Fusing Porphyrins and Phospholes: Synthesis and Analysis of a Phosphorus-Containing Porphyrin

Article abstract of DOI:10.1002/anie.201607417

A phosphole-fused porphyrin dimer, as a representative of a new class of porphyrins with a phosphorus atom, was synthesized for the first time. The porphyrin dimer exhibits remarkably broadened absorption, indicating effective π-conjugation over the two porphyrins through the phosphole moiety. The porphyrin dimer possesses excellent electron-accepting character, which is comparable to that of a representative electron-accepting material, [60]PCBM. These results provide access to a new class of phosphorus-containing porphyrins with unique optoelectronic properties.

Full text of DOI:10.1002/anie.201607417

Angewandte
Communications
Chemie
International Edition: DOI: 10.1002/anie.201607417
German Edition: DOI: 10.1002/ange.201607417
Porphyrinoids
Hot Paper
Fusing Porphyrins and Phospholes: Synthesis and Analysis of a Phos-
phorus-Containing Porphyrin
Tomohiro Higashino,* Tomoki Yamada, Tsuneaki Sakurai, Shu Seki, and Hiroshi Imahori*
Abstract: A phosphole-fused porphyrin dimer, as a represen-
tative of a new class of porphyrins with a phosphorus atom,
was synthesized for the first time. The porphyrin dimer exhibits
remarkably broadened absorption, indicating effective p-
conjugation over the two porphyrins through the phosphole
moiety. The porphyrin dimer possesses excellent electron-
accepting character, which is comparable to that of a represen-
tative electron-accepting material, [60]PCBM. These results
provide access to a new class of phosphorus-containing
porphyrins with unique optoelectronic properties.
P
orphyrins are macrocyclic 18p-conjugated molecules that
Figure 1. Examples of porphyrins with phosphorus atoms.
have been actively studied in various fields owing to their
potential for diverse applications, for example, in materials
science and as catalysts, as well as owing to their vital roles in
natural systems.[1] As their attractive properties are attributed
to the 18p electron conjugated system, their structural and
electronic properties can be tuned by metalation, peripheral
modification, and replacement of a pyrrole ring with another
heterocycle.[2,3] In particular, the chemistry of porphyrins with
phosphorus atoms has been actively investigated in the light
of the ability of the phosphorus atom to form coordination
and covalent bonds (Figure 1). For instance, phosphorus-
containing porphyrin complexes can be used as a structural
motif to create oligomeric architectures. The wheel-and-axle
phosphorus(V) porphyrin arrays 1 were synthesized by
Shimidzu and co-workers.[4] Furthermore, phosphorus inser-
tion has recently been shown to be an effective approach for
Phosphaporphyrins 4 have been presented by Matano and
co-workers as core-modified porphyrins containing a phosp-
hole ring.[7] They corroborated that replacement of a pyrrole
ring with a phosphole has an impact on the structure,
aromaticity, and optical and electrochemical properties as
well as on the coordination abilities. However, to the best of
our knowledge, no porphyrins with a peripherally fused
phosphole structure such as 5 have been reported in spite of
extensive efforts to explore various phosphole-fused p-con-
jugated molecules.[8] We envisioned that such phosphole-
fused porphyrins would exhibit unique optical and electro-
chemical properties owing to the phosphole moiety. Towards
this goal, we exploited a new synthetic method to create
bis(pyrrolo)heteroles.[9] On the basis of the reactivity of
bis(pyrrolo)phosphole as a key building block, we expected
that the two porphyrin rings would be integrated through
condensation with the bis(pyrrolo)phosphole. Herein, we
report for the first time the synthesis of phosphole-fused
porphyrin dimers as a new class of porphyrins with a phos-
phorus atom.
creating new porphyrinoids.[5] Latos-Graz˙ynski and co-work-
´
ers reported the phosphorus complex of N-fused porphyrin 2,
a 20p porphyrin, as an isophlorin analogue.[5a] As another
example, peripherally phosphanylated porphyrins have also
been synthesized, which can form peripherally metalated
porphyrins.[6] The PCP pincer complexes of bis(phosphanyl)-
porphyrin 3 were catalytically active depending on the central
metal atom in the porphyrin core.[6c]
The phosphole-fused porphyrin dimer 12 was synthesized
by the route shown in Scheme 1. The treatment of 4,4’-
dibromo-3,3’-bipyrrole 6[9] with t-BuLi and PhPCl2 followed
by addition of elemental sulfur afforded the triisopropylsilyl-
protected bis(pyrrolo)phosphole 7 in 58% yield. Whereas the
[*] Dr. T. Higashino, T. Yamada, Dr. T. Sakurai, Prof. Dr. S. Seki,
Prof. Dr. H. Imahori
PIII derivative is unstable under ambient atmosphere,[9] the P
=
Department of Molecular Engineering
Graduate School of Engineering, Kyoto University
Nishikyo-ku, Kyoto, 615-8510 (Japan)
E-mail: t-higa@scl.kyoto-u.ac.jp
S compound 7 is sufficiently stable to be used as the precursor.
Then, 7 was deprotected with tetrabutylammonium fluoride
(TBAF) to give bis(pyrrolo)phosphole 8. The reaction of 5,10-
di(4-methylphenyl)tripyrrane 9 with Vilsmeier reagent pro-
vided diformyltripyrrane 10 in 52% yield. Tripyrrane dicar-
binol 11 was obtained by the reduction of 10 with NaBH4.
Then, we attempted the acid-catalyzed condensation of 8 and
11. However, we detected only a trace amount of 12 under
standard reaction conditions for porphyrin synthesis. After
extensive screening, we finally succeeded in isolating the
imahori@scl.kyoto-u.ac.jp
Prof. Dr. H. Imahori
Institute for Integrated Cell Material Sciences (WPI-iCeMS)
Kyoto University, Nishikyo-ku, Kyoto, 615-8510 (Japan)
Supporting information and the ORCID identification number(s) for
the author(s) of this article can be found under:
http://dx.doi.org/10.1002/anie.201607417.
Angew. Chem. Int. Ed. 2016, 55, 1 – 6
ꢀ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
1
These are not the final page numbers!

Angewandte
Communications
Chemie
of 12 revealed two almost co-planar porphyrin macrocycles,
which suggests effective p-conjugation over the two porphy-
rin moieties (Figure 3). Whereas porphyrin ring B adopts
Scheme 1. Synthesis of phosphole-fused porphyrin dimer 12.
DCE=1,2-dichloroethane, MSA=methanesulfonic acid, TBAF=tetra-
butylammonium fluoride, TIPS=triisopropylsilyl.
desired porphyrin dimer 12 in 0.7% yield upon condensation
of 8 and 11 with 0.4 equiv of methanesulfonic acid (MSA) at
608C in 1,2-dichloroethane for 1 h followed by oxidation with
6 equiv of 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ) at
room temperature for 3 h. While the yield was low, we
performed the synthesis repeatedly and obtained a sufficient
amount of 12 for all measurements (ca. 10 mg). The high-
resolution electrospray ionization time-of-flight (HR-ESI-
TOF) mass spectrum of 12 exhibited a positive ion peak at m/
z 1117.3936 (calcd for C74H54N8PS: 1117.3924 [M+H]+),
which is consistent with the molecular structure of 12. The
1H NMR spectrum of 12 in CD2Cl2 is shown in Figure 2. The
Figure 3. X-ray crystal structure of 12: a) top view and b) side view.
Thermal ellipsoids set at 50% probability. Solvent molecules and
meso-aryl substituents omitted for clarity.
a highly planar conformation, a slight distortion was observed
for porphyrin ring A. The mean-plane deviations (MPDs) of
the porphyrin macrocycles A and B (24 core atoms) were
calculated to be 0.234 and 0.035 ꢀ, respectively. In the
packing structure, 12 forms a face-to-face dimeric structure, in
which the intermolecular distance is approximately 3.5 ꢀ
(Figure S5). Notably, this dimeric structure forms a slipped p–
p-stacked structure (Figure S6). The distance between the
two porphyrin substructures is also about 3.5 ꢀ. This p–p
interaction probably induces the distortion of porphyrin
ring A in the packing structure. The dimeric structure and
effective p–p interactions would be favorable for potential
applications of 12 as a charge-transport material (see
below).[11]
The UV/Vis absorption spectra of 12 and 5,10-di(4-
methylphenyl)porphyrin 13 in CH2Cl2 are shown in
Figure 4. In contrast to porphyrin monomer 13, porphyrin
dimer 12 displays remarkably broadened absorption whereas
the absorption coefficients of 12 at l ꢀ 400 nm are smaller
than those of 13. The split Soret bands are broadened in the
range of l = 400–500 nm. The lowest-energy Q band of 12
(l = 668 nm) is red-shifted by Dl = 43 nm relative to that of 13
(l = 625 nm),[12] and the absorption edge reaches to 700 nm. It
is noteworthy that this red shift of the Q band for 12 is
significantly larger than that for a usual b–b-linked porphyrin
dimer (Dl = 8 nm).[13] Thus these absorption features support
an effective interaction between the two porphyrin macro-
cycles through the phosphole moiety. The steady-state
fluorescence spectrum of 12 was recorded in CH2Cl2, and an
emission peak was detected at l = 683 nm (Figure 4). The
Stokes shift of 12 (330 cmÀ1) is rather comparable to that of 13
Figure 2. 1H NMR spectrum (aromatic region) of porphyrin dimer 12
in CD2Cl2 at 258C.
six resonances arising from the b-protons are observed in the
range of d = 8.90–10.03 ppm, and the two resonances arising
from the meso protons are observed at d = 10.51 and
12.07 ppm. It should be noted that the resonance of the
meso-Ha protons is remarkably downfield-shifted because of
the aromatic ring current of the neighboring porphyrin
macrocycle. The 31P NMR spectrum displays a resonance
=
from the P S moiety at d = 18.76 ppm (see the Supporting
Information, Figure S4).
To our delight, single crystals suitable for X-ray diffraction
analysis were obtained by vapor diffusion of 2-propanol into
a solution of 12 in 1,2-dichloroethane.[10] The crystal structure
2
www.angewandte.org
ꢀ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Angew. Chem. Int. Ed. 2016, 55, 1 – 6
These are not the final page numbers!

Angewandte
Communications
Chemie
electron-accepting ability, combined with effective p–p stack-
ing in the crystal structure, suggests that 12 has potential as an
n-type semiconductor.
To gain further insight into the electronic properties of 12,
we performed DFT calculations at the B3LYP/6-31G(d,p)
level of theory. First, we found that 12a is the most stable NH
tautomer of 12 (Figure 5a). However, the difference in the
Figure 4. UV/Vis absorption (solid lines) and emission (dashed lines)
spectra of 12 (black) and 13 (gray) in CH2Cl2. The samples were
excited at l=400 nm.
(230 cmÀ1), which is consistent with the highly rigid planar
structure of 12.
Figure 5. a) Three NH tautomers of 12 and their relative energies.
b) Selected Kohn–Sham orbitals of 12a at the B3LYP/6-31G(d,p) level
of theory.
The electrochemical properties of 7, 12, and 13 were
studied by cyclic voltammetry (CV) and differential pulse
voltammetry (DPV) in CH2Cl2 vs. ferrocene/ferrocenium
cation (Fc/Fc+) with tetrabutylammonium hexafluorophos-
phate (Bu4NPF6) as the electrolyte (Figure S7). Bis-
(pyrrolo)phosphole 7 gave rise to an oxidation peak at
0.73 V whereas no reduction peak was visible at potentials up
to À2.5 V. The electrochemical properties of 7 are similar to
those of other bis(pyrrolo)heteroles.[9] Porphyrin monomer 13
displays two reversible reduction peaks at À1.65 and À2.05 V
and two quasi-reversible oxidation peaks at 0.50 and 0.91 V.
On the other hand, 12 underwent three quasi-reversible
reductions at À1.19, À1.44, and À1.90 V and two irreversible
oxidations at 0.53 and 0.75 V. The first and second oxidation
potentials of 12 stem mainly from the two porphyrin moieties
and the phosphole conjugated to the porphyrins, respectively
(see below). The effective p-expansion over the two porphyr-
ins lowers the oxidation potentials while they are shifted in
the positive direction by the electron-withdrawing effect of
the phosphorus(V) center, offsetting the effects; therefore,
the oxidation potentials of 12 are comparable to those of 13
and 7. In contrast, the three reduction peaks, including the
unexpected new one, are significantly shifted in the positive
direction, probably owing to the strongly electron-accepting
character arising from the phosphole moiety (see below). The
three one-electron reduction processes of 12 reflect distinct
electronic communication over the two porphyrin moieties
relative energies of the tautomers 12a–12c is quite small (ca.
3 kJmolÀ1), which agrees with the single NH peak in the
1H NMR spectrum of 12 at room temperature (Figure S4).
The Kohn–Sham frontier orbitals of 12a are illustrated in
Figures 5b and S8. For the eight Kohn–Sham orbitals
composed of four porphyrin orbitals, the orbital distributions
are well delocalized over the whole p-conjugated system.
HOMO and HOMO-1 of 12a originate from the HOMO of
13. As the phosphole ring is located on the node of HOMO/
HOMO-1, these orbitals mainly exhibit porphyrin character.
However, the energy levels of HOMO and HOMO-1 of 12a
are slightly shifted in the negative direction owing to the
electron-withdrawing effect of the phosphorus(V) atom. On
the other hand, the LUMO of 12a is well delocalized over the
two porphyrin moieties as well as the phosphole ring (Fig-
ure 5b). Importantly, the LUMO of 12a is derived from the
LUMO + 1 of 13 and remarkably stabilized compared to the
LUMO + 1/LUMO + 2, which stem from the LUMO of 13
(Figure S8). The new reduction peak observed in the cyclic
voltammogram was rationalized by the stabilized LUMO
(Figure S7). As the LUMO displays a large orbital distribu-
tion on the phosphole ring, the LUMO possesses phosphole
character to a large extent.[8,14] This is a consequence of the
stabilization solely by the fusion of the two porphyrins and the
phosphole ring.
through the phosphole moiety. The large difference (DEred
=
0.25 V) between the first and second reduction potentials also
indicates effective electronic communication. It is worth
noting that the first reduction potential of 12 is more positive
than those of phosphole derivatives with high electron
affinity.[14] Given that the energy level of Fc/Fc+ is À4.8 eV
under vacuum, the LUMO level of 12 was estimated to be
À3.61 eV.[15] This value is close to that of [60]PCBM (ca.
À3.7 eV),[16] a representative fullerene derivative that is used
as an electron-accepting material for charge transport as well
as an organic photovoltaic material.[17] Therefore, this high
We also calculated nucleus-independent chemical shift
(NICS) values for the optimized structure of 12a (Figure S9).
The NICS value at the center of the porphyrin moiety is
À13.8 ppm, whereas the NICS value at the center of the
phosphole ring is + 8.33 ppm. This large positive NICS value
results from the double diatropic ring current effect of the two
porphyrin macrocycles. Although the phosphole ring can
participate in p-conjugation with the two porphyrin moieties,
it has little impact on the 18p aromatic character of the
porphyrin moiety. Furthermore, we carried out time-depen-
Angew. Chem. Int. Ed. 2016, 55, 1 – 6
ꢀ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.angewandte.org
3
These are not the final page numbers!

Angewandte
Communications
Chemie
dent DFT (TD-DFT) calculations to evaluate the absorption
(Figure S10 and Table S2). The oscillator strengths of the
HOMO/LUMO and HOMO-1/LUMO transitions are small
(f < 0.03) whereas the HOMO-2/LUMO transition has a large
oscillator strength (f = 0.41). These results suggest that the
absorption at l = 600–700 nm is not caused by intramolecular
charge transfer (ICT) from the porphyrin core to the phosp-
hole ring, but mainly by p–p* transitions of the porphyrin
dimer with phosphole moiety.
Finally, we assessed the charge-transport ability of 12 and
13 by flash photolysis time resolved microwave conductivity
(FP-TRMC) measurements.[18] The FP-TRMC profiles for
drop-cast films of 12 and 13, prepared from toluene solution,
upon irradiation at l = 355 nm are displayed in Figure S11,
with a charge recombination rate constant high enough
compared to the time constant of the measurement system
(ca. 100 ns), especially for 12. The maximum transient
conductivity (fSm)max for 13 was determined to be 6.5 ꢁ
10À6 cm2 VÀ1 sÀ1, where f and Sm are the charge carrier
generation efficiency and the sum of the charge carrier
mobilities. Importantly, the (fSm)max value for 12 (5.5 ꢁ
10À5 cm2 VÀ1 sÀ1) is one order of magnitude larger than that
for 13. This remarkable difference is most likely due to the
effective p–p interaction in the solid state, supporting the
potential utility of the phosphole-fused structure as a charge-
transport material.
In summary, we have reported the synthesis of phosphole-
fused porphyrin dimer 12 as a representative of a new class of
phosphorus-containing porphyrins, exemplifying the poten-
tial utility of our bis(pyrrolo)heteroles as building blocks for
heterole-fused porphyrin dimers. Porphyrin dimer 12 exhibits
effective p-conjugation over the two porphyrin macrocycles
through the phosphole moiety. The low reduction potential of
12 is solely due to the integration of the two porphyrin
moieties into one large p-system through the phosphole
moiety. FP-TRMC measurements suggest the prospective use
of 12 as a novel charge-transport material. The optical and
electrochemical properties of the phosphole-fused porphyrin
dimer could be tuned by further modifications of the
phosphorus atom, metalation of the porphyrin core, or
peripheral functionalizations. Furthermore, we believe that
this report will enable the synthesis of new classes of
porphyrins containing not only phosphorus but also other
main-group elements, such as sulfur and silicon.
[1] a) The Porphyrin Handbook, Vol. 1 – 10 (Eds.: K. M. Kadish,
K. M. Smith, R. Guilard), Academic Press, San Diego, 2000;
b) D. Gust, T. A. Moore, A. L. Moore, Acc. Chem. Res. 2001, 34,
40 – 48; c) D. Holten, D. F. Bocian, J. S. Lindsey, Acc. Chem. Res.
2002, 35, 57 – 69; d) H. Imahori, J. Phys. Chem. B 2004, 108,
6130 – 6143; e) M. Ethirajan, Y. Chen, P. Joshi, R. K. Pandey,
Chem. Soc. Rev. 2011, 40, 340 – 362; f) T. Tanaka, A. Osuka,
Chem. Soc. Rev. 2015, 44, 943 – 969; g) T. Higashino, H. Imahori,
Dalton Trans. 2015, 44, 448 – 463.
[2] a) B. M. J. M. Suijkerbuijk, R. J. M. Klein Gebbink, Angew.
Chem. Int. Ed. 2008, 47, 7396 – 7421; Angew. Chem. 2008, 120,
7506 – 7532; b) M. O. Senge, Chem. Commun. 2011, 47, 1943 –
1960; c) H. Yorimitsu, A. Osuka, Asian J. Org. Chem. 2013, 2,
356 – 373.
´
[3] a) P. J. Chmielewski, L. Latos-Graz˙ynski, Coord. Chem. Rev.
2005, 249, 2510 – 2533; b) I. Gupta, M. Ravikanth, Coord. Chem.
Rev. 2006, 250, 468 – 518.
[4] a) H. Segawa, K. Kunimoto, K. Susumu, M. Taniguchi, T.
Shimidzu, J. Am. Chem. Soc. 1994, 116, 11193 – 11194; b) K.
Susumu, K. Kunimoto, H. Segawa, T. Shimidzu, J. Phys. Chem.
1995, 99, 29 – 34.
´
[5] a) A. Młodzianowska, L. Latos-Graz˙ynski, L. Szterenberg,
Inorg. Chem. 2008, 47, 6364 – 6374; b) E. Pacholska-Dudziak,
´
F. Ulatowski, Z. Ciunik, L. Latos-Graz˙ynski, Chem. Eur. J. 2009,
15, 10924 – 10929.
[6] a) Y. Matano, K. Matsumoto, Y. Nakao, H. Uno, S. Sakaki, H.
Imahori, J. Am. Chem. Soc. 2008, 130, 4588 – 4589; b) Y. Matano,
K. Matsumoto, H. Hayashi, Y. Nakao, T. Kumpulainen, V.
Chukharev, N. V. Tkachenko, H. Lemmetyinen, S. Shimizu, N.
Kobayashi, D. Sakamaki, A. Ito, K. Tanaka, H. Imahori, J. Am.
Chem. Soc. 2012, 134, 1825 – 1839; c) K. Fujimoto, T. Yoneda, H.
Yorimitsu, A. Osuka, Angew. Chem. Int. Ed. 2014, 53, 1127 –
1130; Angew. Chem. 2014, 126, 1145 – 1148.
[7] a) Y. Matano, H. Imahori, Acc. Chem. Res. 2009, 42, 1193 – 1204;
b) Y. Matano, T. Nakabuchi, T. Miyajima, H. Imahori, H.
Nakano, Org. Lett. 2006, 8, 5713 – 5716; c) Y. Matano, T.
Nakabuchi, S. Fujishige, H. Nakano, H. Imahori, J. Am. Chem.
Soc. 2008, 130, 16446 – 16447; d) Y. Matano, M. Nakashima, T.
Nakabuchi, H. Imahori, S. Fujishige, H. Nakano, Org. Lett. 2008,
10, 553 – 556; e) T. Nakabuchi, Y. Matano, H. Imahori, Org. Lett.
2010, 12, 1112 – 1115; f) Y. Matano, T. Nakabuchi, H. Imahori,
Pure Appl. Chem. 2010, 82, 583 – 593; g) T. Nakabuchi, M.
Nakashima, S. Fujishige, H. Nakano, Y. Matano, H. Imahori, J.
Org. Chem. 2010, 75, 375 – 389.
[8] a) A. Fukazawa, S. Yamaguchi, Chem. Asian J. 2009, 4, 1386 –
1400; b) Y. Matano, H. Imahori, Org. Biomol. Chem. 2009, 7,
1258 – 1271; c) Y. Ren, T. Baumgartner, Dalton Trans. 2012, 41,
7792 – 7800; d) T. Baumgartner, Acc. Chem. Res. 2014, 47, 1613 –
1622; e) M. Stolar, T. Baumgartner, Chem. Asian J. 2014, 9,
1212 – 1225.
[9] T. Higashino, H. Imahori, Chem. Eur. J. 2015, 21, 13375 – 13381.
[10] Crystallographic data for 12: C74H53N8PS·C3H8O·0.5(C2H4Cl2),
Mr = 1226.84, monoclinic, C2/c (No.15), a = 23.139(10), b =
18.670(8), c = 30.139(12) ꢀ, b = 90.068(11)8, V= 13020(9) ꢀ3,
Acknowledgements
This work was supported by the JSPS (KAKENHI Grant
Numbers 15K17822 (T.H.) and 25220801 (H.I.)). We thank
Dr. Takayuki Tanaka and Prof. Atsuhiro Osuka (Kyoto
University) for assistance with X-ray crystal structure anal-
ysis.
1calcd = 1.252 gcmÀ3
, Z = 8, R1 = 0.0836 [I > 2s(I)], wR2 =
0.3069 (all data), GOF = 1.067. CCDC 1495318 contains the
supplementary crystallographic data for this paper. These data
can be obtained free of charge from The Cambridge
Crystallographic Data Centre.
[11] a) A. Wakamiya, H. Nishimura, T. Fukushima, F. Suzuki, A.
Saeki, S. Seki, I. Osaka, T. Sasamori, M. Murata, Y. Murata, H.
Kaji, Angew. Chem. Int. Ed. 2014, 53, 5800 – 5804; Angew. Chem.
2014, 126, 5910 – 5914; b) W. Nakanishi, N. Matsuyama, D. Hara,
A. Saeki, S. Hitosugi, S. Seki, H. Isobe, Chem. Asian J. 2014, 9,
1782 – 1785.
Keywords: main-group elements · phospholes · phosphorus ·
porphyrin dimers · porphyrinoids
4
www.angewandte.org
ꢀ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Angew. Chem. Int. Ed. 2016, 55, 1 – 6
These are not the final page numbers!

Angewandte
Communications
Chemie
[12] C. Ryppa, M. O. Senge, S. S. Hatscher, E. Kleinpeter, P. Wacker,
Rꢃau, L. Nyulꢂszi, M. Hissler, Chem. Eur. J. 2015, 21, 6547 –
6556.
[15] J. Pommerehne, H. Vestweber, W. Guss, R. F. Mahrt, H. Bꢅssler,
M. Porsch, J. Daub, Adv. Mater. 1995, 7, 551 – 554.
[16] a) J. C. Hummelen, B. W. Knight, F. LePeq, F. Wudl, J. Yao, C. L.
Wilkins, J. Org. Chem. 1995, 60, 532 – 538; b) R. Tao, T.
Umeyama, T. Higashino, T. Koganezawa, H. Imahori, Chem.
Commun. 2015, 51, 8233 – 8236.
U. Schilde, A. Wiehe, Chem. Eur. J. 2005, 11, 3427 – 3442.
[13] a) 5,10,15,20-Tetra(4-tolyl)porphyrin (lQ = 647 nm in CH2Cl2):
S. Zakavi, S. Hoseini, RSC Adv. 2015, 5, 106774 – 106786; b) b-b’-
bis[5,10,15,20-tetra(4-tolyl)porphyrin] (lQ = 655 nm in CH2Cl2):
G. Bringmann, D. C. G. Gçtz, T. A. M. Gulder, T. H. Gehrke, T.
Bruhn, T. Kupfer, K. Radacki, H. Braunschweig, A. Heckmann,
C. Lambert, J. Am. Chem. Soc. 2008, 130, 17812 – 17825.
[17] a) Y. Liu, J. Zhao, Z. Li, C. Mu, W. Ma, H. Hu, K. Jiang, H. Lin,
H. Ade, H. Yan, Nat. Commun. 2014, 5, 5293; b) J. E. Anthony,
A. Facchetti, M. Heeney, S. R. Marder, X. Zhan, Adv. Mater.
2010, 22, 3876 – 3892; c) J. L. Delgado, P.-A. Bouit, S. Filippone,
M. Herranz, N. Martꢄn, Chem. Commun. 2010, 46, 4853 – 4865;
d) G. Li, R. Zhu, Y. Yang, Nat. Photonics 2012, 6, 153 – 161.
[18] a) A. Saeki, Y. Koizumi, T. Aida, S. Seki, Acc. Chem. Res. 2012,
45, 1193 – 1202; b) A. Saeki, S. Seki, T. Takenobu, Y. Iwasa, S.
Tagawa, Adv. Mater. 2008, 20, 920 – 923; c) H. Hayashi, W.
Nihashi, T. Umeyama, Y. Matano, S. Seki, Y. Shimizu, H.
Imahori, J. Am. Chem. Soc. 2011, 133, 10736 – 10739; d) Y.
Matano, H. Ohkubo, Y. Honsho, A. Saito, S. Seki, H. Imahori,
Org. Lett. 2013, 15, 932 – 935.
[14] a) Y. Matano, T. Miyajima, T. Fukushima, H. Kaji, Y. Kimura, H.
Imahori, Chem. Eur. J. 2008, 14, 8102 – 8115; b) A. Saito, T.
Miyajima, M. Nakashima, T. Fukushima, H. Kaji, Y. Matano, H.
Imahori, Chem. Eur. J. 2009, 15, 10000 – 10004; c) Y. Matano, A.
Saito, T. Fukushima, Y. Tokudome, F. Suzuki, D. Sakamaki, H.
Kaji, A. Ito, K. Tanaka, H. Imahori, Angew. Chem. Int. Ed. 2011,
50, 8016 – 8020; Angew. Chem. 2011, 123, 8166 – 8170; d) Y.
Dienes, M. Eggenstein, T. Kꢂrpꢂti, T. C. Sutherland, L. Nyulꢂszi,
T. Baumgartner, Chem. Eur. J. 2008, 14, 9878 – 9889; e) Y. Ren,
Y. Dienes, S. Hettel, M. Parvez, B. Hoge, T. Baumgartner,
Organometallics 2009, 28, 734 – 740; f) H. Tsuji, K. Sato, Y. Sato,
E. Nakamura, J. Mater. Chem. 2009, 19, 3364 – 3366; g) H. Tsuji,
K. Sato, Y. Sato, E. Nakamura, Chem. Asian J. 2010, 5, 1294 –
˝
1297; h) P.-A. Bouit, A. Escande, R. Szucs, D. Szieberth, C.
Lescop, L. Nyulꢂszi, M. Hissler, R. Rꢃau, J. Am. Chem. Soc.
Received: August 1, 2016
˝
2012, 134, 6524 – 6527; i) F. Riobꢃ, R. Szucs, P.-A. Bouit, D.
Revised: August 20, 2016
Tondelier, B. Geffroy, F. Aparicio, J. Buendꢄa, L. Sꢂnchez, R.
Published online: && &&, &&&&
Angew. Chem. Int. Ed. 2016, 55, 1 – 6
ꢀ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.angewandte.org
5
These are not the final page numbers!

Angewandte
Communications
Chemie
Communications
Porphyrinoids
A phosphole-fused porphyrin dimer as
a representative of a new class of phos-
phorus-containing porphyrins was syn-
thesized. This structure exhibits remark-
ably broadened absorption as well as
unique optoelectronic properties and is
a good electron acceptor owing to the
unique phosphole-fused structure.
T. Higashino,* T. Yamada, T. Sakurai,
S. Seki, H. Imahori*
&&&& — &&&&
Fusing Porphyrins and Phospholes:
Synthesis and Analysis of a Phosphorus-
Containing Porphyrin
6
www.angewandte.org
ꢀ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Angew. Chem. Int. Ed. 2016, 55, 1 – 6
These are not the final page numbers!