5-Bromotrimellitic acid and metal phthalocyanines based thereon

Article abstract of DOI:10.1007/s11176-005-0354-3

5-Bromotrimellitic acid, its amide, and corresponding metal phthalocyanines on their basis were synthesized. The electronic absorption spectra of the latter are much affected by the nature of the complexing metal and the solvent.

Full text of DOI:10.1007/s11176-005-0354-3

Russian Journal of General Chemistry, Vol. 75, No. 6, 2005, pp. 970 974. Translated from Zhurnal Obshchei Khimii, Vol. 75, No. 6, 2005,
pp. 1026 1030.
Original Russian Text Copyright
2005 by Kulinich, Shaposhnikov, Gorelov, Doronina.
5-Bromotrimellitic Acid
and Metal Phthalocyanines Based Thereon
V. P. Kulinich, G. P. Shaposhnikov, V. N. Gorelov, and E. A. Doronina
Ivanovo University of Chemical Technology, Ivanovo, Russia
Received January 23, 2004
Abstract 5-Bromotrimellitic acid, its amide, and corresponding metal phthalocyanines on their basis were
synthesized. The electronic absorption spectra of the latter are much affected by the nature of the complexing
metal and the solvent.
Over the past years mixed-substituent phthalo-
cyanines have received much study. They can be used
as dyes, catalysts for redox processes, biologically
active preparations, etc. [1, 2].
stantiated. To prepare 5-bromotrimellitic acid (III),
compound II was oxidized with potassium perman-
ganate in aqueous alkali in the presence of pyridine,
which allowed the reaction to be accomplished in a
homogeneous medium and the reaction time to be
much shortened. The precipitate of manganese dioxide
was filtered off, and the filtrate was concentrated and
acidified to precipitate compound III as colorless
crystals. The product was filtered off and transformed
in part into imide IV [8].
Of particular interest are phthalocyanines contain-
ing in the benzene rings carboxy groups together with
other substituents. Carboxy-substituted phthalocya-
nines are characteristically readily soluble in aqueous
media and polar organic solvents, which extends the
field of their investigation and practical application.
Compounds III and IV were identified by ele-
At present ample information has been ac-
cumulated, concerning carboxy-substituted phthalo-
cyanines with varied number and position of carboxy
groups [3 5]. However, the information of mixed-
substituent complexes containing carboxy groups
together with other substituents is limited on account
of the lack of reliable methods of their synthesis.
Known methods [5] involve introduction of substi-
tuents into tetracarboxy-substituted metal phthalo-
cyanines and are unsuitable for preparing complexes
with preset number and position of new substituents.
Therefore, to develop synthetic approaches to sub-
stituted trimellitic (4-carboxyphthalic) acids as start-
ing materials for metal phthalocyanines is an urgent
problem.
mental analysis and IR spectroscopy. The IR spectra
1
(Fig. 1) contain an absorption band at 670 680 cm ,
formed by stretching vibrations of the C Br bond, as
well as a band of stretching vibrations of the C=O
bond in the carboxy groups in aromatic dicarboxylic
acids and their imides. Furthermore, the spectrum of
compound III contains two bands (1350 1370 and
1
1610 1615 cm ) from stretching vibrations of bonds
in the COO-group [9].
Bromo-and-carboxy-substituted metal phthalo-
cyanines V VII were synthesized by the urea
method, specifically, by heating compound III or IV
with urea, corresponding metal chlorides, acetates, or
oxalates, and a catalytic amount of NH4MoO4. Com-
plexes V VII were isolated and purified by a scheme
used in the synthesis of halo-and-sulfo-substituted
phthalocyanines [10]. It should be noted that starting
from compound III by the above procedure we could
only prepare complex V (Co2+). With imide IV, we
could also prepare complexes VI and VII (Cu2+ and
Fe2+) and complex V in a higher yield than with acid
III.
Here we report on the synthesis of 5-bromotri-
mellitic acid, its imide, and mixed-substituent metal
phthalocyanines on their basis.
The starting compound, 1,2,4-trimethylbenzene (I),
was brominated by the procedure in [6] in dry chloro-
form at 0 2 C. With account for the charge distribu-
tion on benzene carbon atoms in compound I and
thermodynamic characteristics of formation of pos-
Metal complexes V VII are dark blue powders
with a violet shine. They are insoluble in water and
low-polarity organic solvents, readily soluble in
aqueous alkalis, and moderately soluble in DMF and
sible
complexes on electrophilic substitution [7],
bromination into the 5 position of the benzene ring to
form 5-bromo1,2,4-trimethylbenzene (II) was sub-
1070-3632/05/7506-0970 2005 Pleiades Publishing, Inc.

5-BROMOTRIMELLITIC ACID AND METAL PHTHALOCYANINES BASED THEREON
971
Me
Me
Br
KO2C
Br
Me
Me
CO2H
CO2H
Me
Me
Br2
KMnO4
I
II
III
CO2H
Br
Br
CO2H
O
N
M
N
AcONH4,
AcOH
(NH2)2CO,
metal salts
HO2C
Br
N
N
N
NH
N
N
N
O
IV
Br
CO2H
HO2C
Br
V VII
M = Co2+ (V), Cu2+ (VI), Fe2+ (VII).
DMSO. They were identified by elemental analysis
and IR and electronic absorption spectroscopy.
vibrational satellite; in going to DMF, the Q band gets
broader and shifts blue by 13 nm.
The mentioned spectral changes, as follows from
published data [12], can be related to the presence in
the solutions either of free (complexes V and VII in
1% aqueous ammonia) or associated molecules (com-
plex VI).
The IR spectra of complexes V VII contain bands
at 700 900 and 1050 1300 cm characteristic of all
1
metal phthalocyanines [11]. Like compounds III and
IV, their derived metal phthalocyanines V VIII show
in the IR spectra a band at 675 680 cm 1 from stretch-
ing vibrations of the C Br bond. The carbonyl absorp-
tion region changes radically in going from complexes
V VII to their ammonium and sodium salts. Thus,
the spectra of complexes V VII have a band at 1720
The band at
plex V in DMF should be assigned to free molecules
and that at 636 nm, to associates.
676 nm in the spectrum of com-
max
max
Comparing the electronic absorption spectra of the
complexes, we can conclude that cobalt and iron
complexes V and VII have a much weaker tendency
for association than copper complex VI. This fact can
be explained by the higher coordinating capacity of
Co2+ and Fe2+ compared with Cu2+. Compounds V
and VII in aqueous and organic media (aprotic sol-
vents) form extra complexes with solvent molecules
or hydroxide ions as extra ligands, that are arranged
axially (out of the phthalocyanine macroring plane)
and hinder intermolecular interactions.
1
1730 cm [ (C=O)], whereas it the spectra of their
ammonium salts this band is almost lacking and the
above carboxylate C=O absorption at 1370-1375 and
1
1610 1620 cm is prevailing (Fig. 1). Furthermore,
1
in the 3300 3400 cm region, there is a broad band
characteristic of ammonium N H bonds.
The electronic absorption spectra of complexes
V VII in aqueous alkalis and DMF (Fig. 2) show a
strong Q band at 600 700 nm formed by
*-elec-
tron transitions in the main conjugation contour
of the phthalocyanine macroring. The shape and posi-
tion of this band are much dependent on the nature of
the complexing metal and the solvent. Thus, the spec-
trum of complex V in 1% aqueous ammonia displays
EXPERIMENTAL
The IR spectra in KBr were measured on an Avatar-
360 FT IR spectrophotometer in the range 500
a narrow band (
682 nm) and a vibrational sa-
1
max
4000 cm . The electronic absorption spectra were
tellite (622 nm). The same complex in DMF gives a
broad band with maxima at 676 and 636 nm.
taken in DMF and 1% aqueous ammonia on a Perkin
Elmer UV Vis Lambda-200 instrument in the range
400 900 nm at 20 C for 10 5 M solutions.
The spectrum of complex VI is aqueous ammonia
and DMF contains a broad band (
647 650 nm).
5-Bromo-1,2,4-trimethylbenzene was synthesized
by the procedure in [6], mp 44 C {published data:
mp 44 C [6]}.
max
The spectrum of complex VII in aqueous ammonia
has a narrow band ( 689 nm) with an ill-defined
max
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 75 No. 6 2005

972
KULINICH et al.
(a)
2
T
1
(b)
1
3500
1500
1000
500 , cm
Fig. 1. IR spectra. (a): (1) Acid III and (2) imide IV. (b): (1) Complex V and (2) ammonium salt of complex V.
Potassium salt of 5-bromotrimellitic acid (III).
Compound II, 0.1 mol, was suspended in 400 ml of
water, the suspension was made weakly alkaline, and
heated to 70 C, after which KMnO4 was added to it
with stirring in portions of 2.5 g. When three first
portions had been added, the reaction mixture was
heated to boiling and addition of KMnO4 was con-
tinued until its crimson color no longer disappeared
(test on filter paper). Excess KMnO4 was reduced with
ethanol. The suspension was filtered while hot and
washed with hot water (2.50 ml). The filtrate and
washings were combined, pyridine was removed by
steam distillation until the distillate no longer smelled
of pyridine. The residual solution was reduced by half
and acidified to pH 4 5 with HCl. After cooling, a
precipitate formed and dried at 80 C to constant
weight to obtain 17 g (52%) of compound III as a
colorless material soluble in water and aqueous alkalis,
decomp. point 225 C. IR spectrum, , cm : 680
(CBr), 1720 (C=O in CO2H), 1611 and 1375 (CO in
CO2).
1
Imide of 5-bromotrimellitic acid (IV). Ammo-
nium acetate, 0.07 mol, was added to 10 ml of glacial
acetic acid. When the solved had dissolved completely,
0.01 mol of compound III was added. The reaction
mixture was heated under reflux for 5 h, and 5 ml of
acetic acid was distilled off. The residue was poured
into 150 ml of saturated ammonium chloride. The
precipitate that formed was filtered off, washed with
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 75 No. 6 2005

5-BROMOTRIMELLITIC ACID AND METAL PHTHALOCYANINES BASED THEREON
973
D
650
676
683
636
1.5
1.0
0.5
647
0.6
2
1
2
1
0.4
0.2
400
, nm
500
600
700
800
400
500
600
700
800
Fig. 2. Electronic absorption spectra. (a): Complex V in (1) DMF and (2) 1% aqueous ammonia. (b): Complex VI in (1) DMF
and (2) 1% aqueous ammonia.
cold water to remove chloride ions, and dried at 80
90 C to constant weight to obtain 1.1 g (44%) of
compound IV as a colorless powder, decomp. point
Br 30.5; N 10.4. C36H12Br4CoN8O8. Calculated, %: C
40.6; H 1.1; Br 30.1; N 10.5.
1
Copper(II) 2,9,16,23-tetrabromo-3,10,17,24-
tetracarboxyphthalocyanine (VI) was prepared b y
procedure b, using 1 mmol of compound IV, 8 mmol
of urea, 0.3 mol of copper(I) chloride, and a catalytic
amount of ammonium molybdate. Yield 114 mg
(43%). IR spectrum, , cm : 675 (CBr), 1720 (C=O).
Electronic absorption spectrum, max, nm: DMF 647;
H2O NH4OH (1%) 650. Found, %: C 39.9; H 1.1; Br
30.9; N 10.4. C36H12Br4CuN8O8. Calculated, %: C
40.6; H 1.1; Br 30.1; N 10.5.
290 C. IR spectrum, , cm : 680 (CBr), 1727 (C=O),
3400 3500 (NH). Found, %: C 39.7; H 1.1; Br 31.1;
N 5.4. C9H4BrNO4. Calculated, %: C 40.1; H 1.1; Br
29.7; N 5.2.
Cobalt(II) 2,9,16,23-tetrabromo-3,10,17,24-
tetracarboxyphthalocyanine (V). a. A mixture of
1 mmol of compound III, 8 mmol of urea, 0.3 mmol
of cobalt(2+) acetate, and a catalytic amount of am-
monium molybdate was melted in the following
temperature program: 140 150 C (90 min), 170
180 C (30 min), and 190 200 C (90 min). After
cooling, the melt was thoroughly ground, mixed with
15% HCl, and heated at 70 C for 30 min. The preci-
pitate was filtered off, washed with 10% HCl to color-
less crystals washings and then with water to neutral
and chloride-free washings. The solid material was
dried, washed with methanol, and dried again to ob-
tain 80 mg (30%) of compound V. IR spectrum, ,
Iron(II) 2,9,16,23-tetrabromo-3,10,17,24-tetra-
carboxyphthalocyanine (VII) was synthesized in a
similar way using 1 mmol of compound IV, 8 mmol
of urea, 0.3 mmol of iron(II) oxalate, and a catalytic
amount of ammonium molybdate. Yield 145 mg
1
(58%). IR spectrum, , cm : 675 (CBr), 1720 (C=O).
Electronic absorption spectra, max, nm: DMF: 676;
H2O NH4OH (1%) 689. Found, %: C 40.5; H 1.1; Br
30.9; N 10.4. C36H12Br4FeN8O8. Calculated, %: C
40.8; H 1.1; Br 30.2; N 10.6.
1
cm : 680 (CBr), 1720 (C=O). Found, %: C 40.7; H
1.1; Br 30.7; N 10.6. C36H12Br4CoN8O8. Calculated,
%: C 40.6; H 1.1; Br 30.1; N 10.5.
ACKNOWLEDGMENTS
b. The procedure is similar to procedure a, except
that compound IV was used as starting material in-
stead of compound III, yield 130 mg (50%). IR spec-
trum, , cm : 680 (CBr), 1720 (C=O). Electronic
absorption spectrum, max, nm: DMF: 676, 638; H2O
NH4OH (1%): 683, 622 sh. Found, %: C 40.6; H 1.2;
The work was financially supported by the Che-
mical Technologies Subprogram, Research in Higher
School in Priority Fields of Science and Technics
Program of the Ministry of Education of the Russian
Federation (project no. 203.03.02.005).
1
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 75 No. 6 2005

974
KULINICH et al.
6. Smith, L.J. and Moyle, C.L., J. Am. Chem. Soc., 1936,
REFERENCES
vol. 38, no. 1, p. 7.
1. Porfiriny: spektroskopiya, elektrokhimiya, primenenie
(Porphyrins: Spectroscopy, Electrochemistry, Applic-
ation), Enikolopyan, N.S., Ed., Moscow: Nauka, 1987.
7. Lutsenko, O.G., Kulinich, V.P., and Shaposhni-
kov, G.P., Izv. Vyssh. Uchebn. Zaved., Khim. Khim.
Tekhnol., 2003, vol. 46, no. 3, p. 107.
2. Verle, D., Girt, A., Bogdan-Rai, T., Shnurpfail, G.,
and Shopova, M., Izv. Ross. Akad. Nauk, Ser. Khim.,
1998, no. 5, p. 836.
8. Rodionov, V.M., Bogoslovskii, B.M., and Fedoro-
va, L.I., Laboratornoe rukovodstvo po khimii pro-
mezhutochnykh produktov i krasitelei (Laboratory
Manual on Chemistry of Intermediate Products and
Dyes), Moscow: Gos. Izd. Khim. Lit., 1948, p. 76.
9. Smith, A.L., Applied Infra-Red Spectroscopy, New
York: Wiley, 1979.
3. Maizlish, V.E., Shaposhnikov, G.P., Snegireva, F.P.,
Kolesnikova, E.E., and Smirnov, R.P., Izv. Vyssh.
Uchebn. Zaved., Khim. Khim. Tekhnol., 1990, vol. 33,
no. 1, p. 70.
4. Maizlish, V.E., Shaposhnikov, G.P., Snegireva, F.P.,
Kolesnikova, E.E., Velichko, A.V., and Smirnov, R.P.,
Izv. Vyssh. Uchebn. Zaved., Khim. Khim. Tekhnol.,
1992, vol. 35, no. 1, p. 37.
10. Lutsenko, O.G., Kulinich, V.P., and Shaposhni-
kov, G.P., Zh. Obshch. Khim., 2003, vol. 73, no. 9,
p. 1548.
11. Sidorov, A.N. and Kotlyar, I.P., Opt. Spektrosk., 1961,
vol. 11, no. 2, p. 175.
5. Maizlish, V.E., Shaposhnikov, G.P., Snegireva, F.P.,
Velichko, A.V., and Smirnov, R.P., RU Patent
1803409, 1993, Byull. Izobret., 1994, no. 11.
12. Rollman, L.D. and Iwamoto, R.T., J. Am. Chem. Soc.,
1968, vol. 90, no. 5, p. 1455.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 75 No. 6 2005