Synthesis and characterization of porphyrins bearing four redox-active phenylenediamine pendant groups as a dimensionally oriented π-conjugated system

Article abstract of DOI:10.1016/S0040-4020(02)00828-1

Porphyrins bearing phenylenediamine pendant groups were synthesized to afford dimensionally oriented π-conjugated systems. The structural and electronic characteristics depend on the αααα and αβαβ atropisomers. In the fluorescence emission spectra, the emission from the porphyrin moiety was almost completely quenched. Zinc complexation of the αααα isomer with zinc(II) acetate led to the corresponding zinc complex.

Full text of DOI:10.1016/S0040-4020(02)00828-1

Tetrahedron 58 (2002) 7491–7501
Synthesis and characterization of porphyrins bearing four
redox-active phenylenediamine pendant groups as a
dimensionally oriented p-conjugated system
*
Kaori Saito and Toshikazu Hirao
Department of Applied Chemistry, Faculty of Engineering, Osaka University, Yamada-Oka, Suita, Osaka 565-0871, Japan
Received 15 May 2002; accepted 8 July 2002
Abstract—Porphyrins bearing phenylenediamine pendant groups were synthesized to afford dimensionally oriented p-conjugated systems.
The structural and electronic characteristics depend on the aaaa and abab atropisomers. In the fluorescence emission spectra, the emission
from the porphyrin moiety was almost completely quenched. Zinc complexation of the aaaa isomer with zinc(II) acetate led to the
corresponding zinc complex. q 2002 Elsevier Science Ltd. All rights reserved.
1. Introduction
jugated pendant groups under the controlled orientation.
Such an alignment is considered to permit electronic
communication among the p-conjugated pendant groups
or between the pendant group and porphyrin ring although
the expanded p-conjugation is disrupted. In this context,
porphyrins bearing redox-active phenylenediamine pendant
groups were designed in a previous study.7 We herein
describe the full scope of these porphyrins and the zinc
complexes.
Architecturally ordered orientation of p-conjugated mol-
ecular chains is expected to construct novel p-electronic
systems, but only few reports have appeared on the
alignment of p-conjugated polymer or telomer chains.1
Dimensional orientation of p-conjugated molecular chains
in one molecule is envisioned to provide such a system. In
this context, the utilization of a porphyrin scaffold is
considered to be a convenient approach to orient the
p-conjugated molecular chains.
A number of porphyrin–chromophore hybrid systems have
been synthesized since porphyrins are photochemically and
redox active. Electronic communication and/or photo-
induced electron and energy transfer between the porphyrin
and chromophore are achieved in these systems.2 Chromo-
phores are introduced along or onto the porphyrin plane to
construct two-dimensionally3 or face-to-face4 arrayed
electronic systems, respectively. The latter interaction has
been reported in strapped porphyrins4a–e and other linked
porphyrins.4f–j p-Conjugated oligomer chains such as
oligothiophene5 and oligophenylene6 have been also
introduced to the porphyrin ring to form two-dimensional
p-electronic systems, in which p-conjugated oligomers are
incorporated along the porphyrin plane. meso-Tetraaryl-
porphyrin, in which four aromatic rings at the meso-position
are perpendicular to the porphyrin plane, can be used for
perpendicular alignment of p-conjugated chains on the
porphyrin plane. Furthermore, atropisomerism of meso-
tetraarylporphyrins has an advantage of aligning p-con-
2. Results and discussion
2.1. Synthesis
The porphyrin scaffold 1 for the above-mentioned p-con-
jugated compounds was prepared by condensation of
pyrrole and 2-(ethoxycarbonylmethoxy)naphthalenecarbal-
dehyde according to Lindsey’s method.8 Porphyrin 1 was
obtained as a mixture of the four atropisomers. These abab,
aabb, aaab and aaaa atropisomers were separated by
silica-gel column chromatography and assigned by
Keywords: p-conjugated pendant group; redox-active system; porphyrin;
zinc porphyrin.
*
Corresponding author. Fax: þ81-6-6879-7415;
e-mail: hirao@chem.eng.osaka-u.ac.jp
0040–4020/02/$ - see front matter q 2002 Elsevier Science Ltd. All rights reserved.
PII: S0040-4020(02)00828-1

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K. Saito, T. Hirao / Tetrahedron 58 (2002) 7491–7501
Scheme 1.
comparison with the polarity and spectral data of the related
compounds.9,10 Hydrolysis of the isolated aaaa (1a) and
abab (1b) isomers led to the corresponding acids 2a and
2b, respectively.9 The porphyrins 4a and 4b were
synthesized by amidation of 2a and 2b with 3, via the
acylimidazolides, in 58 and 56% yields, respectively
(Scheme 1). Four phenylenediamine pendant groups were
introduced into the porphyrin scaffold without atropiso-
merization under the conditions employed here. No
atropisomerized derivative was detected in the reaction
mixture.10 The porphyrins 4a and 4b are soluble in DMSO,
DMF, and THF, but are insoluble in a less polar solvent such
as CHCl3, CH2Cl2, and toluene. The porphyrins 5 bearing
the anilinoanilino pendant groups were prepared similarly.
In the synthesis 0of 5a, use of EDCI·HCl (N-(3-dimethyl-
aminopropyl)-N -ethylcarbodiimide hydrochloride) and
HOBt (1-hydroxybenzotriazole) as condensation agents
improved the yield (68%). In contrast to 4, 5a and 5b are
soluble in CHCl3, CH2Cl2, or ClCH2CH2Cl.
2.2. Spectroscopy
1
The structure of these porphyrins was elucidated by H
NMR, FT-IR, and MS (MALDI-TOF or FAB) spec-
1
trometry. In the H NMR spectrum of 4a in DMSO-d6,
the protons of the phenylenediamine pendant groups,
especially the phenylene protons close to the porphyrin
ring, were observed in a higher field as compared with 8, a
single-pendant unit of 4 (Table 1). The shift is likely to be
explained by a ring-current effect of the porphyrin p-ring
system. Furthermore, the phenylene protons of the strands
of 4b shifted to a higher field than 4a, indicating that the
protons of 4b are more susceptible to the effect. Moreover,
the signals of the phenylene protons, Ha and Hb, of 4a were
broadened, suggesting that the movement of the pendant
groups is conformationally restricted. To ascertain the
spectral change more precisely in a less polar solvent under
the conditions independent of perturbation by hydrogen
bonding with the solvent, the porphyrins 5a and 5b soluble
in a less polar solvent were studied. The porphyrins 5a and
1
5b showed similar H NMR spectral behavior in CDCl3 as
observed in 4, namely, the pendant groups of 5b are more
influenced by the ring-current effect of the porphyrin ring
than those of 5a. Taking the similar spectral inclination
between 4 in DMSO-d6 and 5 in CDCl3 into account, the
pendant groups of 4a and 4b are likely to be magnetically
present in a conformation similar to 5a and 5b, respectively.
These results are in contrast to the finding that the difference
in the effect between the propyl-substituted porphyrins 7a
and 7b was much smaller.
should be noted that the Soret band was slightly red-shifted
with the lower molar coefficient in both cases of 4a and 4b
in THF, as compared with 7a and 7b (Fig. 1). Furthermore,
the Soret and Q bands of 4b were broadened in comparison
with those of 4a, again being in contrast to the lack of
typical spectral difference between the atropisomers 7. The
Soret and Q bands of 5 in ClCH2CH2Cl were also red-
shifted with the lower absorbance as observed in 4.
The electronic environment of these porphyrins was
investigated by absorption spectra as shown in Table 2. It

K. Saito, T. Hirao / Tetrahedron 58 (2002) 7491–7501
7493
Table 1. Chemical shifts of 4, 5 and 7–9 (400 MHz)
Compound
Solvent (mM)
Ha
Hb
Hc
Hd
4a
4b
5a
5b
7a
7b
8
DMSO-d6 (1.0)
DMSO-d6 (1.0)
CDCl3 (0.75)
CDCl3 (0.75)
CDCl3 (0.75)
CDCl3 (0.75)
DMSO-d6 (4.0)
CDCl3 (3.0)
6.15–6.35 (br)
6.77 (d)
6.36 (d)
6.63 (d)
6.42 (d)
6.82–6.92a
6.68 (d)
7.14 (dd)
6.97 (dd)
4.04–4.24a
5.29 (br)
3.69 (d)
2.33–2.28
2.18–2.13
7.46 (d)
4.99 (d)
5.61 (br)
4.67 (d)
0.25 (qt)
20.09 (qt)
6.93 (d)
7.09 (d)
6.90–7.00 (m)
9
7.49 (d)
7.05 (d)
7.23–7.30a
Chemical shifts in ppm from residual solvents as an internal standard.
a
Chemical shift was not determined because of overlap with the signals of other protons.
Table 2. Absorption maxima lmax and molar extinction coefficient log 1 of 4–7
Compound
Solvent
lmax (nm) (log 1)
Da
Porphyrin
p–pp
Soret
Qy(1,0)
Qy(0,0)
Qx(1,0)
Qx(0,0)
b
4a
4b
5a
5b
6a
6b
7a
7b
7a
7b
THF
THF
325 (5.15)
325 (5.16)
297 (5.00)
297 (4.98)
428 (5.33)
430 (5.23)
429 (5.33)
429 (5.16)
428 (5.44)
429 (5.38)
426 (5.47)
426 (5.47)
426 (5.45)
426 (5.44)
517 (4.32)
517 (4.26)
518 (4.26)
518 (4.17)
517 (4.35)
517 (4.34)
517 (4.34)
516 (4.34)
516 (4.34)
516 (4.32)
–
–
–
–
590 (3.84)
588 (3.81)
589 (3.76)
588 (3.71)
589 (3.86)
587 (3.85)
591 (3.82)
591 (3.83)
592 (3.86)
593 (3.84)
644 (3.45)
643 (3.46)
644 (3.37)
642 (3.20)
644 (3.46)
642 (3.37)
648 (3.23)
647 (3.30)
647 (3.44)
648 (3.45)
b
b
ClCH2CH2Cl
ClCH2CH2Cl
ClCH2CH2Cl
ClCH2CH2Cl
ClCH2CH2Cl
ClCH2CH2Cl
THF
b
548 (3.66)
548 (3.64)
549 (3.66)
548 (3.66)
548 (3.74)
549 (3.73)
THF
Measured in 5.0£1026 M solution.
a
D: phenylenediamine pendant group.
The lmax was not detected due to the broadening.
b
The spectral difference between the aaaa and abab
1
isomers observed in H NMR and absorption spectra is
moieties of the pendant groups. It is consistent with the
1
broad signals in H NMR spectra.
probably accounted for as follows. The pendant groups of
the abab isomer might be in equilibrium with the
conformers, in which one or more strands lean toward the
porphyrin ring. The equilibrium of the conformers might be
related to the distortion and fluctuation of the porphyrin ring
as indicated by the broadened Soret and Q bands.11 On the
other hand, such a conformation is less accessible in the
aaaa isomer probably due to the steric crowdedness, being
accompanied by the restricted motion of the phenylene
Molecular dynamics calculation also supports the above-
mentioned conformation of 5a and 5b. In one of the most
stable conformations of the abab isomer 5b, the pendant
groups lean toward the porphyrin ring, which is more
distorted from planarity than that of the aaaa isomer 5a.
The reference porphyrin 12 bearing one anilinoanilino
pendant group was prepared from 10 as illustrated

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K. Saito, T. Hirao / Tetrahedron 58 (2002) 7491–7501
2.3. Electrochemistry
The electrochemical behavior of these porphyrins was
studied by cyclic or differential pulse voltammetry (Table
3). In the cyclic voltammograms of 4, the redox processes
attributable to the phenylenediamine and porphyrin
moieties were observed as illustrated in Scheme 3. Although
the oxidation potentials of the phenylenediamine moieties
of 4a and 4b were not largely different, they are more
cathodic than that of 8. A similar trend was observed in the
case of 5a bearing the anilinoanilino pendant groups, and 9
(Fig. 2). It should be noted that the porphyrin 12 exhibited
the ca. 100 mV anodic oxidation potential of the anilino-
anilino moiety. This shift might be based on the character-
istics of the present p-conjugated system, which suggests a
possibility of an electronic interaction between the pendant
groups on the porphyrin scaffold.13
Figure 1. Absorption spectra in THF (5.0£1026 M) of porphyrins 4a (—),
4b (– – –), and 7a (–·–·–).
Scheme 2.
in Scheme 2. In the 1H NMR spectrum of 12 in CD2Cl2, the
signals of the phenylene protons, Ha and Hb, of the pendant
group were observed in a higher field (d¼4.19 and 4.92,
respectively) as observed in the abab isomer 5b.12 These
results support the above-mentioned conformation of 5b, in
which the pendant groups and porphyrin ring are present in
close proximity.
Table 3. Redox potentials of the porphyrins and reference compounds
Compound (mM)
E (Por/Porz2
)
E (D/Dzþ a
)
E (Dzþ/D2þ
)
4a (0.25)b
4b (0.25)b
5a (0.25)c
5b (0.25)c
7a (0.25)b
7b (0.25)b
8 (1.0)b
21.66
21.64
21.65
21.63
21.63
21.60
20.12
20.10
þ0.28
þ0.28
þ0.24
þ0.25
20.02
þ0.36
þ0.38
þ0.33
9 (1.0)c
12 (1.0)c
21.73
Potentials, V vs Fc/Fcþ; solv. THF containing 0.1 M Bu4NClO4.
a
D: phenylenediamine moiety.
Measured by cyclic voltammetry (scan rate¼100 mV s21).
Figure 2. Differential pulse voltammogram of 5a. [5a]¼2.5£1024 M, Solv.
THF containing 0.1 M Bu4NClO4; scan rate: 20 mV s21; pulse width:
50 ms.
b
c
Measured by differential pulse voltammetry (scan rate¼20 mV s21).

K. Saito, T. Hirao / Tetrahedron 58 (2002) 7491–7501
7495
Scheme 3.
2.4. Fluorescence emission spectroscopy
The fluorescence emission spectroscopy with excitation of
the Q(1,0) band was studied. Noteworthy is that the
emission from the porphyrin moiety observed in 7 was
almost completely quenched (,1%) in the case of both
atropisomers 4a and 4b. Contrary to 4, a similar
quenching did not occur with 6 bearing the anilino
pendant groups. Quenching of the emission of 4
appears to depend on the phenylenediamine function of
the pendant group. This process is consistent with the
difference in the redox potentials of each unit. In the case of
4a, the photoinduced intramolecular electron transfer
from the phenylenediamine moiety D to the excited singlet
state of the porphyrin 1Porp is thermodynamically
feasible.14 The quenching behavior of 4b is explained
similarly.
The emission of 5a or 5b was quenched as observed in 4 (ca.
1%). On the contrary, 12 showed emission with ca. 50%
intensity as compared with that of 7 (Fig. 3). The quenching
in 5 and 12 is also based on the photoinduced intramolecular
electron transfer from the phenylenediamine moiety to the
excited singlet state of the porphyrin. The difference
Figure 3. Fluorescence emission spectra in THF (5.0£1026 M) of
porphyrins 5a,b (– – –), 7a (—), and 12 (–·–·–) with excitation at
Qy(1,0) band.

7496
K. Saito, T. Hirao / Tetrahedron 58 (2002) 7491–7501
Scheme 4.
observed between 5 and 12 might be reflected by the
p-conjugated system of 5, in which the pendant group
undergoes the more facile oxidation.
3. Conclusion
The porphyrins and the corresponding zinc complexes
bearing dimensionally oriented p-conjugated pendant
groups were synthesized and characterized. The structural
and electronic characteristics depend on the atropisomers
bearing the aaaa and abab pendant groups. The relatively
fast photoinduced intramolecular electron transfer from the
phenylenediamine moiety to the excited singlet state of the
porphyrin moiety was demonstrated in both atropisomers.
These p-conjugated systems are of potential use in a variety
of photoreflactive electron transfer systems such as
photocatalysis.
2.5. Zinc complexation
The formation of the zinc complex of 5a was performed by
treatment with zinc(II) acetate dihydrate to give Zn-5a
quantitatively (Scheme 4). In the zinc complexation, a
zinc(II) species is likely to be introduced selectively from
the side opposite to the phenylenediamine strand side
because the corresponding abab atropisomer 5b was
metallated with less efficiency in less than 24% yield.
1
In the H NMR spectra of Zn-5a, the phenylene protons of
the pendant moiety were not largely shifted in comparison
with the corresponding free base 5a. The broad signals of
the phenylene protons close to the porphyrin moiety of Zn-
5a were observed as described in 5a, suggesting a similar
structural circumstance of the pendant groups.
4. Experimental
4.1. General
All reagents and solvents were purchased from commercial
sources and were further purified by the standard methods, if
necessary. Thin-layer chromatography was carried on a
Merck Kiesegel 60F254. Melting points were determined on
a Yanagimoto Micromelting Point Apparatus and were
uncorrected. Infrared spectra were recorded on a Horiba
The oxidation potential of the phenylenediamine pendant
groups of Zn-5a (þ0.29 V vs Fc/Fcþ), which was not
changed by complexation, was more cathodic than that of
Zn-12 (þ0.38 V). Furthermore, the fluorescence emission
of the porphyrin moiety of Zn-5a was quenched with more
ease than that of Zn-12 as observed in the free base 5 and 12.
The four-pendant group effect was again observed with the
zinc complexes.
1
FT-720. H NMR or 13C NMR spectra were recorded on a
Varian INOVA 600 spectrometer (600 MHz) or a JEOL
JNM-GSX-400 spectrometer (400 MHz) with a residual
solvent as an internal standard. Mass spectra were
recorded on a PerSeptive Biosystems Voyager RP
(MALDI-TOF, a dithranol matrix) or a JEOL JMS-DX-
303 (FAB, m-nitrobenzyl alcohol matrix) mass
spectrometer. Absorption spectra were taken on a HITACHI
An aaaa complex, in which four pendant groups are
located on one side of the porphyrin plane, is considered to
accommodate a coordination ligand on the other side.15

K. Saito, T. Hirao / Tetrahedron 58 (2002) 7491–7501
7497
U-3000 spectrophotometer at 5.0£1026 M concentration in
ClCH2CH2Cl or THF at 308C. Fluorescence spectra were
taken on a Shimadzu RF-5300PC spectrofluorophotometer
at 5.0£1026 M concentration in deaerated THF at room
temperature. The cyclic and differential pulse voltammetry
measurements were performed on a BAS CV-50W
voltammetry analyzer with a three-electrode system
consisting of a highly polished glassy carbon working
electrode (BAS), a platinum auxiliary electrode (BAS), and
an Ag/AgNO3 (0.01 M) reference electrode (BAS) in
deaerated THF containing 0.1 M Bu4NClO4 as a
supporting electrolyte at room temperature. Potentials are
given vs. Fc/Fcþ. The molecular dynamics calculation was
performed using Discover 3 program of the Insight II
molecular-modeling package from Molecular Simulations
Inc.
4.1.2. meso-Tetrakis[2-(carboxymethoxy)naphthyl]por-
phyrin (2). Porphyrin 2 was prepared by hydrolysis of 1
as reported in a literature.9 In a 100 mL round bottom flask,
3.0 mL of aqueous NaOH (1 M, 3.0 mmol) was added to the
THF solution of 1a (73 mg, 0.060 mmol), and the mixture
was stirred overnight at room temperature. The solvent was
evaporated to dryness. The residue was dissolved in water,
and then 10% (v/v) acetic acid in water was added to the
solution until the solution was neutralized and the solid
deposited. The solid was filtrated and dried under vacuum to
give 2a in 92% yield. Formation of 2a was confirmed by
1
disappearance of signals for four ethyl groups in the H
NMR spectrum. The porphyrin 2b was synthesized by the
same procedure for 2a. These products were used for further
synthesis without purification.
4.1.3. N-(4-Acetylaminophenyl)-N0-(4-aminophenyl)-1,4-
phenylenediamine (3). Procedure 1: A 200 mL round
bottom flask with a dropping funnel was charged with
N,N0-bis(40-aminophenyl)-1,4-phenylenediamine17 (1.45 g,
5.00 mmol) in THF (20 mL) under argon and the solution
was cooled to 08C. Triethylamine (1 mL) was added, and
then 40 mL of a THF solution of acetic anhydride (510 mg,
5.00 mmol) was added dropwise. After stirring at 08C for
1 h, the reaction mixture was dropped to 500 mL of water to
reprecipate the solid mixture of N,N0-bis(40-aminophenyl)-
4.1.1. meso-Tetrakis[2-(ethoxycarbonylmethoxy)-
naphthyl]porphyrin (1). 2-(Ethoxycarbonylmethoxy)-
naphthalenecarbaldehyde (2.58 g, 10.0 mmol) and Ph4PCl
(11.6 mg, 0.0310 mmol) were added to 100 mL of CH2Cl2
in a 200 mL round bottom flask under argon. Pyrrole
(671 mg, 10.0 mmol) and then 1.0 mL of a stock solution of
BF3·OEt2 in CH2Cl2 (1.0 M, 1.0 mmol) were added. After
stirring at room temperature for 30 min, DDQ (1.71 g,
7.50 mmol) was added. The dark brown mixture was stirred
for 60 min, and then treated with 1 mL of triethylamine. The
mixture was concentrated and the residue was washed with
150 mL of methanol. The crude product was purified by
column chromatography on silica gel eluting with CH2Cl2
to give the porphyrin 1 as a mixture of the four atropisomers
(abab, aabb, aaab, and aaaa, in the order of elution) in
30% yield. The four atropisomers were separated by further
column chromatography on silica gel using solvents with
gradient from CH2Cl2 to CH2Cl2–ethyl acetate (20:1 v/v).
Furthermore, the aaaa isomer (1a) and the abab isomer
(1b) were purified by recrystallization from CH2Cl2-
methanol. 1a: mp 290–2918C; Rf¼0.10 (SiO2, CH2Cl2);
IR (KBr) 3318, 3058, 2979, 2927, 1756, 1735, 1508, 1288,
1,4-phenylenediamine,
N-(4-acetylaminophenyl0)-N0-(4-
aminophenyl)-1,4-phenylenediamine, and N,N -bis(40-
acetylaminophenyl)-1,4-phenylenediamine. The column
chromatography on silica gel eluting with ethyl acetate,
followed by further reprecipitation from hexane (200 mL),
gave 3 in 48% yield (total yield from p-phenylenediamine
was 12%). Procedure 2: 3 was also prepared by oxidative
coupling of p-phenylenediamine (0.97 g, 9.0 mmol) with
N-acetyl-N0-phenyl-1,4-phenylenediamine (1.70 g, 7.5 mmol)
using the same procedure for the preparation of N,N0-bis(40-
aminophen0yl)-1,4-phenylenediamine. In this reaction,
N-acetyl-N -phenyl-1,4-phenylenediamine was added as a
10 mL of the DMF solution. Total yield (60%) of 3 from
p-phenylenediamine was higher as compared with that
obtained in the procedure 1. 3: mp 201–2038C; Rf¼0.28
(SiO2, ethyl acetate); IR (KBr) 3363, 3302, 3039, 1650,
1
1200 cm21; H NMR (400 MHz, CDCl3) d 8.51 (bs, 8H),
8.25 (d, 4H, J¼9.1 Hz), 8.01 (d, 4H, J¼8.2 Hz), 7.58 (d, 4H,
J¼9.1 Hz), 7.33 (dd, 4H, J¼8.2, 6.8 Hz,), 7.00 (dd, 4H,
J¼8.6, 6.8 Hz), 6.90 (d, 4H, J¼8.6 Hz) 4.37 (s, 8H), 3.96 (q,
8H, J¼7.1 Hz), 0.97 (t, 12H, J¼7.1 Hz), 22.14 (bs, 2H);
13C NMR16 (CDCl3, 150 MHz) 169.1, 156.0, 137.9, 130.4,
129.0, 127.6, 127.4, 126.6, 125.8, 123.9, 114.6, 112.7, 66.8,
60.9, 13.9 ppm; MS (MALDI-TOF) m/z 1222.4 (Mþ); UV–
vis (ClCH2CH2Cl) labs (log 1) 425 (5.55), 516 (4.37), 547
(3.69), 590 (3.88), 644 (3.27) nm; Anal. calcd for
C76H62N4O12·0.5H2O: C, 74.07; H, 5.15, N, 4.55. Found:
C, 74.02; H, 5.07; N, 4.42. 1b: mp 285–2878C; Rf¼0.63
(SiO2, CH2Cl2); IR (KBr) 3321, 3060, 2960, 2931, 1757,
1740, 1506, 1286, 1201 cm21; 1H NMR (400 MHz, CDCl3)
d 8.52 (bs, 8H), 8.25 (d, 4H, J¼9.2 Hz), 8.03 (d, 4H,
J¼8.2 Hz), 7.57 (d, 4H, J¼9.2 Hz), 7.34 (dd, 4H, J¼8.2,
6.9 Hz), 6.98 (dd, 4H, J¼8.6, 6.9 Hz), 6.88 (d, 4H,
J¼8.6 Hz), 4.38 (s, 8H), 3.93 (q, 8H, J¼7.1 Hz), 0.93 (t,
12H, J¼7.1 Hz), 22.12 (bs, 2H); 13C NMR (CDCl3,
150 MHz) 169.0, 155.8, 138.0, 130.4, 128.9, 127.7, 127.4,
126.4, 125.6, 123.8, 114.3, 112.6, 66.5, 60.9, 13.9 ppm; MS
(MALDI-TOF) m/z 1222.6 (Mþ); Anal. calcd for
C76H62N4O12: C, 74.62; H, 5.11; N, 4.58. Found: C,
74.42; H, 5.10; N, 4.47.
1605, 1550, 1504, 1288, 1226, 872, 825 cm21; H NMR
1
(600 MHz, DMSO-d6) d 9.62 (bs, 1H), 7.51 (bs, 1H), 7.33
(d, 2H, J¼8.9 Hz), 7.20 (bs, 1H), 6.88 (d, 2H, J¼8.5 Hz),
6.81 (d, 2H, J¼8.9 Hz), 6.79–6.75 (m, 4H), 6.51 (d, 2H,
J¼8.5 Hz), 4.64 (bs, 2H), 1.98 (s, 3H); 13C NMR (150 MHz,
DMSO-d6) 167.6, 143.0, 141.5, 140.5, 134.5, 133.4, 130.7,
120.9, 120.8, 120.4, 116.0, 115.0, 23.94 ppm; MS (FAB)
m/z 332 (Mþ); Anal. calcd for C20H20N4O: C, 72.27; H,
6.06; N, 16.86. Found: C, 71.88; H, 6.21; N, 16.41.
4.1.4. meso-Tetrakis-[2-[[[4-[4-(4-acetylaminoanilino)-
anilino]phenyl]carbamoyl]methoxy]naphthyl]porphyrin
(4). In a 100 mL round bottom flask with a reflux condenser,
a mixture of 2a (50.0 mg, 0.0450 mmol) and 1,10-carbo-
nyldiimidazole (43.8 mg, 0.270 mmol) in THF (20 mL) was
stirred at room temperature for 1.5 h. Then, a THF solution
(20 mL) of 3 (120 mg, 0.360 mmol) was added to the
reaction mixture, which was stirred at refluxing temperature
for 2 days. After the reaction completed, the reaction
mixture was evaporated in vacuo. 4a was isolated in 58%
yield by column chromatography of the residue on silica gel

7498
K. Saito, T. Hirao / Tetrahedron 58 (2002) 7491–7501
using solvents with gradient from ethyl acetate to ethyl
acetate–methanol (19:1 v/v) and reprecipitation from
THF–ether. 4b was synthesized from 2b by the same
procedure for 4a. Isolation by column chromatography of
the residue on silica gel using solvents with gradient from
ethyl acetate to ethyl acetate–methanol (9:1 v/v) and
recrystallization from THF–methanol gave 4b in 56%
yield. 4a: mp 276–2788C; Rf¼0.58 (SiO2, ethyl acetate–
methanol¼5:1 v/v); IR (KBr) 3379, 3325, 3062, 1674, 1612,
CDCl3) d 8.62 (bs, 8H), 8.27 (d, 4H, J¼9.2 Hz), 8.12 (d, 4H,
J¼8.3 Hz), 7.50–7.43 (m, 8H), 7.33 (d, 4H, J¼9.2 Hz),
7.31–7.24 (m, 4H), 7.14 (dd, 8H, J¼8.0, 7.3 Hz), 6.82 (t,
4H, J¼7.3 Hz), 6.63 (d, 8H, J¼8.0 Hz), 5.78 (bs, 4H), 5.61
(br, 8H), 5.29 (br, 8H), 5.20 (bs, 4H), 3.62 (bs, 8H), 21.80
(bs, 2H); 13C NMR (150 MHz, CDCl3) 164.6, 155.2, 142.8,
138.4, 137.0, 131.4, 129.2, 129.0, 127.9, 127.4, 127.4,
124.3, 124.0, 120.3, 119.6, 116.6, 113.8, 112.5, 66.8 ppm;
MS (MALDI-TOF) m/z 1777.1 (MþH)þ; Anal. calcd for
C116H86N12O8·H2O: C, 77.66; H, 4.94; N, 9.37. Found: C,
77.53; H, 4.96; N, 9.53. 5b: mp 1678C (decomp.); Rf¼0.34
(SiO2, CH2Cl2–ethyl acetate¼1:1 v/v); IR (KBr) 3384,
3356, 3315, 3053, 2918, 2845, 1680, 1595, 1512, 1497,
1512, 1304, 1273, 1111, 818, 748 cm21
;
1H NMR
(400 MHz, DMSO-d6) d 9.66 (bs, 4H), 8.55 (bs, 8H), 8.34
(d, 4H, J¼9.2 Hz), 8.11 (d, 4H, J¼8.4 Hz), 8.04 (bs, 4H),
7.68 (d, 4H, J¼9.2 Hz), 7.65 (bs, 4H), 7.44 (bs, 4H), 7.40–
7.33 (m, 12H), 7.12 (dd, 4H, J¼8.8, 6.8 Hz), 6.92–6.82 (m,
20H), 6.77 (d, 8H, J¼8.8 Hz), 6.35–6.15 (br, 16H), 4.26
(bs, 8H), 2.09 (bs, 12H), 22.06 (bs, 2H); 13C NMR
(150 MHz, DMSO-d6) 167.3, 164.7, 155.5, 140.3, 140.2,
136.9, 136.6, 136.0, 130.9, 130.6, 128.5, 128.1, 127.7, 126.9,
126.2, 123.4, 122.8, 120.4, 119.8, 118.9, 118.5, 115.7, 114.5,
113.9, 113.0, 66.4, 23.7 ppm; MS (MALDI-TOF) m/z 2370.8
(MþH)þ; Anal. calcd for C148H118N20O12·3H2O: C, 73.37; H,
5.16; N, 11.56. Found: C, 73.14; H, 5.06; N, 11.44. 4b: mp
257–2608C; Rf¼0.45 (SiO2, ethyl acetate–methanol¼5:1
v/v); IR (KBr) 3377, 3319, 3028, 1672, 1612, 1504, 1304,
1267,1093,822,748 cm21;1HNMR(400 MHz,DMSO-d6)d
9.70 (bs, 4H), 8.46 (bs, 8H), 8.19 (d, 4H, J¼9.2 Hz), 8.07 (d,
4H, J¼8.4 Hz), 7.53–7.46 (m, 8H), 7.42–7.30 (m, 12H), 7.09
(bs, 4H), 6.98(d, 4H, J¼8.5 Hz), 6.86–6.74(m, 12H), 6.68 (d,
8H, J¼8.3 Hz), 6.36 (d, 8H, J¼8.3 Hz), 5.21 (bs, 4H), 4.99 (d,
8H, J¼8.3 Hz), 4.24–4.04 (m, 16H), 2.03 (bs, 12H), 21.66
(bs, 2H); 13C NMR (150 MHz, DMSO-d6) 167.5, 163.5,
155.1, 140.2, 140.0, 136.5, 136.2, 135.2, 130.9, 128.2, 127.7,
126.8, 126.6, 123.6, 122.7, 120.6, 118.9, 118.1, 117.7, 115.7,
114.2, 113.4, 112.5, 66.4, 23.8 ppm; MS (MALDI-TOF) m/z
2368.9 (Mþ); Anal. calcd for C148H118N20O12·3H2O: C,
73.37; H, 5.16; N, 11.56. Found: C, 73.40; H, 4.98; N,
11.40.
1
1325, 1269, 1093, 806, 748 cm21; H NMR (400 MHz,
CDCl3) d 8.54 (bs, 8H), 8.29 (d, 4H, J¼9.1 Hz), 8.07 (d, 4H,
J¼8.3 Hz), 7.37 (dd, 4H J¼8.3, 6.8 Hz), 7.31–7.25 (m,
8H), 6.97 (dd, 8H, J¼8.6, 7.3 Hz), 6.89 (dd, 4H, J¼8.6,
6.8 Hz), 6.67 (t, 4H, J¼7.3 Hz), 6.42 (d, 8H, J¼8.6 Hz),
4.94 (bs, 4H), 4.68–4.66 (m, 12H), 4.05 (bs, 8H), 3.69 (d,
8H, J¼8.6 Hz), 21.58 (bs, 2H); 13C NMR (150 MHz,
CDCl3) 163.5, 154.8, 142.5, 137.6, 136.7, 131.3, 129.0,
128.9, 128.7, 127.8, 127.6, 127.4, 124.4, 123.6, 120.0,
117.6, 116.2, 115.5, 114.7, 114.1, 112.9, 66.9 ppm; MS
(MALDI-TOF) m/z 1777.4 (MþH)þ; Anal. calcd for
C116H86N12O8·H2O: C, 77.66; H, 4.94; N, 9.37. Found: C,
77.76; H, 4.89; N, 9.34.
4.1.6. meso-Tetrakis[2-(phenylcarbamoyl)methoxy]-
naphthylporphyrin (6). Porphyrins 6 were similarly
prepared as mentioned in the preparation of 4. 6a was
isolated in 48% yield by column chromatography on silica
gel using solvents with gradient from CH2Cl2 to CH2Cl2–
ethyl acetate (10:3 v/v) and recrystallization from THF–
ether. 6b was isolated in 82% yield by column chromato-
graphy on silica gel using solvents with gradient from
CH2Cl2 to CH2Cl2–ethyl acetate (7:3 v/v) and recrystalliza-
tion from THF–methanol or THF–ether. 6a: mp 296–
2988C; Rf¼0.48 (SiO2, CH2Cl2–ethyl acetate¼1:1 v/v); IR
(KBr) 3384, 3320, 3059, 2922, 1691, 1601, 1531, 1508,
1442, 1333, 1271, 1240 cm21; 1H NMR (400 MHz, CDCl3),
d 8.65 (bs, 8H), 8.36 (d, 4H, J¼9.1 Hz), 8.13 (d, 4H,
J¼8.1 Hz), 7.50–7.46 (m, 12H), 7.30–7.27 (m, 4H), 6.34 (t,
4H, J¼7.6 Hz), 5.91 (dd, 8H, J¼8.0, 7.6 Hz), 5.80 (bs, 4H),
5.36 (d, 8H, J¼8.0 Hz), 3.74 (bs, 8H), 21.72 (bs, 2H); 13C
NMR (150 MHz, CDCl3) 164.8, 155.1, 138.1, 135.4, 131.6,
129.0, 127.9, 127.5, 127.4, 127.3, 124.4, 124.1, 123.2,
118.2, 113.7, 112.3, 66.9 ppm; MS (MALDI-TOF) m/z
1412.9 (MþH)þ; Anal. calcd for C92H66N8O8·H2O: C,
77.30; H, 4.79; N, 7.84. Found: C, 77.25; H, 4.67; N, 7.81.
6b: mp .3008C; Rf¼0.59 (SiO2, CH2Cl2–ethyl
acetate¼1:1 v/v); IR (KBr) 3384, 3319, 3057, 2917, 2854,
1697, 1601, 1533, 1508, 1444, 1335, 1269, 1240 cm21; 1H
NMR (400 MHz, CDCl3) d 8.62 (bs, 8H), 8.35 (d, 4H,
J¼9.0 Hz), 8.08 (d, 4H, J¼8.3 Hz), 7.51 (d, 4H, J¼9.0 Hz),
7.39 (dd, 4H, J¼8.3, 7.0 Hz), 7.07 (d, 4H, J¼8.4 Hz), 6.81
(dd, 4H, J¼8.4, 7.0 Hz), 6.02 (t, 4H, J¼7.5 Hz), 5.13 (dd,
8H, J¼8.1, 7.5 Hz), 4.96 (bs, 4H), 4.37 (bs, 8H), 4.07 (d,
8H, J¼8.1 Hz), 21.44 (bs, 2H); 13C NMR (150 MHz,
CDCl3) 163.9, 154.9, 136.8, 134.8, 131.5, 128.9, 127.7,
127.5, 127.5, 126.5, 124.4, 123.4, 122.7, 116.8, 113.9,
112.8, 67.2 ppm; MS (MALDI-TOF) m/z 1412.7 (MþH)þ;
Anal. calcd for C92H66N8O8·H2O: C, 77.30; H, 4.79; N,
7.84. Found: C, 77.50; H, 4.64; N, 7.81.
4.1.5. meso-Tetrakis[2-[(4-anilinophenyl)carbamoyl]-
methoxy]naphthylporphyrin (5). The porphyrins 5a and
5b were prepared as mentioned in the preparation of 4. 5a
was isolated in 42% yield by column chromatography on
silica gel using solvents with gradient from CH2Cl2 to
CH2Cl2–ethyl acetate (8:2 v/v) and recrystallization from
THF–methanol. 5b was isolated in 82% yield by column
chromatography on silica gel using solvents with gradient
from CH2Cl2 to CH2Cl2–ethyl acetate (7:3 v/v) and
recrystallization from THF–methanol.
For another procedure, 5a was also synthesized by
condensation using EDCl·HCl as the condensation agent.
EDCI·HCl (22.3 mg, 0.117 mmol) and HOBt (59.4 mg,
0.117 mmol) were added to a THF solution (10 mL) of 2
(21.6 mg, 0.0194 mmol) at room temperature and the
mixture solution was stirred for 30 min. Then, a THF
solution (15 mL) of N-phenyl-1,4-phenylenediamine
(21.5 mg, 0.117 mmol) was added to the reaction mixture,
which was stirred for 24 h and then evaporated. Purification
of the crude product by the above-mentioned procedure
gave 5a in 68% yield. 5a: mp 135–1408C; Rf¼0.13 (SiO2,
CH2Cl2–ethyl acetate¼1: 1 v/v); IR (KBr) 3381, 3356,
3325, 3053, 2922, 2852, 1684, 1595, 1512, 1496, 1325,
1
1271, 1109, 1076, 800, 748 cm21; H NMR (400 MHz,

K. Saito, T. Hirao / Tetrahedron 58 (2002) 7491–7501
7499
4.1.7. meso-Tetrakis[2-(propylcarbamoyl)methoxy]-
naphthylporphyrin (7). Porphyrins 7 were prepared as
mentioned in the preparation of 4. 7a was isolated in 81%
yield by column chromatography on silica gel using
solvents with gradient from chloroform–ethyl acetate (1:1
v/v) and recrystallization from THF–ether. 7b was similarly
isolated in 46% yield. 7a: mp 287–2888C; Rf¼0.025 (SiO2,
CH2Cl2–ethyl acetate¼1:1 v/v); IR (KBr) 3410, 3319,
3060, 2962, 2931, 2873, 1684, 1590, 1541, 1508, 1338,
preparation of 8 and it was isolated in 83% yield by column
chromatography of the residue on silica gel using solvents
with gradient from CH2Cl2 to CH2Cl2–ethyl acetate (9:1
v/v) and recrystallization from CHCl3–hexane. 9: mp 181–
1828C; Rf¼0.75 (SiO2, CH2Cl2–ethyl acetate¼8.5:1 v/v);
IR (KBr) 3392, 3290, 3040, 2915, 1680, 1660, 1597, 1514,
1500, 1313, 1255, 1219, 1182, 1060, 1039, 841, 742 cm21
;
1H NMR (400 MHz, CDCl3) d 8.23 (bs, 1H), 7.85–7.77 (m,
3H), 7.52–7.48 (m, 3H), 7.41 (ddd, 1H, J¼8.4, 6.8, 1.5 Hz),
7.30–7.23 (m, 4H), 7.10–7.04 (m, 4H), 6.93 (dt, 1H, J¼7.3,
1.1 Hz), 5.69 (bs, 1H), 4.76 (s, 2H); 13C NMR (150 MHz,
CDCl3) 165.9, 154.8, 143.2, 140.2, 134.3, 130.3, 130.1,
129.6, 129.4, 127.7, 127.1, 126.9, 124.5, 121.8, 120.9,
118.8, 118.0, 117.4, 107.9, 67.6 ppm; MS (FAB) m/z 368
(Mþ); Anal. calcd for C24H20N2O2: C, 78.24; H, 5.47; N,
7.60. Found: C, 78.16; H, 5.51; N, 7.63.
1
1270, 1219, 1107, 810, 748 cm21; H NMR (400 MHz,
CDCl3) 8.51 (bs, 8H), 8.34 (d, 4H, J¼9.2 Hz), 8.07 (d, 4H,
J¼8.3 Hz), 7.65 (d, 4H, J¼9.2 Hz), 7.39 (dd, 4H, J¼8.3,
6.7 Hz), 7.07 (dd, 4H, J¼8.6, 6.7 Hz), 6.91 (d, 4H,
J¼8.6 Hz), 5.27 (bs, 4H), 4.42 (bs, 8H), 2.33–2.28 (m,
8H), 0.25 (qt, 8H, J¼7.3, 7.3 Hz), 20.17 (t, 12H,
J¼7.3 Hz), 22.07 (bs, 2H); 13C NMR (150 MHz, CDCl3)
167.6, 155.6, 155.6, 137.5, 131.5, 129.2, 127.8, 127.4,
127.1, 125.0, 124.9, 124.4, 114.0, 113.3, 68.8, 39.8, 21.6,
10.2 ppm; MS (MALDI-TOF) m/z 1276.6 (MþH)þ; Anal.
calcd for C80H74N8O8: C, 75.33; H, 5.85; N, 8.79. Found: C,
75.38; H, 5.88; N, 8.78. 7b: mp 288–2898C; Rf¼0.32 (SiO2,
CH2Cl2–ethyl acetate¼1:1 v/v); IR (KBr) 3410, 3317,
3062, 2962, 2931, 2870, 1681, 1589, 1527, 1512, 1335,
4.1.10. 5-[2-(Ethoxycarbonylmethoxy)naphthyl]-
10,15,20-triphenylporphyrin (10). 2-(Ethoxycarbonyl-
methoxy)naphthalenecarbaldehyde (647 mg, 2.5 mmol),
benzardehyde (901 mg, 7.5 mmol) and Ph4PCl (11.6 mg,
0.0310 mmol) were added to 100 mL of CH2Cl2 in a
200 mL round bottom flask under argon. Pyrrole (671 mg,
10.0 mmol) and then 1.0 mL of a stock solution of
BF3·(OEt)2 in CH2Cl2 (1.0 M, 1.0 mmol) were added.
After stirring at room temperature for 30 min, DDQ
(1.71 g, 7.50 mmol) was added. The dark brown mixture
was stirred for 60 min, and then treated with 1 mL of
triethylamine. The crude product was purified by chroma-
tography on silica gel using CH2Cl2 to afford four fractions
mainly. The first fraction was 5,10,15,20-tetraphenyl-
porphyrin (5.5% yield). The porphyrin 10 was eluted as
the second fraction (22%). The third and fourth fractions
were found to be two atropisomers (aa and ab) of 5,10-
bis[2-(ethoxycarbonylmethoxy)naphthyl-15,20-diphenyl-
porphyrin (2.3 and 3.0%, respectively). 10: mp .3008C;
Rf¼0.55 (SiO2, CH2Cl2); IR (KBr) 3315, 3053, 2955, 2925,
1
1265, 1211, 1095, 810, 748 cm21; H NMR (400 MHz,
CDCl3) d 8.52 (bs, 8H), 8.35 (d, 4H, J¼9.2 Hz), 8.10 (d, 4H,
J¼8.3 Hz), 7.60 (d, 4H, J¼9.2 Hz), 7.43 (dd, 4H, J¼8.3,
6.8 Hz), 7.11 (dd, 4H, J¼8.6, 6.8 Hz), 6.97 (d, 4H,
J¼8.6 Hz), 4.95 (br, 4H), 4.41 (bs, 8H), 2.18–2.13 (m,
8H), 20.096 (qt, 8H, J¼7.3, 7.3 Hz), 20.52 (t, 12H,
J¼7.3 Hz), 22.05 (bs, 2H); 13C NMR (150 MHz, CDCl3)
167.5, 155.2, 137.4, 131.5, 129.1, 127.9, 127.2, 127.0, 124.7,
124.4, 113.5, 113.2, 66.1, 39.6, 21.4, 9.9 ppm; MS (MALDI-
TOF) m/z 1276.4 (MþH)þ; Anal. calcd for C80H74N8O8: C,
75.37; H, 5.87; N, 8.86. Found: C, 75.38; H, 5.88; N, 8.78.
4.1.8. 2-[[[4-[4-(4-Acetylaminoanilino)anilino]phenyl]-
carbamoyl]methoxy]naphthalene (8). In a 100 mL round
bottom flask, a mixture of 2-(carboxymethoxy)naphtha-
lene13 (61 mg, 0.30 mmol) and 1,10-carbonyldiimidazole
(73 mg, 0.45 mmol) in THF was stirred at room temperature
for 1.5 h. Then, 20 mL of a THF solution of 3 (100 mg,
0.30 mmol) was added to the reaction mixture, which was
stirred for 12 h. After the reaction completed, the reaction
mixture was evaporated in vacuum. After addition of CHCl3
(ca. 100 mL), the insoluble solid was filtrated and washed
with CHCl3 to give 8 without further purification in a
quantitative yield. 8: mp 232–2338C; Rf¼0.20 (SiO2,
CHCl3–ethyl acetate¼2:1 v/v); IR (KBr) 3402, 3286,
3140, 3054, 3032, 1680, 1666, 1604, 1512, 1304, 1257,
1
1757, 1736, 1473, 1348, 1193 cm21; H NMR (400 MHz,
acetone-d6) d 8.86 (bs, 4H), 8.75 (d, 2H, J¼4.8 Hz), 8.66
(d, 2H, J¼4.8 Hz), 8.41 (d, 1H, J¼9.1 Hz), 8.31–8.20
(m, 6H), 8.14 (d, 1H, J¼8.3 Hz), 7.89–7.75 (m, 10H),
7.36 (dd, 1H, J¼8.3, 6.7 Hz), 7.01 (dd, 1H, J¼8.5,
6.7 Hz), 6.68 (d, 1H, J¼8.5 Hz), 4.62 (s, 2H), 3.96 (q,
2H, J¼7.1 Hz), 0.97 (t, 3H, J¼7.1 Hz), 22.56 (bs, 2H);
13C NMR (acetone-d6, 150 MHz) 168.8, 156.4, 142.4,
142.3, 138.4, 134.7, 134.6, 131.0, 129.2, 128.3, 128.2,
128.1, 127.2, 127.1, 127.0, 124.5, 124.0, 120.8, 120.3,
120.2, 114.2, 114.0, 65.7, 60.8, 22.8, 13.8 ppm; MS
(MALDI-TOF) m/z 767 (MþH)þ; Anal. calcd for
C52H38N4O3: C, 81.44; H, 4.99, N, 7.31. Found: C,
81.15; H, 5.00; N, 7.28.
1219, 1180, 1018, 1057, 818, 741 cm21
;
1H NMR
(400 MHz, DMSO-d6) d 9.89 (bs, 1H), 9.66 (bs, 1H),
7.90–7.82 (m, 2H), 7.80 (d, 1H, J¼8.3 Hz), 7.77 (bs, 1H),
7.72 (bs, 1H), 7.50–7.40 (m, 3H), 7.40–7.29 (m, 5H),
7.00–6.85 (m, 8H), 4.77 (s, 2H), 1.99 (s, 3H); 13C NMR
(150 MHz, DMSO-d6) 167.7, 165.8, 155.9, 141.4, 140.5,
137.1, 136.5, 134.2, 131.3, 129.9, 129.6, 128.9, 127.7,
127.0, 126.7, 124.1, 121.6, 120.7, 119.5, 118.9, 118.9,
116.1, 115.6, 107.4, 67.5, 24.0 ppm; MS (FAB) m/z 516
(Mþ); Anal. calcd for C32H28N4O3: C, 74.40; H, 5.46; N,
10.85. Found: C, 74.02; H, 5.45; N, 10.90.
4.1.11. 5-[2-(Carboxymethoxy)naphthyl]-10,15,20-tri-
phenylporphyrin (11). Porphyrin 11 was prepared by
hydrolysis of 10 according to the similar procedure to that of
2. The porphyrin 11 was used for the synthesis of 12 without
purification.
4.1.12. 5-[2-[[(4-Anilinophenyl)carbamoyl]methoxy]-
naphthyl]-10,15,20-triphenylporphyrin (12). In a round-
bottom flask with a reflux condenser, EDCI·HCl (23.3 mg,
122 mmol) and HOBt (16.4 mg, 122 mmol) were added to a
THF solution (50 mL) of 11 (60.0 mg, 81.2 mmol) at room
4.1.9. 2-[(4-Anilinophenyl)carbamoyl]methoxynaphtha-
lene (9). Compound 9 was prepared as mentioned in the

7500
K. Saito, T. Hirao / Tetrahedron 58 (2002) 7491–7501
temperature and the mixture solution was stirred for 30 min.
Then, a THF solution (10 mL) of N-phenyl-1,4-phenylene-
diamine (20.6 mg, 122 mmol) was added to the reaction
mixture, which was stirred for 24 h and then evaporated.
Purification of the crude product by column chromato-
graphy on silica gel eluting with CH2Cl2 and further
reprecipitation from CH2Cl2–hexane afforded 12 as a
purple crystal in 74% yield. 12: mp 150–1518C; Rf¼0.20
(SiO2, CH2Cl2); IR (KBr) 3382, 3317, 3054, 2921, 2852,
1687, 1596, 1512, 1496, 1347, 1322, 1269, 1104, 1072, 965,
References
1. Examples for grafting of the p-conjugated polymer or
oligomer chains: (a) Creager, S.; Yu, C. J.; Bamdad, C.;
O’Connor, S.; MacLean, T.; Lam, E.; Chong, Y.; Olsen, G. T.;
Luo, J.; Gozin, M.; Kayyem, J. F. J. Am. Chem. Soc. 1999,
121, 1059. (b) Berlin, A.; Zotti, G.; Schiavon, G.; Zecchin, S.
J. Am. Chem. Soc. 1998, 120, 13453, and references cited
therein. (c) Tour, J. M.; Jones, II., L.; Pearson, D. L.; Lamba,
J. S.; Burgin, T. P.; Whitesides, G. W.; Allara, D. L.; Parikh,
A. N.; Atre, S. J. Am. Chem. Soc. 1995, 117, 9529. (d) Garnier,
F.; Yassar, A.; Hajaoui, R.; Horowitz, G.; Deloffre, F.; Servet,
B.; Ries, S.; Alnot, P. J. Am. Chem. Soc. 1993, 115, 8716.
(e) Cammarata, V.; Atanasoska, L.; Miller, L. L.; Kolaskie,
C. J.; Stallman, B. J. Langmuir 1992, 8, 876. (f) Yamamoto,
T.; Kanbara, T.; Mori, C. Synth. Met. 1990, 38, 399.
1
802 cm21; H NMR (600 MHz, CD2Cl2) d 8.85 (br, 4H),
8.79 (d, 2H, J¼4.3 Hz), 8.62 (d, 2H, J¼4.3 Hz), 8.39 (dd,
1H, J¼9.2, 0.7 Hz), 8.27 (d, 1H, J¼7.1 Hz), 8.20 (d, 2H,
J¼7.1 Hz), 8.16 (d, 1H, J¼8.5 Hz), 8.03 (d, 1H, J¼7.1 Hz),
7.99 (d, 2H, J¼7.1 Hz), 7.83–7.67 (m, 9H), 7.65 (d, 1H,
J¼9.2 Hz), 7.48 (ddd, 1H, J¼8.5, 6.6, 1.1 Hz), 7.37 (d, 1H,
J¼8.5 Hz), 7.22 (ddd, 1H, J¼8.5, 6.6, 1.1 Hz), 7.11 (dd, 2H,
J¼8.5, 7.3 Hz), 6.83 (dt, 1H, J¼7.3, 1.1 Hz), 6.43 (dd, 2H,
J¼8.5, 1.1 Hz), 5.26 (bs, 1H), 4.97 (bs, 1H), 4.92 (d, 2H,
J¼8.7 Hz), 4.53 (bs, 2H), 4.16 (d, 2H, J¼8.7 Hz), 22.54
(bs, 2H); 13C NMR (150 MHz, CD2Cl2) 164.6, 155.9, 143.1,
142.3, 142.1, 138.4, 137.5, 135.1, 134.9, 134.8, 131.6,
129.7, 129.5, 129.3, 128.2, 128.1, 127.8, 127.5, 127.2,
127.1, 127.0, 125.7, 124.7, 121.4, 120.8, 120.6, 118.7,
117.0, 116.9, 114.6, 112.4, 68.7 ppm; MS (MALDI-TOF)
m/z 906 (MþH)þ; Anal. calcd for C62H44N6O2·0.2CH2Cl2:
C, 81.02; H, 4.85; N, 9.11. Found: C, 81.28; H, 5.14; N,
8.84.
2. (a) Wu¨rthner, F.; Vollmer, M. S.; Effenberger, F.; Emele, P.;
Meyer, D. U.; Port, H.; Wolf, H. C. J. Am. Chem. Soc. 1995,
117, 8090, and references cited therein. (b) Li, F.; Yang, S. I.;
Ciringh, Y.; Seth, J.; Martin, III., C. H.; Singh, D. L.; Kim, D.;
Birge, R. R.; Bocian, D. F.; Holten, D.; Lindsey, J. S. J. Am.
Chem. Soc. 1998, 120, 10001. (c) Ward, M. D. Chem. Soc.
Rev. 1997, 26, 365. (d) Guldi, D. M. Chem. Soc. Rev. 2002, 31,
22.
3. (a) Vannelli, T. A.; Karpishin, T. B. Inorg. Chem. 1999, 38,
2246. and reference cited therein. (b) Reimers, J. R.; Hall,
L. E.; Crossly, M. J.; Hush, N. S. J. Phys. Chem. A 1999, 103,
4385. (c) Novak, B. H.; Lash, T. D. J. Org. Chem. 1998, 63,
3998. (d) Arnold, D. P.; Heath, G. A.; James, D. A. J.
Porphyrins Phthalocyanines 1999, 1, 5. (e) Taylor, N. P.;
Wylie, A. P.; Huuskonen, J.; Anderson, H. L. Angew. Chem.,
Int. Ed. 1998, 37, 986.
4.1.13. Zinc complexation of 5a to Zn-5a. A THF solution
(5 mL) of 5a (24 mg, 14 mmol) was added to a methanol
solution of zinc(II) acetate dihydrate (13 mg, 70 mmol),
which was refluxed under argon for 12 h and then
evaporated. Purification of the crude product by column
chromatography on alumina (acetone–methanol 95:5 v/v)
gave Zn-5a in 90% yield. Zn-5a: mp 223–2258C (uncor-
rected); Rf¼0.60 (SiO2, ethyl acetate); IR (KBr) 3380, 3051,
4. For example, porphyrin–quinone cyclophanes: (a) Staab,
H. A.; Hauck, R.; Popp, B. Eur. J. Org. Chem. 1998, and
references cited therein. (b) Osuka, A.; Maruyama, K.;
Hirayama, S. Tetrahedron 1989, 45, 4815. Porphyrin–
fullerene systems: (c) Cheng, P.; Wilson, S. R.; Schuster,
D. I. Chem. Commun. 1999, 89. (d) Bourgeois, J.-P.;
Diederich, F.; Echegoyen, L.; Nierengarten, J.-F. Helv.
Chim. Acta 1998, 81, 1835. (e) Dietel, E.; Hirsch, A.;
1
1678, 1593, 1511, 1496, 1323, 1271, 1109, 799 cm21; H
NMR (600 MHz, CD2Cl2) d 8.71 (bs, 8H), 8.28 (d, 4H,
J¼9.2 Hz), 8.12 (d, 4H, J¼8.5 Hz), 7.45 (dd, 4H, J¼8.5,
6.6 Hz), 7.41 (d, 4H, J¼8.7 Hz), 7.35 (d, 4H, J¼9.2 Hz),
7.23 (dd, 4H, J¼8.7, 6.6 Hz), 7.13 (dd, 8H, J¼8.2, 7.3 Hz),
6.80 (t, 4H, J¼7.3 Hz), 6.64 (d, 8H, J¼8.2 Hz), 5.71 (bs,
4H), 5.67–5.60 (br, 8H), 5.28 (bs, 4H), 5.24–5.12 (br,
8H), 3.60 (bs, 8H); MS (TOF) m/z 1838.8 (Mþ2H)þ;
UV–vis (CH2Cl2) lmax (log 1 ) 549 (4.34), 430 (5.45),
303 (4.95); Anal. calcd for C116H84N12O8Zn·H2O: C,
75.01; H, 4.67; N, 9.05. Found: C, 74.90; H, 4.78; N,
8.91.
¨
Eichhorn, E.; Rieker, A.; Hackbarth, S.; Roder, B. Chem.
Commun. 1998, 1981. (f) Baran, P. S.; Monaco, R. R.; Khan,
A. U.; Schuster, D. I.; Wilson, S. R. J. Am. Chem. Soc. 1997,
119, 8363. (g) Ranasinghe, M. G.; Oliver, A. M.; Rothenfluh,
D. F.; Salek, A.; Paddon-Row, M. N. Tetrahedron Lett. 1996,
37, 4797. (h) Imahori, H.; Hagiwara, K.; Aoki, M.; Akiyama,
T.; Taniguchi, S.; Okada, T.; Shirakawa, M.; Sakata, Y. J. Am.
Chem. Soc. 1996, 118, 11771. (i) Drovetskaya, T.; Reed, C. A.
Tetrahedron Lett. 1995, 36, 7971. (j) Liddell, P. A.; Sumida,
J. P.; Macpherson, A. N.; Noss, L.; Seely, G. R.; Clark, K. N.;
Moore, A. L.; Moore, T. A.; Gust, D. Photochem. Photobiol.
1994, 60, 537.
Acknowledgments
5. Vollmer, M. S.; Wu¨rthner, F.; Effenberger, F.; Emele, P.;
Meyer, D. U.; Stu¨mpfig, T.; Port, H.; Wolf, H. C. Chem. Eur.
J. 1998, 4, 260.
We thank Dr J. Setsune, Professor at Kobe University for
helpful discussions. We also thank Mrs T. Muneishi and
Mrs Y. Miyaji for helpful discussion in 1H NMR
experiments. The use of the facilities of the Analytical
Center, Faculty of Engineering, Osaka University, is
acknowledged. This work was financially supported in
part by a Grant-in-Aid for Scientific Research on Priority
Areas from the Ministry of Education, Culture, Sports,
Science and Technology, Japan.
6. Mikami, S.; Sugiura, K.; Sakata, Y. Chem. Lett. 1997, 833.
7. Hirao, T.; Saito, K. Tetrahedron Lett. 2000, 41, 1413.
8. Li, F.; Yang, K.; Tyhonas, J. S.; MacCrum, K. A.; Lindsey,
J. S. Tetrahedron 1997, 33, 12339.
9. Arai, T.; Kobata, K.; Mihara, H.; Fujimoto, T.; Nishino, N.
Bull. Chem. Soc. Jpn 1995, 68, 1989.
10. Hayashi, T.; Miyahara, T.; Aoyama, Y.; Kobayashi, M.;
Ogoshi, H. Pure Appl. Chem. 1994, 66, 797.

K. Saito, T. Hirao / Tetrahedron 58 (2002) 7491–7501
7501
11. Broadening of absorption by distortion of the porphyrin ring
has been reported in the strapped porphyrins; (a) Simonis, U.;
Walker, F. A.; Lee, P. L.; Hanquet, B. J.; Meyerhoff, D. J.;
Scheidt, W. R. J. Am. Chem. Soc. 1987, 109, 2659. (b) Wagner,
R. W.; Johnson, T. E.; Lindsey, J. S. Tetrahedron 1997, 53,
6755.
ecules has been reported; (a) Iyoda, M.; Hasegawa, M.;
Kuwatani, Y.; Nishikawa, H.; Fukami, K.; Nagase, S.;
Yamamoto, G. Chem. Lett. 2001, 1146. (b) Kaikawa, T.;
Takimiya, K.; Aso, Y.; Otsubo, T. Org. Lett. 2000, 2, 4197.
14. The driving force of photoinduced charge separation DGcs is
estimated to be 20.38 eV by the equation: DGcs¼[E(D/
Dzþ)2E(Por/Porz2)]2E 0–0, where E 0–0 is the energy of
photoexcitation (4a: 1.92 eV).
12. The single-crystal X-ray structure analysis demonstrated that
the pendant group of 12 leans toward the porphyrin ring
despite poor results. The pendant group of 12 is likely to adopt
a variety of conformational structures in a solution, including
the one, in which the group is present outside of the ring-
current effect area.
15. Hirao, T.; Saito, K. Synlett 2002, 415.
16. In 13C NMR spectra of the porphyrin compounds described
here, Ca and/or Cb carbons of the four pyrrole rings were not
detected due to the broadening by N–H tautomerism.
17. Wei, Y.; Yang, C.; Ding, T. Tetrahedron Lett. 1996, 37, 731.
13. For example, cathodic shift of the oxidation potential of the
close face-to-face arranged redox-active p-conjugated mol-