Metal complexes of phthalocyanine structural analogs with oxygen- or nitrogen-containing heterorings. Synthesis and properties

Article abstract of DOI:10.1023/B:RUGC.0000039096.32453.12

Nucleophilic substitution of the bromine atom and nitro group in 4-bromo-5-nitrophthalodinitrile and reduction of 4-benzoylamino-5- nitrophthalodinitrile gave, respectively, tribenzo[b,e,g][1,4]dioxocine-7,8- dicarbonitrile and 2-phenylbenzimidazole-5,6-d

Full text of DOI:10.1023/B:RUGC.0000039096.32453.12

Russian Journal of General Chemistry, Vol. 74, No. 5, 2004, pp. 787 790. Translated from Zhurnal Obshchei Khimii, Vol. 74, No. 5, 2004,
pp. 855 859.
Original Russian Text Copyright
2004 by Maizlish, Shaposhnikov, Balakireva, Zharnikova, Abramov, Ivanovskii, Smirnov.
Metal Complexes of Phthalocyanine Structural Analogs
with Oxygen- or Nitrogen-containing Heterorings.
Synthesis and Properties
V. E. Maizlish, G. P. Shaposhnikov, O. V. Balakireva,
M. A. Zharnikova, I. G. Abramov, S. A. Ivanovskii, and A. V. Smirnov
Ivanovo State University of Chemistry and Technology, Ivanovo, Russia
Received April 10, 2002
Abstract Nucleophilic substitution of the bromine atom and nitro group in 4-bromo-5-nitrophthalodinitrile
and reduction of 4-benzoylamino-5-nitrophthalodinitrile gave, respectively, tribenzo[b,e,g][1,4]dioxocine-7,8-
dicarbonitrile and 2-phenylbenzimidazole-5,6-dicarbonitrile. These compounds were used to synthesize new
structural analogs of phthalocyanine, having oxygen- and nitrogen-containing heterorings, (tetratribenzo[b,e,g]-
[1,4]dioxocino[7,8-b,g,l,q]-5,10,15,20-tetraazaporphyrinato)copper(II) and (23,73,123,173-tetraphenyl-tetra-
benzimidazolo[5,6-b,g,l,q]-5,10,15,20-tetraazaporphyrinato)cobalt(II). Spectral properties of the resulting
complexes were studied.
A large group of modified phthalocyanines (Pc)
consists of their structural analogs in which the por-
phyrazine macroring is fused to various heterocycles.
Despite extensive studies, such compounds have been
explored to a much lesser extent, as compared to
phthalocyanines. The available data suggest some
prospects in their practical application [1 4]; therefore,
further studies in this field are necessary, including
those aimed at preparation of new derivatives. The
present communication continues the series of our
publications on the effect of functional substitution
on various physical and chemical properties of
phthalocyanines [5 12]. It reports on the synthesis
and properties of metal complexes derived from
phthalocyanine structural analogs in which the
peripheral benzene rings are fused to oxygen- or
nitrogen-containing heterocycles, namely (tetra-tri-
benzo[b,e,g][1,4]dioxocino[7,8-b,g,l,q]-5,10,15,20-
tetraazaporphyrinato)copper(II) (I) and (23,73,123,
173-tetraphenyl-tetra-benzimidazolo[5,6-b,g,l,q]-
5,10,15,20-tetraazaporphyrinato)cobalt(II) (II).
N
O
O
HN
H5C6
C6H5
N
N
O
O
N
O
O
HN
N
N
N
N
Cu
N
Co
N
N
N
N N
N
N N
N
N
NH
H5C6
C6H5
O
O
NH
N
I
II
1070-3632/04/7405-0787 2004 MAIK Nauka/Interperiodica

788
MAIZLISH et al.
dark green powder, which is insoluble in water and in
dilute aqueous acids and alkalies and soluble in DMF,
-chloronaphthalene, chloroform, benzene, and
acetone. It should be noted that solutions of I in DMF,
chloroform, and benzene undergo coagulation with
time ( 20 min) and become colorless.
D
1
2
3
0.9
0.6
The electronic absorption spectrum of a freshly pre-
pared solution of complex I in DMF contains bands
with their maxima at 629 and 677 nm (see figure).
The absorption bands are diffuse, indicating associa-
tion of the solute. The spectral pattern does not
change on replacement of DMF by benzene or chloro-
form. The spectral curves are typical of associates. In
going to -chloronaphthalene as solvent, the spectrum
is transformed into a single-band one (see figure),
indicating decomposition of the associates into
monomeric species. Here, the first absorption band is
displaced to the red region. The Q band appears at a
longer wavelength, as compared to unsubstituted
phthalocyanine, due to the presence of a dioxocine
ring. As with other phthalocyanine metal complexes,
replacement of the solvent by concentrated sulfuric
acid induces a considerable red shift of the Q band as
a result of protonation of the porphyrazine ring at the
meso-nitrogen atoms.
0.3
500
600
700
800 , nm
Electronic absorption spectra of(tetra-tribenzo[b,e,g][1,4]-
dioxocino[7,8-b,g,l,q]-5,10,15,20-tetraazaporphyrinato)-
copper(II) (I) (c = 1 10 M) in (1) DMF, (2) -chloro-
5
naphthalene, and (3) H SO .
2
4
Copper complex I was synthesized by the nitrile
technique in quinoline using tribenzo[b,e,g][1,4]di-
oxocine-7,8-dicarbonitrile (IV) as initial compound.
4-Bromo-5-nitrophthalodinitrile (III) is a unique
synthon for the preparation of various substituted
phthalodinitrile derivatives due to the presence of two
groups which are very reactive toward nucleophiles.
The bromine atom is usually replaced first [8 13];
however, conditions have been found under which
nucleophilic substitution occurs simultaneously at the
bromine atom and the nitro group [11 14]. Using
2,2 -dihydroxybiphenyl as nucleophile, we obtained
tribenzo[b,e,g][1,4]dioxocine-7,8-dicarbonitrile (IV)
which is necessary for the synthesis of compound I.
Among structural analogs of phthalocyanine, com-
pounds containing peripheral imidazole rings attract
interest [2, 15, 16]. Unfortunately, only few pub-
lished data are available on the synthesis and pro-
perties of such derivatives, presumably because of
difficulties in the preparation of the corresponding
precursors. It is known that benzimidazoles are
formed by reduction and subsequent heterocyclization
of acyl derivatives of o-amino nitro compounds [17].
By reduction of 4-benzoylamino-5-nitrophthalodinit-
rile (V) (which was synthesized by us previously [18])
with tin(II) chloride in concentrated hydrochloric acid
we obtained for the first time 2-phenylbenzimidazole-
5,6-dicarbonitrile (VII). The reduction was carried out
at 70 C (reaction time 3 h). It involved intermediate
formation of amine VI [17], which followed from the
positive diazo test of the reaction mixture during the
process. After 3 h, amino group was no longer de-
tected, indicating completion of heterocyclization.
CN
CN
Br
O2N
III
OH
OH
K2CO3,
DMF
O
NC
NC
O
In the IR spectrum of compound VII we observed
1
an absorption band at 2232 cm
( C N), typical of
IV
the initial dinitrile, while no absorption bands cor-
responding to vibrations of nitro and carbonyl groups
were present. A new absorption band appeared at
680 cm , which is characteristic of a 4,5-disubstituted
imidazole ring [19]. 2-Phenylbenzimidazole-5,6-di-
The complex was purified by reprecipitation from
concentrated sulfuric acid, followed by Soxhlet extrac-
tion with methanol to remove impurities. (Tetratri-
benzo[b,e,g][1,4]dioxocino[7,8-b,g,l,q]-5,10,15,20-
tetraazaporphyrinato)copper(II) (I) was isolated as a
1
carbonitrile (VII) is a light beige substance which,
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 74 No. 5 2004

METAL COMPLEXES OF PHTHALOCYANINE STRUCTURAL ANALOGS
789
SnCl2,
NH
N
NC
NC
NHCOC6H5
NO2
NC
NC
NHCOC6H5
NO2
NC
NC
HCl
C6H5
V
VI
VII
unlike initial phthalodinitrile V, does not melt below
300 C. It is soluble in dilute alkali solutions, as well
as in acetone, isopropyl alcohol, and dimethylform-
amide.
(
max
660 nm, DMF). In going from DMF to con-
centrated sulfuric acid, a strong red shift of the Q
band is observed ( 806 nm) due to protonation of
the molecule. The basic centers in the latter may be
not only phthalocyanine meso-nitrogen atoms but also
nitrogen atoms of the imidazole rings.
max
Benzoylation of benzimidazoles according to
Schotten Baumann is known to result in cleavage of
the imidazole ring and formation of dibenzoyl deriva-
tive of the corresponding o-phenylenediamine [17, 20].
By treatment of 2-phenylbenzimidazole-5,6-dicarbo-
nitrile (VII) with benzoyl chloride in a dilute (1%)
aqueous solution of sodium hydroxide we obtained
4,5-dibenzoylaminophthalodinitrile (VIII).
EXPERIMENTAL
The electronic absorption spectra were recorded
from solutions in organic solvents and concentrated
sulfuric acid at room temperature using a Perkin Elmer
UV-Vis Lambda-20 spectrophotometer ( range 300
1
C6H5COCl,
NaOH
900 nm). The H NMR spectrum of a 5% solution of
NC
NC
NHCOC6H5
NHCOC6H5
compound IV in DMSO-d6 (with TMS as internal
reference) was recorded on a Bruker AC-200P in-
strument at the Institute of Organic Chemistry,
Russian Academy of Sciences (Moscow, Russia).
VII
VIII
Compound VIII is readily soluble in organic sol-
vents (such as acetone and isopropyl alcohol) but,
unlike initial dinitrile VII, is insoluble in dilute
aqueous alkalies and is characterized by a sharp
melting point (232 234 C). The IR spectrum of VIII
retains the C N absorption typical of phthalodinitrile
Tribenzo[b,e,g][1,4]dioxocine-7,8-dicarbonitrile
(IV). 2,2 -Dihydroxybiphenyl, 10 mmol, anhydrous
potassium carbonate, 20 mmol, and 4-bromo-5-nitro-
phthalodinitrile, 10 mmol, were added under stirring
to 30 ml of DMF. The mixture was stirred for 2 h at
90 100 C, cooled to room temperature, and poured
into 100 ml of water. The precipitate was filtered off,
washed with 50 ml of water, and recrystallized from
DMF. Yield 79%, mp 205 206 C. 1H NMR spectrum,
, ppm: 8.15 s (2H, 1-H), 7.50 7.35 m (8H, 2-H, 3-H,
4-H, 5-H, J = 30 Hz). Found, %: C 77.28; H 3.39; N
8.94. C20H10N2O2. Calculated, %: C 77.41; H 3.25;
N 9.03.
1
VII but lacks band in the region 680 cm ; in addition,
1
a carbonyl absorption band appears at 1708 cm .
These data indicate opening of the imidazole ring.
Phthalodinitrile VIII can be used to prepare octa-
4,5-benzoylaminophthalocyanines (see Experimental).
Heating of 2-phenylbenzimidazol-5,6-dicarbonitrile
with cobalt(II) chloride at 320 340 C afforded (23,73,
123,173-tetraphenyl-tetra-benzimidazolo[5,6-b,g,l,q]-
5,10,15,20-tetraazaporphyrinato)cobalt(II) (II). Like
compound I, complex II was purified by reprecipita-
tion from concentrated sulfuric acid, followed by ex-
traction with organic solvents to remove impurities.
The product is readily soluble in DMF, DMSO, and
concentrated sulfuric acid and insoluble in acetone,
benzene, chloroform, and alcohols. Treatment of
complex II with 20% oleum at 60 70 C gives the
corresponding sulfonic acid which acquires solubility
in aqueous ammonia or sodium hydroxide but is less
soluble in DMF and DMSO, as compared to II.
(Tetra-tribenzo[b,e,g][1,4]dioxocino[7,8-b,g,l,q]-
5,10,15,20-tetraazaporphyrinato)copper(II) (I).
Copper(I) chloride, 0.25 mmol, was added to a solu-
tion of 0.9 mmol of tribenzo[b,e,g][1,4]dioxocine-7,8-
dicarbonitrile in 10 ml of quinoline. The mixture was
heated under vigorous stirring to the boiling point,
stirred for 1.5 h at that temperature, cooled to room
temperature, and poured into 50 ml of dilute (1:1)
hydrochloric acid. The precipitate was filtered off,
washed with water until neutral chloride ion-free
washings, and dried at 60 C. The product was re-
precipitated from concentrated sulfuric acid and ex-
tracted with methanol in a Soxhlet apparatus. Yield
25%. Electronic absorption spectrum, max, nm: DMF:
676, 629; chloroform: 680; 612; benzne: 706, 674; -
chloronaphthalene: 685, 654; conc. H2SO4: 822, 727.
Linear fusion of phenylimidazole fragments to the
isoindole moieties of phthalocyanine molecule leads
to a red shift of the Q-band (
714 nm, DMF), as
max
compared to unsubstituted cobalt phthalocyaninate
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 74 No. 5 2004

790
MAIZLISH et al.
Found, %: C 60.9; H 3.0; N 7.9. C80H40CuN8O8.
Calculated, %: C 59.1; H 2.5; N 6.9.
REFERENCES
1. Phthalocyanines: Properties and Applications, Lez-
noff, C.C. and Lever, A.B.P., Eds., New York: VCH,
1989 1996, vols. 1 4.
2. Pardo, C., Yuste, M., and Elguero, J., J. Porphyrins
Phthalocyanines, 2000, vol. 4, no. 5, p. 505.
3. Bekaroglu, O., J. Porphyrins Phthalocyanines, 2000,
vol. 4, no. 5, p. 465.
4. Engelkamp, H. and Nolte, R.J.M., J. Porphyrins
Phthalocyanines, 2000, vol. 4, no. 5, p. 454.
5. Shishkina, O.V., Maizlish, V.E., Shaposhnikov, G.P.,
and Smirnov, R.P., Zh. Obshch. Khim., 1998, vol. 68,
no. 5, p. 860.
6. Balakirev, A.E., Maizlish, V.E., Shaposhnikov, G.P.,
and Smirnov, R.P., Zh. Obshch. Khim., 2000, vol. 70,
no. 4, p. 669.
7. Maizlish, V.E., Balakirev, A.E., Shishkina, O.V., and
Shaposhnikov, G.P., Zh. Obshch. Khim., 2001, vol. 71,
no. 2, p. 274.
8. Shishkina, O.V., Maizlish, V.E., and Shaposhni-
kov, G.P., Zh. Obshch. Khim., 2001, vol. 71, no. 2,
p. 271.
9. Shishkina, O.V., Maizlish, V.E., Kudrik, E.V., Sha-
poshnikov, G.P., and Smirnov, R.P., Zh. Obshch.
Khim., 2000, vol. 70, no. 5, p. 815.
10. Shishkina, O.V., Maizlish, V.E., Kudrik, E.V., Sha-
poshnikov, G.P., and Smirnov, R.P., Zh. Obshch.
Khim., 1999, vol. 69, no. 10, p. 1712.
11. Abramov, I.G., Ivanovskii, S.A., Smirnov, A.V., and
Dorogov, M.V., Izv. Vyssh. Uchebn. Zaved., Ser.
Khim. Khim. Tekhnol., 2000, vol. 43, no. 1, p. 120.
12. Abramov, I.G., Dorogov, M.V., Ivanovskii, S.A.,
Smirnov, A.V., and Abramova, M.B., Mendeleev
Commun., 2000, no. 1, p. 78.
13. Ivanovskii, S.A., Cand. Sci. (Chem.) Dissertation,
Yaroslavl, 2000.
14. Maizlish, V.E., Ivanovskii, S.A., Shaposhnikov, G.P.,
Abramov, I.G., Smirnov, A.V., Bykova, V.V., and
Usol’tseva, N.V., Zh. Obshch. Khim., 2002, vol. 72,
no. 9, p. 1552.
15. Kudrik, E.V., Shaposhnikov, G.P., and Balakirev, A.E.,
Zh. Obshch. Khim., 1999, vol. 69, no. 8, p. 1372.
16. Balakirev, A.E., Cand. Sci. (Chem.) Dissertation,
Ivanovo, 2001.
17. Heterocyclic Compounds, Elderfield, R.C., Ed., New
York: Wiley, 1957, vol. 5.
18. Zharnikova, M.A., Balakirev, A.E., Maizlish, V.E.,
and Shaposhnikov, G.P., Zh. Obshch. Khim., 1999,
vol. 69, no. 11, p. 1870.
2-Phenylbenzimidazole-5,6-dicarbonitrile (VII).
4-Benzoylamino-5-nitrophthalodinitrile (V), 0.8 g,
was added to a solution of 1.7 g of tin(II) chloride in
3 ml of concentrated hydrochloric acid. The mixture
was heated to 70 75 C and was kept for 3 h at that
temperature. Water, 15 ml, was then added, and the
mixture was heated for 30 min on a boiling water bath.
The precipitate was filtered off and washed with water
until neutral washings. The crude product was dis-
solved in 1% aqueous sodium hydroxide, the solution
was filtered off, and the filtrate was acidified with
dilute hydrochloric acid. The precipitate was filtered
off, washed with distilled water until neutral chloride
ion-free washings, and dried at 110 C. Yield 0.5 g
(76%). Found, %: C 73.2; H 3.1; N 22.5. C15H8N4.
Calculated, %: C 73.8; H 3.3; N 22.3.
4,5-Dibenzoylaminophthalodinitrile (VIII). Di-
nitrile VII, 2.0 g, was dissolved in 50 ml of 1%
aqueous sodium hydroxide. The solution was cooled
to 0 2 C, 8 ml of benzoyl chloride and 290 ml of a
1% alkali solution were added in portions over a
period of 1 h, and the mixture was kept for 3 h at that
temperature. The precipitate was filtered off, washed
with water and isopropyl alcohol, and dried at 50
60 C. Yield 1.2 g (40%), mp 232 234 C. Found, %:
C 71.7; H 3.5; N 15.6. C22H14N4O2. Calculated, %: C
72.1; H 3.8; N 15.3.
(23,73,123,173-tetraphenyl-tetra-benzimidazolo-
[5,6-b,g,l,q]-5,10,15,20-tetraazaporphyrinato)co-
balt(II) (II). A mixture of 0.1 g of 2-phenylbenz-
imidazole-5,6-dicarbonitrile and 0.12 mmol of co-
balt(II) chloride was heated to 320 330 C and kept
until the melt solidified. The melt was cooled and
washed with isopropyl alcohol, water, and acetone,
and the product was reprecipitated from concentrated
sulfuric acid. Yield 0.03 g (30%). Electronic absorp-
tion spectrum, max, nm: 714 (DMF); 806 (conc.
H2SO4). Found, %: C 69.1; H 2.9; Co 5.5; N 21.0.
C60H22CoN16. Calculated, %: C 69.6; H 3.1; Co 5.7;
N 21.6.
[2,3,9,10,16,17,23,24-Octakis(benzoylamino)-
phthalocyaninato]cobalt(II). A mixture of 0.5 g of
4,5-dibenzoylaminophthalodinitrile (VIII), 0.06 g of
cobalt(II) chloride, and 0.7 g of benzoic acid was
heated to 180 C and kept for 45 min at that tempera-
ture. The melt was cooled and washed with isopropyl
alcohol, water, and acetone, and the product was re-
precipitated from concentrated sulfuric acid. Yield
19. Nakanishi, K., Infrared Absorption Spectroscopy.
Practical, San Francisco: Holden-Day, 1962.
20. Bamberger, E. and Berle, B., Justus Liebigs Ann.
Chem., 1892, vol. 273, p. 342.
0.2 g (30%). Electronic absorption spectrum,
,
nm: 708 (DMF); 809 (concd. H2SO4). Found, %m: aCx
68.5; H 3.5; Co 3.7; N 14.8. C88H56CoN16O8. Cal-
culated, %: C 69.3; H 3.7; Co 3.9; N 14.7.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 74 No. 5 2004