Synthesis and properties of meso-monophenyltetrabenzoporphine and its zinc complex

Article abstract of DOI:10.1023/A:1020715202738

meso-Monophenyltetrabenzoporphine and its zinc complex were synthesized starting from 3-(3-oxo-2,3-dihydro-1H-isoindol-1-ylidenemethyl)-1H-isoindol-1-one. The effect of unsymmetrical meso-substitution on physical and spectral properties of the products is

Full text of DOI:10.1023/A:1020715202738

Russian Journal of General Chemistry, Vol. 72, No. 7, 2002, pp. 1119 1122. Translated from Zhurnal Obshchei Khimii, Vol. 72, No. 7, 2002,
pp. 1198 1201.
Original Russian Text Copyright
2002 by Galanin, Kudrik, Shaposhnikov.
Synthesis and Properties
of meso-Monophenyltetrabenzoporphine and Its Zinc Complex
N. E. Galanin, E. V. Kudrik, and G. P. Shaposhnikov
Ivanovo State University of Chemical Engineering, Ivanovo, Russia
Received July 5, 2000
Abstract meso-Monophenyltetrabenzoporphine and its zinc complex were synthesized starting from
3-(3-oxo-2,3-dihydro-1H-isoindol-1-ylidenemethyl)-1H-isoindol-1-one. The effect of unsymmetrical meso-
substitution on physical and spectral properties of the products is discussed. The results of quantum-chemical
calculations suggest spatial distortion of the porphyrin macroring.
meso-Aryl-substituted tetrabenzoporphines have benzoporphinato)zinc(II) and meso-substituted deriva-
been studied for almost 20 years. First representatives
of this group of compounds were reported in 1981
by Kopranenkov et al. [1] who synthesized the zinc
complex of meso-tetraphenyltetrabenzoporphine (I)
from phthalimide and phenylacetic acid in the pres-
ence of zinc acetate. The authors also assumed forma-
tion of partially meso-substituted products, i.e., zinc
complexes of mono-, di-, and triphenyltetrabenzopor-
phines. Their formation may be explained by the pres-
ence in the reaction mixture of acetate ion as a source
of methylene component. However, such compounds
were neither isolated nor characterized.
tives I IV]; among these, compounds I IV are char-
acterized by increased solubility.
Therefore, the goal of this work was to develop
a new selective procedure for preparing meso-mono-
phenyltetrabenzoporphine (V) and its zinc complex IV
and to examine their physical and spectral properties.
We previously reported [4] on the synthesis of III
from 3-(3-oxo-2,3-dihydro-1H-isoindol-1-ylidenemeth-
yl)-1H-isoindol-1-one (VI) which is an intermediate
product in the preparation of tetrabenzoporphines and
is readily obtained by reaction of phthalimide with
zinc(II) acetate dihydrate. Compound VI was also
used to synthesize meso-monophenyltetrabenzopor-
phine (V) according to Scheme 1.
Later on, the synthesis of meso-phenyl-substituted
tetrabenzoporphines was studied in detail by Ichimura
et al. [2]. By fusion of potassium phthalimide with
zinc phenylacetate at 360 C for 1 h, the authors ob-
tained a mixture of zinc complexes of meso-phenyl-
substituted tetrabenzoporphines. Chromatographic sep-
aration of the mixture gave 3% of (meso-tetraphenyl-
tetrabenzoporphinato)zinc(II) (I), 5.5% of (meso-tri-
phenyltetrabenzoporphinato)zinc(II) (II), and 2% of
(meso-diphenyltetrabenzoporphinato)zinc(II) (III). All
the compounds were characterized by electronic ab-
The reaction of compound VI with phenylacetic
acid and zinc acetate yielded a mixture of three main
products: (tetrabenzoporphinato)zinc(II) and com-
pounds IV and III. In addition, small amounts of I
and II were detected, presumably originating from
partial thermal decomposition of VI. The mixture
was separated by Soxhlet extraction of complexes
I IV with benzene and subsequent column chroma-
tography. Compounds I, II, and III were identified
by comparing their electronic absorption spectra with
those reported in [2, 4]. meso-Monophenyltetraben-
zoporphine (V) was obtained by demetalation of IV
via treatment of its solution in tetrachloroethane with
concentrated hydrochloric acid. The purity of IV and
V was checked by TLC, and their structure was con-
1
sorption, H NMR, and field desorption mass spectra.
The formation of (meso-monophenyltetrabenzopor-
phinato)zinc(II) (IV) was also presumed [2], but this
product was not detected. Compound IV was syn-
thesized for the first time by Chang et al. [3] via con-
densation of phthalimide with sodium acetate in the
presence of phenylacetic acid and a zinc salt, and elec-
tronic absorption spectrum of IV was recorded. How-
ever, the procedure described in [3] has considerable
disadvantages, including low yield of the target prod-
uct and difficulties in the separation of a mixture of
approximately equal amounts of five products [(tetra-
1
firmed by elemental analyses and H NMR, electronic
absorption, and FAB mass spectra.
The mass spectrum of IV contained no ion peaks
with m/z 724, 800, and 876, indicating the absence of
1
impurities I III. In the H NMR spectrum of IV, sig-
1070-3632/02/7207-1119$27.00 2002 MAIK Nauka/Interperiodica

1120
GALANIN et al.
O
PhCH2COOH,
Zn(OAc)2 2H2O
N
.
N
NH HN
N
N
.
HCl
N Zn N
NH
.
.
N
O
V
IV
V
Scheme 1.
nals from three meso-protons were observed in the re-
gion 12.5 ppm. Three groups of signals were pres-
ent in the region 8.2 7.2 ppm. A triplet at 8.2
8.0 ppm belongs to two ortho-protons of the meso-
phenyl fragment, and a multiplet at 8.0 7.8 ppm
corresponds to three protons in the meta- and para-
components are observed for V. Also, the bands have
different intensities. There are some differences in the
mode of splitting of the Soret band. The splitting is
stronger in the spectrum of V. As might be expected,
the main absorption bands in the electronic absorption
spectrum of V are red shifted relative to the corre-
positions. Protons of the isoindole fragments appear sponding bands of tetrabenzoporphine, though the
in the region 7.5 7.2 ppm (16H): eight protons in
positions 3 and 6 give rise to a multiplet at 7.5
7.4 ppm, and signals from those in positions 4 and 5
shift is insignificant (2 3 nm). This may be due to
positive inductive effect of the meso-substituent and
reduced symmetry of molecular orbitals of nonplanar
compound V.
(8H) are observed at
7.4 7.2 ppm.
Compounds IV and V are dark blue crystalline
substances which are better soluble in organic solvents
(such as benzene, chloroform, and acetone) than un-
substituted tetrabenzoporphine owing to the presence
of a bulky phenyl group.
We performed quantum-chemical calculations of
molecule V by the AM1 semiempirical method with
full geometry optimization [5]. Some results are given
in the table.
According to the calculations, molecule V has in
fact nonplanar structure. One of the isoindole frag-
ments (C12C16C17C18C19C20C15C14N13) is turned by
an angle of more than 35 relative to the macroring
plane. Obviously, this is due to the steric effect of
the meso-phenyl substituent, which reduces the point
symmetry group of the macroring to Cs .
The electronic absorption spectrum of V (see figure)
considerably differs from the spectra of other meso-
phenyl-substituted tetrabenzoporphines and resembles
that of unsubstituted tetrabenzoporphine. The long-
wave absorption band in the spectrum of V is split,
which is also typical of tetrabenzoporphine. However,
in the spectrum of the latter the long-wave absorption
band is split into three components, while only two
Thus, we have developed a new method for syn-
thesizing the zinc complex of meso-monophenyltetra-
benzoporphine, which ensures higher yield of the
target product and simpler purification procedure.
EXPERIMENTAL
The electronic absorption spectra were measured
on a Hitachi UV-2000 spectrophotometer. The mass
spectrum (fast atom bombardment in a m-nitrobenzyl
alcohol matrix) was obtained on a Finnigan HSQ-30
1
mass spectrometer. The H NMR spectrum was re-
corded on a Bruker WM-200 instrument (Autonomous
University of Madrid, Spain).
3-(3-Oxo-2,3-dihydro-1H-isoindol-1-ylidenemeth-
yl)-1H-isoindol-1-one (VI). A mixture of 16 g of
Electronic absorption spectrum of meso-monophenyltetra-
benzoporphine (V) in benzene.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 72 No. 7 2002

SYNTHESIS AND PROPERTIES OF meso-MONOPHENYLTETRABENZOPORPHINE
1121
phthalimide and 23 g of zinc(II) acetate dihydrate was
placed in a quartz test tube; it was heated to 230 C
and kept for 20 min at that temperature. After cooling,
the melt was ground and washed in succession with
a 10% solution of sodium hydroxide, water, 10% hy-
drochloric acid, and water again until washings be-
came neutral. The product was dried and dissolved
in acetone, and the solution was chromatographed
on a column packed with alumina (activity grade II)
using acetone as eluent. Yield 5.1 g (27%), mp 230
232 C. The product is soluble in acetone, pyridine,
DMF, and acetic acid and insoluble in water. Elec-
tronic absorption spectrum (pyridine), max, nm (D):
357 (0.38), 515 (0.30), 550 (0.26). Found, %: C 74.40;
H 3.70; N 10.19. C17H10N2O2. Calculated, %: C 74.45;
H 3.67; N 10.21.
Bond lengths (d) and bonda ( ) and torsion angles ( ) in
the molecule of meso-monophenyltetrabenzoporphine (V)
according to the results of AM1 calculations
8
9
43
42
44
45
7
2
10
41
46
17
6
5
4
1
3
34
32
40
37
11 12
13
35
36
N
16
39
38
18
19
33
NH HN
15
N
14
22 21
26
27
20
23
31 24
25
30
29
28
Bond
d,
Torsion angle
, deg
(meso-Monophenyltetrabenzoporphinato)zinc(II)
(IV). A mixture of 1 g of VI, 1.36 g of phenylacet-
ic acid, and 1.85 g of zinc(II) acetate dihydrate was
placed in a quartz test tube. The test tube was heated
to 350 C and kept for 25 min at that temperature. The
melt was cooled, ground, and extracted with benzene
in a Soxhlet apparatus. The extract was evaporated to
dryness, the dark green powder-like residue was dis-
solved in benzene, and the solution was applied to
a column packed with aluminum oxide (Brockmann
activity grade II). The column was eluted with ben-
zene hexane (1 : 5), and a fraction containing a mix-
ture of compounds I and II (according to TLC data)
was collected. The subsequent elution with benzene
hexane acetone (1 : 5 : 2) gave a fraction containing
compounds III and IV. This fraction was subjected to
repeated chromatography on alumina using benzene
hexane ethyl acetate (1 : 10 : 2) as eluent. We thus
isolated 0.08 g (10% with respect to initial compound
VI, 45% of the overall amount of complexes soluble
in benzene) of compound IV as a dark blue powder.
Rf 0.38 (benzene, Silufol). The product is readily sol-
uble in DMF, benzene, toluene, and acetone and in-
soluble in water and dilute aqueous acids and alkalis.
Electronic absorption spectrum (benzene), max, nm
C1 C2
1.44
1.33
1.44
1.37
1.46
1.38
1.39
1.43
1.36
1.43
1.33
1.44
1.36
1.41
1.40
1.36
C1C2N3C4
174.22
177.74
14.67
60.63
175.50
177.50
35.0
C2 N3
C2N3C4C11
N3 C4
N3C4C11C12
C4C11C12N13
C11C12N13C14
C12N13C14C21
N13C14C21C22
C14C21C22N23
C21C22N23C24
C22N23C24C31
N23C24C31C32
C24C31C32N33
C31C32N33C34
C32N33C34C1
C4 C11
C11 C12
C12 N13
N13 C14
C14 C21
C21 C22
C22 N23
N23 C24
C24 C31
C31 C32
C32 N33
N33 C34
C34 C1
1.4
170.0
174.0
0.4
5.1
179.4
179.3
a
34
1
2
4 11 12
Bond angles, deg:
14 21 22
C
C C 126.1, C C
C
120.5,
24 31 32
C
C
C
125.6, C
C
C
125.2.
added, and the mixture was stirred for 2 h. It was
then diluted with water, and the organic phase was
separated, washed with water, aqueous ammonia, and
water again until washings became neutral, dried, and
evaporated. The residue was dissolved in benzene,
and the solution was chromatographed on a column
packed with alumina (activity grade II) using ben-
zene hexane ethyl acetate (1 : 5 : 1) as eluent. Com-
pound V was isolated as a dark blue powder. Yield
0.08 g (71%). Rf 0.46 (benzene, Silufol). The product
is readily soluble in DMF, benzene, toluene, and ace-
tone and insoluble in water and dilute aqueous acids
and alkalis. Electronic absorption spectrum (benzene),
max, nm (log ): 665 (4.06), 607 (4.11), 598 (4.21),
565 (3.88), 472 (3.92), 432 (4.98), 417 (4.79), 398
(4.08). Found, %: C 86.28; H 4.81; N 9.46. C42H26N4.
Calculated, %: C 85.98; H 4.47; N 9.55.
1
(log ): 625 (4.61), 587 (3.82), 427.5 (5.17). H NMR
spectrum (CDCl3), , ppm: 12.5 s (3H), 8.2 8.0 t
(2H), 8.0 7.8 m (3H), 7.5 7.4 m (8H), 7.4 7.2 m
(8H). Mass spectrum (FAB), m/z: 651.2 [M + 3H]+,
650.2 [M + 2H]+, 649.2 [M + H]+, 648.2 [M]+, 647.2
[M H]+, 572.1 [M C6H5]+. Found, %: C 78.12;
H 3.85; N 8.45. C42H24N4Zn. Calculated, %: C 77.60;
H 3.72; N 8.62.
meso-Monophenyltetrabenzoporphine (V). Com-
plex IV, 0.1 g, was dissolved in 10 ml of tetrachloro-
ethane, 5 ml of concentrated hydrochloric acid was
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 72 No. 7 2002

1122
GALANIN et al.
2. Ichimura, K., Sakuragi, M., Morii, H., Yasuike, M.,
ACKNOWLEDGMENTS
Toba, Y., Fukui, M., and Ohno, O., Inorg. Chim. Acta,
The authors are grateful to Prof. T. Torrez (Auto-
nomous University of Madrid, Spain) for his help in
measuring the H NMR and mass spectra.
1991, vol. 186, no. 1, pp. 95 101.
3. Chang, P.J., Chen, Y.R., and Chuang, C.E., Hetero-
cycles, 1992, vol. 34, no. 1, pp. 1 4.
1
4. Kudrik, E.V., Islyaikin, M.K., and Frantseva, S.V.,
REFERENCES
Zh. Obshch. Khim., 1997, vol. 67, no. 7, pp. 1202 1205.
5. Dewar, M.J.S., Zoebisch, E.G., Healy, E.F., and
Stewart, J.J.P., J. Am. Chem. Soc., 1985, vol. 107,
no. 13, p. 3902.
1. Kopranenkov, V.N., Dashkevich, S.N., and Luk’ya-
nets, E.A., Zh. Obshch. Khim., 1981, vol. 51, no. 11,
pp. 2513 2517.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 72 No. 7 2002