7.53 (m, 6H), 7.39–7.35 (m, 6H), 7.24 (d, J = 14.3 Hz, 2H), 7.16 (d,
2H), 7.74 (d, J = 8.3 Hz, 2H), 7.65 (d, J = 14.3 Hz, 2H), 7.55–7.50 (m, 6H),
J = 3.7 Hz, 2H), 4.71–4.66 (m, 1H), 2.42–2.38 (m, 2H), 2.12–2.08 (m, 2H),
7.46–7.43 (m, 4H), 7.37–7.34 (m, 4H), 7.19 (d, J = 14.3 Hz, 2H), 7.01 (s,
13
1.37–1.24 (m, 24H), 0.86 (t, J = 7.2 Hz, 6H). C-NMR (125 MHz, CDCl3):
2H), 2.67 (t, J = 8.0 Hz, 4H), 1.69–1.63 (m, 4H), 1.37–1.28 (m, 12H), 0.88
143.5 (br), 139.6 (br), 139.4, 126.5, 126.4, 124.1, 123.5, 122.4 (br), 120.9,
(t, J = 7.2 Hz, 6H). 13C-NMR (125 MHz, CDCl3): 139.9, 139.4, 138.5, 138.3,
120.4, 117.3 (br), 113.7, 110.6, 108.5 (br), 105.9 (br), 56.5, 33.8, 31.7,
135.8, 134.7, 134.6, 129.2, 128.6, 128.0, 127.4, 126.5, 126.0, 124.7, 124.2,
29.4, 29.3, 29.2, 26.8, 22.6, 14.1. (Multiple broad signals were observed
122.3, 120.9, 120.5, 118.9, 113.6, 110.9, 110.7, 31.6, 30.9, 29.2, 28.8, 22.6,
+
14.1. HR-MS (APCI+): 869.3956 ([M+H]+, C60H57N2S2+; calc. 869.3958).
because of slow rotation of bonds.) HR-MS (APCI+): 952.4705 ([M+H] ,
C65H66N3S2+; calc. 952.4693).
5,11-Bis((E)-2-(4-hexyl-5-phenylthiophen-2-yl)vinyl)-5,11-
N,N-bis(4-(5-((E)-2-(9H-carbazol-9-yl)vinyl)thiophen-2-
dihydroindolo[3,2-b]carbazole (10). The title compound was
yl)phenyl)-2,4,6-trimethylaniline (7). The title compound was
obtained as a yellow solid (45 mg, 57% yield, E:Z = 4:1). The reaction
obtained as an orange oil (93 mg, 56% yield, E:Z = 20:1). The reaction
was performed on a 0.10 mmol scale using 3.0 equiv of the thiophene,
was performed on a 0.20 mmol scale and the crude product was
1.0 equiv of the N-vinylcarbazole, 40 mol % of Fe(acac)3, and 44 mol %
1
purified by gel permeation chromatography. H-NMR (500 MHz,
of TP. The crude product was purified by silica gel chromatography
CD2Cl2): 8.03–8.01 (m, 4H), 7.68–7.66 (m, 4H), 7.57 (d, J = 14.4 Hz, 2H),
(hexane/dichloromethane
gradient).
M.p.
148–152
°C
1
7.45–7.41 (m, 8H), 7.26–7.22 (m, 4H), 7.12–7.09 (m, 4H), 6.97–6.92 (m,
(dichloromethane). H-NMR (500 MHz, CD2Cl2): 8.33 (s, 2H), 8.22 (d, J
13
8H), 2.27 (s, 3H), 1.97 (s, 6H). C-NMR (125 MHz, CD2Cl2): 145.5, 142.5,
= 7.8 Hz, 2H), 7.78–7.73 (m, 4H), 7.56–7.50 (m, 6H), 7.49–7.43 (m, 4H),
139.7, 139.0, 137.8, 137.7, 130.3, 127.3, 126.9, 126.7, 126.6, 125.2, 124.4,
7.39–7.33 (m, 4H), 7.26 (d, J = 13.5 Hz, 2H), 7.08 (s, 2H), 2.62 (t, J = 8.0
122.6, 122.5, 121.2, 120.6, 120.2, 113.9, 111.0, 21.1, 18.6. HR-MS
Hz, 4H), 1.64–1.57 (m, 4H), 1.31–1.21 (m, 12H), 0.81 (t, J = 6.9 Hz, 6H).
(APCI+): 834.2981 ([M+H]+, C57H44N3S2+; calc. 834.2971).
13
C-NMR (125 MHz, CD2Cl2): 140.8, 139.9, 139.0, 135.8, 135.0, 129.4,
9,9'-((1E,1'E)-(4,8-bis((2-octyldodecyl)oxy)benzo[1,2-b:4,5-
128.9, 128.3, 127.7, 127.0, 125.2, 124.6, 124.4, 123.0, 121.0, 120.6, 113.1,
b']dithiophene-2,6-diyl)bis(ethene-2,1-diyl))bis(9H-carbazole)
8
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110.9, 101.6, 32.0, 31.3, 29.5, 29.1, 23.0, 14.2. HR-MS (APCI+): 793.3652
122.6, 120.4, 120.3, 119.8, 110.9. HR-MS (APCI+): 352.1160 ([M+H]+,
([M+H]+, C54H53N2S2+; calc. 793.3645).
C24H18NS+; calc. 352.1154).
A Procedure for the Synthesis of an End-Capped Oligomer
A Procedure for Treatment of Compound 3 with Acid
In an oven-dried Schlenk tube was added 2,2'-(9,9-dioctyl-9H-
To a mixture of (E)-9-(2-(5-phenylthiophen-2-yl)vinyl)-9H-
fluorene-2,7-diyl)dithiophene (111 mg, 0.20 mmol), 9-vinyl-9H-
carbazole (7.0 mg, 0.020 mmol) in dichloromethane (0.2 mL) was
carbazole (9.7 mg, 0.050 mmol), TP (28 mg, 0.044 mmol), and a THF
added an aqueous solution of HCl (1 mol/L, 0.2 mL) and stirred at room
solution of Fe(acac)3 (0.067 mol/L, 0.60 mL, 0.040 mmol). Then, a
temperature for 15 h. The aqueous layer was extracted with
toluene solution of AlMe3 (2.0 mol/L, 0.60 mL, 1.2 mmol) was added
dichloromethane (1 mL x 3) and the combined organic layers were
by rinsing the wall of the Schlenk tube. Diethyl oxalate (108 µL, 0.80
dried over Na2SO4. The solvent was removed under reduced pressure
mmol) was added and the reaction mixture was stirred at 70 °C for 24
and the crude product was analyzed by 1H NMR using 1,1,2,2-
h. The reaction mixture was cooled to room temperature and
tetrachloroethane as an internal standard. (E)-9-(2-(5-phenylthiophen-
quenched carefully with methanol (0.1 mL) and a saturated aqueous
2-yl)vinyl)-9H-carbazole was recovered in 98% yield with retention of
solution of potassium sodium tartrate (2 mL). The reaction mixture was
E configuration.
diluted with chloroform (6 mL) and was stirred vigorously until clear
Supporting Information
phase separation was observed. The aqueous layer was extracted with
chloroform (20 mL) and the organic layer was passed through a pad of
The authors have provided the NMR spectra and GPC chromatogram
Celite and Florisil. The solvent was removed under reduced pressure
of the products and the cartesian coordinates of the model
and
compounds in the Supporting Information.
the
crude
product
was
purified
by
gel
permeation
chromatography (chloroform) to afford the product as a yellow orange
Acknowledgements
solid (50 mg, 41%, E:Z = 16:1). 1H-NMR (500 MHz, CDCl3): 8.11 (d, J =
7.8 Hz, 0.4H), 7.77–7.51 (m, 7H), 7.36–7.29 (m, 2.6H), 7.25–7.08 (m,
2.2H), 2.15–2.00 (br, 4H), 1.20–1.08 (br, 20H), 0.82–1.65 (br, 10H).
We thank Mitsubishi Chemical Corporation for partial financial support.
13
C-
This research is supported by MEXT KAKENHI grant number 19H05459
NMR (125 MHz, CDCl3): 151.8, 143.8, 140.3, 139.4, 136.5, 132.9, 126.4,
(to E.N.) and JSPS KAKENHI grant number 19K15555 (to R.S.). The
124.6, 124.5, 124.2, 123.7, 121.0, 120.4, 120.2, 119.7, 110.6, 55.3, 40.4,
computation was performed at the Research Center for Computational
31.8, 30.0, 29.2, 29.2, 23.7, 22.6, 14.1. (Signals of the quaternary carbons
Science, Okazaki, Japan (Project: 21-IMS-C140).
of the termini carbazoles were not observable because of the low
Author Contribution Statement
intensity.) Mn = 6.7 kg/mol, Mw = 10.9 kg/mol, Mw/Mn = 1.62, DP = 11.
1
DP was determined as 10 by integration of the H NMR spectrum,
T.D. conducted the experiments to study the scope and the application.
which is in good correspondence with the DP value obtained by
The manuscript was written with the contributions of all authors.
analytical GPC.
Entry for the Table of Contents
A Procedure for E to Z Isomerization
(Z)-9-(2-(5-phenylthiophen-2-yl)vinyl)-9H-carbazole (3-Z).
S
A mixture of (E)-9-(2-(5-phenylthiophen-2-yl)vinyl)-9H-carbazole (3-E,
π
+
8.7 mg, 0.020 mmol) in THF (0.50 mL) was irradiated with violet LED
N
S
cat. Fe(III)
cat. trisphosphine
N
AlMe3
DEO
(390 nm, 52 W) at room temperature for 4 h. The crude reaction
S
π
S
n
N
n = 1 or more
mixture was passed through a pad of silica gel using ethyl acetate as
an eluent and the solvent was removed under reduced pressure to
Twitter
afford the product as a pale yellow solid (6.9 mg, 99% yield, E:Z = 1:
14). M.p. 143–146 °C (ethyl acetate). 1H-NMR (500 MHz, CDCl3): 8.14–
Twofold alkenylation of thiophenes with N-vinylcarbazole via iron-
8.12 (m, 2H), 7.42–7.39 (m, 2H), 7.32–7.27 (m, 6H), 7.24–7.21 (m, 2H),
catalyzed regioselective C–H/C–H coupling is described by Takahiro
7.18–7.15 (m, 1H), 7.06 (d, J = 4.0 Hz, 1H), 6.98 (d, J = 8.2 Hz, 1H), 6.89
Doba, Rui Shang, and Eiichi Nakamura.
13
(d, J = 4.0 Hz, 1H), 6.72 (d, J = 8.2 Hz, 1H). C-NMR (125 MHz, CDCl3):
145.8, 139.6, 136.0, 133.8, 130.1, 128.7, 127.6, 126.0, 125.7, 124.2, 123.3,
9
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References
[ 1 ] P. F. van Hutten, J. Wildeman, A. Meetsma, G. Hadziioannou,
Methylaluminum and Tridentate Phosphine Ligand’, J. Am. Chem. Soc.
‘Molecular
2016, 138, 10132–10135.
Packing
in
Unsubstituted
Semiconducting
Phenylenevinylene Oligomer and Polymer’, J. Am. Chem. Soc. 1999,
[15] R. Shang, L. Ilies, E. Nakamura, ‘Iron-Catalyzed Directed C(sp2)–H
121, 5910–5918.
and C(sp3)–H Functionalization with Trimethylaluminum’, J. Am. Chem.
[2] M. Chen, W. Sato, R. Shang, E. Nakamura, ‘Iron-Catalyzed Tandem
Soc. 2015, 137, 7660–7663.
Cyclization of Diarylacetylene to a Strained 1,4-Dihydropentalene
[ 16 ] J. Norinder, A. Matsumoto, N. Yoshikai, E. Nakamura, ‘Iron-
Framework for Narrow-Band-Gap Materials’, J. Am. Chem. Soc. 2021,
Catalyzed Direct Arylation through Directed C−H Bond Activation’, J.
143, 6823–6828.
Am. Chem. Soc. 2008, 130, 5858–5859.
[3] H. Tsuji, E. Nakamura, ‘Carbon-Bridged Oligo(phenylene vinylene)s:
[17] T. Doba, S. Fukuma, R. Shang, E. Nakamura, ‘Versatile Synthesis of
A de Novo Designed, Flat, Rigid, and Stable π-Conjugated System’, Acc.
Trisphosphines Bearing Phenylene and Vinylene Backbones Useful for
Chem. Res. 2019, 52, 2939–2949.
Metal Catalysis and Materials Applications’, Synthesis 2023, 55, 1690–
[4] H. Katayama, M. Nagao, T. Nishimura, Y. Matsui, K. Umeda, K.
1699.
Akamatsu, T. Tsuruoka, H. Nawafune, F. Ozawa, ‘Stereocontrolled
[18] H. Sirringhaus, T. Kawase, R. H. Friend, T. Shimoda, M. Inbasekaran,
Synthesis and Optical Properties of All-cis Poly(phenylene vinylenes)
W. Wu, E. P. Woo, ‘High-Resolution Inkjet Printing of All-Polymer
(PPVs): A Method for Direct Patterning of PPVs’, J. Am. Chem. Soc. 2005,
Transistor Circuits’, Science 2000, 290, 2123–2126.
127, 4350–4353.
[19 ] S. Wakim, N. Blouin, E. Gingras, Y. Tao, M. Leclerc, ‘Poly(2,7-
[5] D. Gendron, M. Leclerc, ‘New conjugated polymers for plastic solar
carbazole) Derivatives as Semiconductors for Organic Thin-Film
cells’, Energy Environ. Sci. 2011, 4, 1225.
Transistors’, Macromol. Rapid Commun. 2007, 28, 1798–1803.
[6] I. Moritani, Y. Fujiwara, ‘Aromatic substitution of styrene-palladium
[ 20 ] H. Lin, T. Doba, W. Sato, Y. Matsuo, R. Shang, E. Nakamura,
chloride complex’, Tetrahedron Lett. 1967, 8, 1119–1122.
‘Triarylamine/Bithiophene
[7] Y. Fujiwara, I. Moritani, S. Danno, R. Asano, S. Teranishi, ‘Aromatic
Character as Hole-Transporting Material for Perovskite Solar Cells’,
substitution of olefins. VI. Arylation of olefins with palladium(II)
Angew. Chem. Int. Ed. 2022, 61, e202203949.
acetate’, J. Am. Chem. Soc. 1969, 91, 7166–7169.
[21] P. Dutta, J. Kim, S. H. Eom, W.-H. Lee, I. N. Kang, S.-H. Lee, ‘An
[8] H. von Schenck, B. Åkermark, M. Svensson, ‘Electronic Control of
Easily Accessible Donor−π-Acceptor-Conjugated Small Molecule from
the Regiochemistry in the Heck Reaction’, J. Am. Chem. Soc. 2003, 125,
a
3503–3508.
Solution-Processed Organic Solar Cells’, ACS Appl. Mater. Interfaces
[9] T. Doba, R. Shang, E. Nakamura, ‘Iron-Catalyzed C–H Activation for
2012, 4, 6669–6675.
Heterocoupling and Copolymerization of Thiophenes with Enamines’,
[22] H. Sasabe, N. Toyota, H. Nakanishi, T. Ishizaka, Y. Pu, J. Kido, ‘3,3′-
J. Am. Chem. Soc. 2022, 144, 21692–21701.
Bicarbazole-Based
[ 10 ] R. Shang, L. Ilies, E. Nakamura, ‘Iron-Catalyzed C–H Bond
Phosphorescent OLEDs with Extremely Low Driving Voltage’, Adv.
Activation’, Chem. Rev. 2017, 117, 9086–9139.
Mater. 2012, 24, 3212–3217.
[ 11 ] T. Doba, T. Matsubara, L. Ilies, R. Shang, E. Nakamura,
[23] R. Shang, Z. Zhou, H. Nishioka, H. Halim, S. Furukawa, I. Takei, N.
‘Homocoupling-free iron-catalysed twofold C–H activation/cross-
Ninomiya, E. Nakamura, ‘Disodium Benzodipyrrole Sulfonate as
couplings of aromatics via transient connection of reactants’, Nat.
Neutral Hole-Transporting Materials for Perovskite Solar Cells’, J. Am.
Catal. 2019, 2, 400–406.
Chem. Soc. 2018, 140, 5018–5022.
[12] T. Doba, L. Ilies, W. Sato, R. Shang, E. Nakamura, ‘Iron-catalysed
[ 24 ] M. I. Mangione, R. A. Spanevello, D. Minudri, D. Heredia, L.
regioselective thienyl C–H/C–H coupling’, Nat. Catal. 2021, 4, 631–638.
Fernandez,
[13] D. Shriver, P. Atkins, T. Overton, J. Rourke, M. Weller, Armstrong,
Functionalizaed Carbazole End-Capped Dendrimers. Formation of
F. Shriver & Atkins Inorganic Chemistry; Oxford University Press: Oxford,
Conductive Films’, Electrochimica Acta 2016, 207, 143–151.
2006.
[ 25 ] S.-H. Hsiao, Y.-Z. Chen, ‘Electrosynthesis of redox-active and
[ 14 ] R. Shang, L. Ilies, E. Nakamura, ‘Iron-Catalyzed Ortho C–H
electrochromic polymer films from triphenylamine-cored star-shaped
Methylation of Aromatics Bearing a Simple Carbonyl Group with
molecules end-capped with arylamine groups’, European Polymer
Copolymer
with
4,8-Dialkoxybenzo[1,2-b :4,5-b′]dithiophene
L.
Host
Otero,
Journal 2018, 99, 422–436.
10
This article is protected by copyright. All rights reserved.
Materials
F.
Fungo,
for
Enhanced
Unit
for
Quinoidal
Efficient
High-Efficiency
‘Electropolimerization
Blue
of
Accepted Manuscript
HELVETICA
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Helvetica Chimica Acta
[26] F. Liu, J. Zou, Q. He, C. Tang, L. Xie, B. Peng, W. Wei, Y. Cao, W.
[30] Gaussian 16, Revision C.01, M. J. Frisch, G. W. Trucks, H. B. Schlegel,
Huang, ‘Carbazole end-capped pyrene starburst with enhanced
G. E. Scuseria, M. A. Robb, J. R. Cheeseman, G. Scalmani, V. Barone, G.
electrochemical stability and device performance’, J. Polym. Sci. A
A. Petersson, H. Nakatsuji, X. Li, M. Caricato, A. V. Marenich, J. Bloino,
Polym. Chem. 2010, 48, 4943–4949.
B. G. Janesko, R. Gomperts, B. Mennucci, H. P. Hratchian, J. V. Ortiz, A.
[27] H.-J. Son, W.-S. Han, S. J. Han, C. Lee, S. O. Kang, ‘Electrochemically
F. Izmaylov, J. L. Sonnenberg, D. Williams-Young, F. Ding, F. Lipparini,
Active Dendrimers for the Manufacture of Multilayer Films:
F. Egidi, J. Goings, B. Peng, A. Petrone, T. Henderson, D. Ranasinghe, V.
Electrochemical Deposition or Polymerization Process by End-Capped
G. Zakrzewski, J. Gao, N. Rega, G. Zheng, W. Liang, M. Hada, M. Ehara,
Triarylamine or Carbazole Dendrimer’, J. Phys. Chem. C 2010, 114,
K. Toyota, R. Fukuda, J. Hasegawa, M. Ishida, T. Nakajima, Y. Honda, O.
1064–1072.
Kitao, H. Nakai, T. Vreven, K. Throssell, Jr. J. A. Montgomery, J. E. Peralta,
[28] W. C. Still, M. Kahn, A. Mitra, ‘Rapid chromatographic technique
F. Ogliaro, M. J. Bearpark, J. J. Heyd, E. N. Brothers, K. N. Kudin, V. N.
for preparative separations with moderate resolution’, J. Org. Chem.
Staroverov, T. A. Keith, R. Kobayashi, J. Normand, K. Raghavachari, A. P.
1978, 43, 2923–2925.
Rendell, J. C. Burant, S. S. Iyengar, J. Tomasi, M. Cossi, J. M. Millam, M.
[29] A. B. Pangborn, M. A. Giardello, R. H. Grubbs, R. K. Rosen, F. J.
Klene, C. Adamo, R. Cammi, J. W. Ochterski, R. L. Martin, K. Morokuma,
Timmers, ‘Safe and Convenient Procedure for Solvent Purification’,
O. Farkas, J. B. Foresman, D. J. Fox, Gaussian, Inc., Wallingford CT, 2016.
Organometallics 1996, 15, 1518–1520.
11
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15222675, ja, Downloaded from https://onlinelibrary.wiley.com/doi/10.1002/hlca.202300210 by Cochrane Japan, Wiley Online Library on [20/12/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License
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Helvetica Chimica Acta