Synthesis and Characterization of Carbazole-Linked Porphyrin Tweezers

Article abstract of DOI:10.1002/chem.201501619

Herein the synthesis, spectroscopic characterization, two-photon absorption and electrochemical properties of 3,6-disubstituted carbazole tweezers is reported. A dimer resulting from a Glaser homocoupling was isolated during a Sonogashira coupling reaction between a diethynyl-carbazole spacer and a 5-bromo-triarylporphyrin and the properties of this original compound were compared with the 3,6-disubstituted carbazole bisporphyrin tweezers. The dyads reported herein present a two-photon absorption maximum at 920nm with two-photon absorption cross-section in the 1200GM range. Despite a strong linear absorption in the Soret region and moderate fluorescence quantum yield, they both lead to a high brightness reaching 30000m^-1cm^-1.

Full text of DOI:10.1002/chem.201501619

DOI: 10.1002/chem.201501619
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Electrochemistry |Hot Paper|
Synthesis and Characterization of Carbazole-Linked Porphyrin
Tweezers
Yi Chang,[a] ClØment Michelin,[a] LØo Bucher,[a] Nicolas Desbois,[a] Claude P. Gros,*[a]
SØbastien Piant,[b] FrØdØric Bolze,*[b] Yuanyuan Fang,[c] Xiaoqin Jiang,[c] and Karl M. Kadish*[c]
Abstract: Herein the synthesis, spectroscopic characteriza-
tion, two-photon absorption and electrochemical properties
of 3,6-disubstituted carbazole tweezers is reported. A dimer
resulting from a Glaser homocoupling was isolated during
a Sonogashira coupling reaction between a diethynyl-carba-
zole spacer and a 5-bromo-triarylporphyrin and the proper-
ties of this original compound were compared with the
3,6-disubstituted carbazole bisporphyrin tweezers. The
dyads reported herein present a two-photon absorption
maximum at 920 nm with two-photon absorption cross-sec-
tion in the 1200 GM range. Despite a strong linear absorp-
tion in the Soret region and moderate fluorescence quan-
tum yield, they both lead to a high brightness reaching
30000mÀ1 cmÀ1
.
Introduction
bazole tweezer porphyrin compound have never been report-
ed. This is addressed in the current study with the two tweezer
ZnII bis-porphyrin compounds 1a and 1b the structures of
which are shown in Scheme 1, along with several related mole-
cules which were also examined for comparison with the bis-
porphyrins.
In recent years, porphyrin tweezers have attracted the interest
of synthetic chemists because of the possibility to fine-tune
the electrochemical and photophysical properties of these spe-
cies with an aim towards developing their use for application
in the areas of optoelectronic derivatives,[1] photovoltaic devi-
ces,[2] nonlinear optics[3] and biology.[4] A number of conjugated
molecules have been used as bridges to link porphyrin macro-
cycles to each other, forming dimers with different geometries,
varying from co-facial to linear. Of particular interest are
bridges containing nitrogen heterocycles such as diketopyrro-
lopyrrole and carbazoles.[1,5]
Results and Discussion
The target structures of tweezers 1a and 1b are shown in
Scheme 1. The alkyl substituent on the nitrogen atom of 1a
was introduced to increase the solubility. A bisporphyrin linked
by a carbazole containing the triethylene glycol unit was syn-
thesized (1b) in order to investigate how this group would
affect the compound’s optical and electronic properties. The
utilized synthetic route for obtaining the spacers and tweezers
are shown in Scheme 2 and Scheme 3. Diethynylcarbazole
tweezers 1a and 1b were obtained by a one-pot coupling of
the bromoporphyrin precursor with the diethynyl-carbazole
central core.
Porphyrin dimers with 2,7-carbazole linkers were synthesized
by Senge and co-workers who examined these as light-emit-
ting devices with efficient red electroluminescence.[1] These
2,7-disubstituted carbazole derivatives were shown to exhibit
efficient red electroluminescence. The two-photon absorption
properties of a bisporphyrin linked by carbazole at the 3,6-po-
sitions were also recently described in the 800–900 nm
range.[5f] However, to our knowledge, the two-photon absorp-
tion and electrochemical properties of a 3,6-disubstituted car-
Palladium-catalyzed coupling of the 5-bromo-10,15,20-tri-
phenylporphyrin[6] (1.0 equiv) and the carbazolethynylene unit
5a or 5b (1.0 equiv) afforded 1a and 1b in 13 and 29% yield,
respectively. Formation of byproduct 9 was also observed. The
compounds were purified and fully characterized by mass
spectrometry, 1H NMR and 13C NMR spectroscopy in CHCl3.
Scheme 4 shows the coupling reaction, which led to the bis-
carbazole porphyrin ethynylene dimer 9. This homocoupling
reaction, known as the Glaser reaction,[7] is frequently encoun-
tered during Sonogashira carbonÀcarbon coupling reactions[8]
and from a mechanistic point of view has many similarities
with the palladium/alkyne reaction except in the last step of
the catalytic cycle. The bisporphyrin 9 was isolated in 11 %
yield and fully characterized by 1H NMR spectroscopy and
HRMS MALDI/TOF mass spectrometry. A perfect match be-
[a] Dr. Y. Chang, Dr. C. Michelin, L. Bucher, Dr. N. Desbois, Prof. Dr. C. P. Gros
Institut de Chimie MolØculaire de l’UniversitØ de Bourgogne (UMR 6302)
9 Avenue Alain Savary, BP 47870, 21078 Dijon Cedex (France)
E-mail: claude.gros@u-bourgogne.fr
[b] S. Piant, Dr. F. Bolze
Conception et Application des MolØcules Bioactives (UMR 7199)
FacultØ de Pharmacie, 74 route du Rhin, 67401 Illkirch (France)
E-mail: frederic.bolze@unistra.fr
[c] Dr. Y. Fang, X. Jiang, Prof. Dr. K. M. Kadish
Department of Chemistry
University of Houston, Houston, TX 77204-5003 (USA)
E-mail: kadish@central.uh.edu
Supporting information for this article is available on the WWW under
http://dx.doi.org/10.1002/chem.201501619.
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Scheme 2. Synthesis of diethynylcarbazole spacers 5a and 5b. a) RBr, tetra-
butylammonium bromide (TBAB), NaOH, toluene; b) NIS, AcOH, CHCl3, RT,
6 h; c) (trimethylsilyl)acetylene, Pd(PPh3)2Cl2, CuI, Et3N, THF, RT, 48 h;
d) NaOH, EtOH, RT, 1 h.
Scheme 1. Structures of the investigated porphyrin and carbazole deriva-
tives.
Scheme 3. Synthesis of diethynyl-carbazole tweezers 1a and 1b. a) Pd(dba)2,
PPh3, CuI, Et3N, pyridine, 808C, overnight.
tween the experimental and the simulated ionic patterns con-
vincingly confirmed the structure of the compound (see the
Supporting Information). For example, the calculated mass of 9
(C122H88N10O6Zn2) is equal to 1916.5466 Da, in agreement with
the experimental value of 1916.5432 Da (corresponding to
[M]+·).
placing ortho-dichlorobenzene (classically used) by a polar ac-
ceptor solvent such as nitrobenzene, the reaction time was re-
duced to 5 h (instead of 14 h) and the coupling product 8b
was obtained in 37% yield (Scheme 5). The coupling of the
porphyrin[9] and the carbazole was achieved through Suzuki
coupling[10] between the porphyrin 8c and the brominated car-
bazole 8b in the presence of the palladium(II) catalyst in
a basic toluene/DMF medium at 808C for 24 h. The substitu-
tion of bromine by iodine, a stronger nucleophile, promotes
oxidative addition to palladium (step 2, Scheme 5). The por-
The experimental conditions were varied to optimize the
coupling reaction between para-dibromobenzene and carba-
zole 1,8-dialdehyde (8a).[5a] The best yield was obtained after
5 h of reflux in nitrobenzene in the presence of crown ether
18-C-6 and copper(I) iodide (1.0 equiv). The use of this more
soluble copper(I) salt (compared to NaI) led to a significant im-
provement in the efficiency of the reaction. Moreover, by re-
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Scheme 5. Synthesis of N-carbazole porphyrin 8. a) 1,4-Dibromobenzene,
CuI, K2CO3, 18-C-6, nitrobenzene, reflux, 5 h; b) NaI, Cs2CO3, [PdCl(h3-C3H5)]2,
PPh3, toluene/DMF, 808C, 24 h.
Scheme 4. Synthesis of carbazole dimer 9.
phyrin-carbazole derivative
(Scheme 5).
8
was isolated in 33% yield
clearly visible on the emission spectrum with Dn=1184 cmÀ1.
These values are comparable with similar reported compounds
bearing an imidazole group at the meso position of the por-
phyrin rings,[5f] but these compounds exhibit a small batho-
chromic shift of 376 cmÀ1 as compared to the currently exam-
ined dyads 1a and 1b.
One- and two-photon photophysics
The two synthesized dimers in Scheme 1 exhibit very similar
absorption and emission photophysical properties (Table 1).
Both porphyrin tweezers possess an intense Soret band at
449 nm, with a slightly higher intensity for 1b than for 1a, and
three lower energy Q bands at 539, 577 and 633/634 nm
(Figure 1). Compared to the parent monomeric alkynyltriaryl
zinc porphyrin 6 (Scheme 1), described by Senge and co-work-
ers,[5e] one can note a significant increase in the absorption effi-
ciency, as expected for conjugated porphyrin dimers (about
400000 and 70000 for the Soret and Q bands, respectively, for
1b/1a as compared to 200000 and 8000 for the monopor-
phyrin). The diyne dimer 9, for its part, exhibits blue shifted
emission bands and lower molecular extinction coefficients, in-
dicating a lower conjugation in the system, and a possible
face-to-face geometry.
The bisporphyrin 1a and 1b both exhibit a similar photolu-
em
max
minescence behavior, with l =643/644 nm and a quantum
yield of 8–8.5%. The excited state lifetime was measured as
1.31 ns for the two compounds. The vibrational progression is
Figure 1. Absorption (solid line) and emission (dashed line) spectra of 1a
(red), 1b (black) and 9 (green) in CH2Cl2 solution.
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crucial role of the substitution pattern of the porphyrinic
moiety on the TPA properties. The diyne molecule 9 showed
very low two-photon absorption cross sections in the 750–
1000 nm region, <25 GM, despite having a diyne linker which
generally leads to a large TPA cross section in porphyrinic
dyads. Indeed, studies on various co-facial bisporphyrin sys-
tems (e.g., (DPO)Zn2, (DPA)Zn2 and (DPX)Zn2 Pacman bispor-
phyrins dyads)[5a] have demonstrated very low TPA cross sec-
tions, similar to simple porphyrin systems with s2 <50 GM,
values close to the TPA properties of a monoporphyrin
system.[12]
Table 1. Photophysical properties of 1a, 1b, 7 and 9 in CH2Cl2 at 298 K.
[11]
[11]
[a][11]
Compound
labs
e
lem
Fem
t
[nm]
[mÀ1 cmÀ1
]
[nm]
[%]
[ns]
1a
449
539
577
634
398000
8500
25000
65500
644
8.1
1.31
1b
449
457000
643
8.5
1.31
(453)[d]
539
9900
577
28500
(584)[d]
633
72000
(642)[d]
monomer 7[b]
429
566
608
204000
8100
5700
3,6-carba-
imidazole[c]
450
651
660
717
15
9
435
448
527
570
619
190000
240000
8000
16000
30000
639
25.0
Scheme 6. Structure of a carbazole-bridged porphyrin dimer.
[a] Using cresyl violet as standard F=56%; [b] ref. [5e]; [c] ref. [5f];
[d] values in pyridine as solvent in bracket.
Electrochemistry and spectroelectrochemistry
Electron-transfer reactions of the investigated tweezer com-
pounds can occur at the conjugated p-ring system of the por-
phyrin macrocycle(s) or, in the case of oxidations, at the elec-
troactive carbazole bridge. In the present study, the exact site
of electron transfer was assigned on the basis of spectroelec-
trochemistry and by comparing oxidation and reduction po-
tentials for the individual redox active parts of the molecule
when measured outside of the dyad.
The two-photon absorption (TPA) properties of 1a and 1b
were investigated by the up-converted fluorescence method
(Figure 2). There is an intense TPA band with an absorption
maximum at 910–920 nm with s2 ꢀ1000 GM and less intense
bands at 830 and 750 nm, with s2 in the 400 GM range. A sig-
nificant contribution from one photon absorption is seen for
wavelengths <750 nm, with a deviation from the quadratic
dependency law characteristic of pure two-photon processes.
A similar system 10 (Scheme 6), with an additional imidazole
group at the 11 position on the porphyrin macrocycle, showed
a stronger TPA band with s2 =720 GM at 830 nm and weaker
bands at 880 nm with s2 =500 GM.[5f] This clearly indicates the
An example of one such comparison is given in Figure 3 for
1a, (TPP)Zn and carbazole b in CH2Cl2 containing 0.1m TBAP.
Porphyrin 1a in CH2Cl2 and 0.1m TBAP exhibits two reduc-
tions at E1/2 =À1.20 and À1.71 V and four oxidations at Ep =
&
^
Figure 2. Two-photon excitation spectra of 1a ( ) and 1b ( ) in CH2Cl2 at
298 K.
Figure 3. Cyclic voltammograms of 1a, (TPP)Zn and carbazole b in CH2Cl2,
0.1m TBAP, scan rate=0.1 VsÀ1
.
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0.74 V and E1/2 =0.92, 1.32 and 1.40 V. Under the same solution
conditions, (TPP)Zn shows two reductions at E1/2 =À1.33 and
À1.72 V and two oxidations at E1/2 =0.84 and 1.16 V. The four
redox processes of (TPP)Zn are all porphyrin ring-centered to
form a porphyrin p anion radical and dianion upon reduction
and a porphyrin p cation radical and dication upon oxidation.
The first reversible reduction of (TPP)Zn at À1.33 V becomes
irreversible when the potential sweep is reversed after the
second reduction and, under these conditions, a new reoxida-
tion peak is observed at Ep =À0.54 V. The carbazole b linker
group is not reduced within the negative potential limit of the
CH2Cl2 solvent but it is irreversibly oxidized at Ep =1.28 V for
a scan rate of 0.1 VsÀ1 and this process is coupled with a reduc-
tion peak at Ep =0.85 V. A similar irreversible oxidation occurs
for carbazoles a and c with Ep located at 1.32 and 1.44 V, re-
spectively, in CH2Cl2 (Table 2).
mately 50% (Figure 3). This suggests that two electrons are ab-
stracted in the first oxidation of 1a to give a bisporphyrin bis-
cation radical followed at a more positive potential by another
electron abstraction to give a triply charged mixed oxidation
state species, which is then further oxidized by one more elec-
tron in the range of +1.32 to +1.40 V. The electroactive carba-
zole linker of 1a is also oxidized at 1.32–1.40 V but it was not
possible to determine if this oxidation occurs before or after
oxidation at the porphyrin p ring system, which occurs in the
same potential region. It is important to point out that the
second oxidation at 0.92 V (1a) or 0.95 V (1b) in CH2Cl2 are
both substantially shifted in a negative direction as compared
to the second oxidation of (TPP)Zn at 1.16 V in the same sol-
vent.
Attempts were made to slow down the chemical reaction
following the first oxidation of 1a but the peak remained irre-
versible at all temperatures from RT to À458C, as shown in Fig-
ure S29 in the Supporting Information. This indicates the oc-
currence of a very fast chemical reaction. Similar redox behav-
ior was observed for 1b in CH2Cl2, with the large separation in
potential between the second and third oxidations being ex-
plained by the presence of two equivalent and interacting
redox centers, as was reported for other porphyrin dyads with
a face-to-face arrangement.[13]
The peak currents for the first oxidation and first reduction
of the bisporphyrin 1a in CH2Cl2 are approximately equal to
each other (Figure 3) and this fact suggests the same number
of electrons transferred in each step, two upon reduction and
two upon oxidation. However, the shape of the current–volt-
age curve for the first oxidation of 1a is consistent with a fast
chemical reaction following a reversible electron transfer (an
electrochemical EC mechanism) and this is followed by
a second reversible oxidation at E1/2 =0.92 V, the peak current
of which is smaller than that of the first process by approxi-
Cyclic voltammograms of compounds 1a and 1b were also
measured in pyridine and benzonitrile and a summary of redox
potentials is given in Table 2 along with redox potentials for re-
duction and oxidation of the related compounds 6–9. Almost
the same peak or half wave potentials are observed for the
Table 2. Half-wave and peak potentials (V vs. SCE) of investigated com-
pounds in CH2Cl2, PhCN and pyridine containing 0.1m TBAP.
Solvent Cpd
Oxidation
Reduction
2nd
4th 3rd
2nd
1st
1st
3rd
CH2Cl2 1a
1.40 1.32
1.37 1.26
0.92
0.95
0.74[a] À1.20 À1.71
0.74[a] À1.27 À1.73
1b
9
6
7
8
0.96a 0.76[a] À1.34 À1.46
À1.71
À1.80
1.32 1.17
1.02
1.06
1.11
1.16
0.83
À1.26 À1.70
0.85[a] À1.28 À1.65
0.80
0.84
À1.34 À1.75
À1.33 À1.72
(TPP)Zn
carb a
carb b
carb c
1.32[a]
1.28[a]
1.44[a]
PhCN
1a
1b
9
6
1.33
1.32
0.99
0.95
0.98
1.21
0.78[a] À1.30 À1.74
0.77[a] À1.30 À1.73
0.73
0.88
À1.28 À1.63
À1.23 À1.64
À1.88
1.69 1.54
7
1.40[a] 1.13[a] 0.89[a] À1.30 À1.69[a] À1.86
(TPP)Zn
carb a
carb b
1.13
0.83
À1.34 À1.72
1.30[a]
1.28[a]
Py[b]
1a
1b
9
6
1.05
1.05
0.82[a] À1.25 À1.76
0.77[a] À1.25 À1.78
0.84[a] À1.31 À1.86
À2.06[a]
0.95[a] À1.21 À1.81[a] À1.96
0.91[a] À1.21 À1.80[a] À1.93
7
(TPP)Zn
1.09
0.83
À1.39 À1.66
[a] Irreversible peak potential at scan rate=0.1 VsÀ1; [b] carbazole oxida-
tion is not observed in pyridine due to the solvent oxidation potential
window.
Figure 4. Cyclic voltammograms illustration HOMO–LUMO gap of 9, 1b,
(TPP)Zn, 6 and 7 in PhCN containing 0.1m TBAP, scan rate=0.1 VsÀ1
.
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mono- and bisporphyrin derivatives but differences do exist as
illustrated in Figure 4 which shows the first reduction and first
oxidation for 9, 1b, 6, 7 and (TPP)Zn in PhCN containing 0.1m
TBAP.
uct with a Soret band at 454–460 nm and an intense Q band
at 651–655 nm.
As shown in Figure 7, the neutral compound 1b in CH2Cl2
has bands at 446, 570 and 624 nm, while the species generat-
ed after the first reduction at a controlled potential of À1.45 V
has bands at 456, 596 and 652 nm. When the applied potential
is set at À1.95 V, the newly formed bands at 456 and 652 nm
decrease in intensity and the final spectrum is characterized by
a Soret-like band at 484 nm and a broad Q band at 771 nm.
Similar spectral changes are seen for the two reductions of
1b in pyridine. The neutral compound has major absorbance
at 453, 578 and 642 nm and these peaks are red-shifted to 457
and 657 nm after reduction (Figure 7b). Upon further reduc-
tion in pyridine, the Soret and Q band both decrease in inten-
sity as a broad band between 700 to 900 nm is formed.
Finally, it should be noted that compound 1a also displays
similar types of shifts in the UV/Vis spectrum upon reduction
and the final product upon reduction in PhCN is characterized
by bands at 453 and 655 nm.
As seen in Figure 4 and Table 2, the easiest oxidation occurs
in PhCN for the linked bisporphyrins 1a, 1b and 9 and the
hardest for the monoporphyrins 6 and 7. The HOMO–LUMO
gap ranges from 2.01 to 2.19 V, with the smallest values being
observed for the linked bisporphyrins 1a, 1b and 9 (Figure 4
and Table 2), consistent with the larger conjugated p system of
these species.
As indicated above, the initial site of electron transfer is the
conjugated macrocycle for all of the examined porphyrins,
both upon oxidation and reduction, but this is not reflected in
the UV–visible spectrum of the electroreduced compounds 9,
1a and 1b. Examples of the spectral changes during reduction
of 6, 1b and 9 in PhCN at a controlled potential of À1.50 V are
illustrated in Figure 5 and suggest a reduction product of 1b
and 9 having substantial electron density on the linking group.
This is not the case for 6 where the significant loss of intensity
for all bands clearly indicates reduction at the conjugated p sy-
stem of the macrocycle.
The cyclic voltammetric data suggest that the first two elec-
tron abstractions are from the porphyrin macrocycle and this
Similar types of UV–visible spectral changes are observed
during the first controlled potential reduction of 9 in PhCN,
CH2Cl2 and pyridine. This is illustrated in Figure 6 where all of
the bands red shift upon electron addition to give a final prod-
Figure 5. UV/Vis spectrum change of 6, 1b and 9 in PhCN upon first reduc-
tion at À1.50 V, 0.1m TBAP.
Figure 6. Thin-layer UV/Vis spectrum change of compound 9 during first re-
duction in: a) PhCN, b) CH2Cl2, and c) Py containing 0.1m TBAP.
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Figure 7. UV/Vis spectral changes of 1b during controlled potential reduction in: a) CH2Cl2, and b) pyridine, 0.1m TBAP.
Summary
conclusion is verified by spectroelectrochemical monitoring of
the controlled potential oxidations in CH2Cl2 and PhCN
(Figure 8). In the first oxidations, the bands at 446 and 624 nm
for the neutral compound 1b both decrease in intensity as
a broad band centered at 804 nm in CH2Cl2 or 812 nm in PhCN
appears, indicating a porphyrin ring-centered electron transfer.
The intensity of the Soret band continues to decrease when
the applied potential is shifted to 1.15 or 1.20 V and the final
UV–visible spectrum is consistent with that of a porphyrin di-
cation.
In conclusion, the synthesis and physicochemical characteriza-
tion of diyne dimer 9, a N-carbazole porphyrin 8 and two Zn-
porphyrin tweezers with a 9-substituted carbazole as a linker
has been described. Both compounds 1a, 1b show strong
linear absorption in the Soret region and moderate fluores-
cence quantum yield, leading to high brightness reaching
30000mÀ1 cmÀ1. Furthermore, these dyads present a two-
photon absorption maximum at 920 nm with two-photon
Figure 8. UV/Vis spectral changes of 1b during controlled potential oxidation in: a) CH2Cl2, and b) PhCN, 0.1m TBAP.
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[5] a) C. P. Gros, S. M. Aly, M. El Ojaimi, J.-M. Barbe, F. Brisach, A. S. Abd-El-
Aziz, P. D. Harvey, J. Porphyrins Phthalocyanines 2007, 11, 244–257;
b) C.-H. Lee, H. Yoon, P. Kim, S. Cho, D. Kim, W.-D. Jang, Chem. Commun.
2011, 47, 4246–4248; c) Y. Liu, H. Lin, J. Li, J. T. Dy, K. Tamaki, J. Nakaza-
ki, D. Nakayama, C. Nishiyama, S. Uchida, T. Kubob, H. Segawa, Phys.
Chem. Chem. Phys. 2012, 14, 16703–16712; d) A. Nowak-Król, M. Grzy-
bowski, J. Romiszewski, M. Drobizhev, G. Wicks, M. Chotkowski, A.
Rebane, E. Gorecka, D. T. Gryko, Chem. Commun. 2013, 49, 8368–8370;
e) A. Ryan, A. Gehrold, R. Perusitti, M. Pintea, M. Fazekas, O. B. Locos, F.
Blaikie, M. O. Senge, Eur. J. Org. Chem. 2011, 5817–5844; f) O. Varnavski,
J. E. Raymond, Z. Seok Yoon, T. Yotsutuji, K. Ogawa, Y. Kobuke, T. Good-
son, J. Phys. Chem. C 2014, 118, 28474–28481.
[6] R. D. Hartnell, A. J. Edwards, D. P. Arnold, J. Porphyrins Phthalocyanines
2002, 6, 695–707.
[7] C. Glaser, Ber. Dtsch. Chem. Ges. 1869, 2, 422–424.
[8] K. Sonogashira, Y. Tohda, N. Hagihara, Tetrahedron Lett. 1975, 16, 4467–
4470.
[9] B. Habermeyer, A. Takai, C. P. Gros, M. El Ojaimi, J.-M. Barbe, S. Fukuzu-
mi, Chem. Eur. J. 2011, 17, 10670–10681.
absorption cross-section in the 1200 GM range. Further work
is under investigation to study the effect of the linker (e.g.,
heterofluorene vs. carbazole) between the two porphyrin units.
Acknowledgements
The Centre National de la Recherche Scientifique (ICMUB, UMR
CNRS 6302) is gratefully thanked for financial support. Support
was also provided by the Robert A. Welch Foundation (KMK,
grant E-680) and by the CNRS, the UniversitØ de Bourgogne
and the Conseil RØgional de Bourgogne through the 3MIM in-
tegrated project (Marquage de MolØcules par les MØtaux pour
l’Imagerie MØdicale). Y.C. thanks the Conseil RØgional de Bour-
gogne for a postdoctoral grant. We are thankful to Dr. Philippe
Richard for molecular modeling of 9. Dr. Fanny Picquet and
Mrs. Marie JosØ Penouilh are warmly acknowledged for techni-
cal support. The authors are very thankful to Dr. Benoit Haber-
meyer and Porphychem Company for providing some porphy-
rin precursors.
[10] N. Miyaura, A. Suzuki, J. Organomet. Chem. 1981, 204-223, 769.
[11] A. S. Hinman, B. J. Pavelich, A. E. Kondo, S. Pons, J. Electroanal. Chem. In-
terfacial Electrochem. 1987, 234, 145–162.
[12] M. Drobizhev, A. Karotki, M. Kruk, N. Zh. Mamardashvili, A. Rebane,
Chem. Phys. Lett. 2002, 361, 504–512.
[13] a) Y. Fang, K. M. Kadish, P. Chen, Y. Gorbunova, Y. Enakieva, A. Tsivadze,
A. Bessmertnykh-Lemeune, R. Guilard, J. Porphyrins Phthalocyanines
2013, 17, 1035–1045; b) P. Chen, H. Lau, B. Habermeyer, C. P. Gros, J.-M.
Barbe, K. M. Kadish, J. Porphyrins Phthalocyanines 2011, 15, 467–479;
c) Z. Ou, J. Shao, H. Zhao, K. Ohkubo, I. H. Wasbotten, S. Fukuzumi, A.
Ghosh, K. M. Kadish, J. Porphyrins Phthalocyanines 2004, 8, 1236–1247;
d) J.-M. Barbe, B. Habermeyer, T. Khoury, C. P. Gros, P. Richard, P. Chen,
K. M. Kadish, Inorg. Chem. 2010, 49, 8929–8940; e) R. Guilard, F. JØrome,
J.-M. Barbe, C. P. Gros, Z. Ou, J. Shao, J. Fischer, R. Weiss, K. M. Kadish,
Inorg. Chem. 2001, 40, 4856–4865; f) R. Guilard, C. P. Gros, J.-M. Barbe,
E. Espinosa, F. JØrome, A. Tabard, J.-M. Latour, J. Shao, Z. Ou, K. M.
Kadish, Inorg. Chem. 2004, 43, 7441–7455; g) K. M. Kadish, Z. Ou, J.
Shao, C. P. Gros, J.-M. Barbe, F. JØrome, F. Bolze, F. Burdet, R. Guilard,
Inorg. Chem. 2002, 41, 3990–4005.
Keywords: carbazoles · electrochemistry · Glaser coupling ·
Sonogashira coupling · synthetic methods
[1] A. Ryan, B. Tuffy, S. Horn, W. J. Blau, M. O. Senge, Tetrahedron 2011, 67,
8248–8254.
[2] L.-L. Li, E. W. G. Diau, Chem. Soc. Rev. 2013, 42, 291–304.
[3] a) K. Ogawa, Applied Sci. 2014, 4, 1–18; b) M. Pawlicki, H. A. Collins,
R. G. Denning, H. L. Anderson, Angew. Chem. Int. Ed. 2009, 48, 3244–
3266; Angew. Chem. 2009, 121, 3292–3316.
[4] a) E. Dahlstedt, H. A. Collins, M. Balaz, M. K. Kuimova, M. Khurana, B. C.
Wilson, D. Phillips, H. L. Anderson, Org. Biomol. Chem. 2009, 7, 897–
904; b) M. K. Kuimova, H. A. Collins, M. Balaz, E. Dahlstedt, J. A. Levitt, N.
Sergent, K. Suhling, M. Drobizhev, N. S. Makarov, A. Rebane, H. L. Ander-
son, D. Phillips, Org. Biomol. Chem. 2009, 7, 889–896.
Received: April 25, 2015
Published online on July 14, 2015
Chem. Eur. J. 2015, 21, 12018 – 12025
www.chemeurj.org
12025
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