The state and stability of magnesium(II) complexes with azaporphyrins in the proton-donor medium

Article abstract of DOI:10.1134/S1070363213080136

The state and stability of magnesium complexes with various azaporphyrins in the proton-donor media containing acetic acid have been studied. Kinetic parameters of the complexes dissociation have been determined, possible reactions mechanisms have been pr

Full text of DOI:10.1134/S1070363213080136

ISSN 1070-3632, Russian Journal of General Chemistry, 2013, Vol. 83, No. 8, pp. 1548–1555. © Pleiades Publishing, Ltd., 2013.
Original Russian Text © O.G. Khelevina, M.V. Ishutkina, A.S. Malyasova, 2013, published in Zhurnal Obshchei Khimii, 2013, Vol. 83, No. 8, pp. 1318–
1325.
The State and Stability of Magnesium(II) Complexes
with Azaporphyrins in the Proton-Donor Medium
O. G. Khelevina, M. V. Ishutkina, and A. S. Malyasova
Ivanovo State University of Chemistry and Technology, Research Institute of Macroheterocyclic Compounds,
pr. F. Elgel’sa 7, Ivanovo, 153000 Russia
e-mail: helevina@yandex.ru
Received July 16, 2012
Abstract—The state and stability of magnesium complexes with various azaporphyrins in the proton-donor
media containing acetic acid have been studied. Kinetic parameters of the complexes dissociation have been
determined, possible reactions mechanisms have been proposed.
DOI: 10.1134/S1070363213080136
Chemical stabilization of azaporphyrins metal
complexes is affected by the metal ion nature, ligand
structure, nature of the proton-donor medium, and the
complex state under the conditions of the experiment.
In its complexes, magnesium forms 3s3p33d2-hybrid
coordination bonds with nitrogen coordination centers,
thus the complex is stabilized [1]. The MgN4 group is
planar. For example, the literature data [2] show that
chlorophyll is a relatively stable complex with Mg–N
coordination bonds of quite high degree of the covalent
character. Magnesium complexes of azaporphyrins are
bases containing electron donor centers (meso-nitrogen
atoms) that are capable of involvement into acid-base
interaction in a proton-donor medium, depending on
the medium acidity. The complex stability will depend
on its form, neutral or acidic, dominating under given
conditions.
We studied the ligand structure effect on the state and
stability of magnesium complexes with a series of azapor-
phyrins (Н2АР): 5,10,15,20-tetraazaporphyrin (Н2ТАР),
tetra(tetramethylene)tetraazaporphyrin (Н2ТТМТАР),
5,7-diphenyl-1,4-diazeponitribenzoporphyrazine (Н2Dz·
Bz3Pz), triazatetrabenzoporphyrin (Н2ТАТВР), and
monoazatetrabenzoporphyrin (Н2МАТВР) in the
proton-donor media containing acetic acid.
The true (or, at constant medium acidity, effective)
rate constant of the complex dissociation with the
ligand elimination was taken as a measure of the
complex stability. The complexes dissociation was fol-
lowed at different temperatures: 30, 40, 50, and 60°С.
The stability of MgTAP, MgTTMTAP, and
MgTATBP complexes was studied in the mixture of
benzene and acetic acid with addition of ethanol (4%).
N
N
N
N
M
N
N
N
C
C
N
N
N
N
N
N
N
CH2
Mg
N
N
N
N
N
N
N
N
N
Mg
N
N
N
MgTAP
MgTTMTAP
MgDzBz3Pz
1548

THE STATE AND STABILITY OF MAGNESIUM(II) COMPLEXES
–dcMgAP/dτ = kefcMgAP
1549
(2)
.
Kinetic parameters of the studied reactions cal-
culated on the basis of experimental data are collected
in Tables 1–3. As seen from the tables, the dissociation
rate constants were dependent on the acetic acid
concentration. To determine the reaction order with
respect to acetic acid, the ln kef = f[ln c(СH3СООН)]
plots were analyzed. In the benzene–acetic acid–
ethanol system at ethanol content below 4% the
equilibrium (3) was established [1], and СН3СООН
concentration was proportional to square of С2Н5ОН2+
concentration.
N
N
N
N
N
N
N
N
Mg
N
Mg
N
N
N
MgTATBP
MgMATBP
СН3СООН + С2Н5ОН ⇄С2Н5ОН2+ + СН3СОО–. (3)
The complexes dissociation occurred with the forma-
tion of the respective free ligand in the non-protonated
form.
Linear shape of the ln kef = f[ln c(СH3СООН)]
dependence suggested that the dissociation of MgTAP,
MgTTMTAP, and MgTATBP was induced by
С2Н5ОН2+, thus being a solvoprotolytic dissociation
[2]. The slope of those dependences was ~1 (Fig. 3), so
the reaction was of the second order with respect to the
solvated proton, and thus it proceeded according to the
trimolecular mechanism developed in [3].
MgAP + 2Н+ → Н2АР + Mg2+.
(1)
Figure 1 illustrates the changes of the complex
electron absorption spectrum upon dissociation,
MgTAP being a representative example. As acetic acid
was taken in large excess with respect to the complex,
the reaction was performed under conditions of the
pseudo-first order reaction. The first order with respect
to the studied complexes was confirmed by the linear
shape of the log (c0MgAP/cMgAP) = f(τ) plots (c0 and c are
initial and current concentrations of the complex,
respectively, τ is the reaction time) (Fig. 2). Thus, the
reaction was described by the first order kinetic
equation (2) with kef being the effective rate constant
of the complex dissociation.
The kinetic equation of the complexes dissociation
was as follows Eq. (4).
–dcMgAP/dτ = kvcMgAPc2(C2H5ОH2+).
(4)
The experimental data revealed that the most stable
complex was MgTATBP. Such substitution stabilized
the complex likely due to increased rigidity and
aromaticity of the macrocycle [3].
A
τ, s
λ, nm
Fig. 2. log (c0/c) as a function of time during MgТАР
complex dissociation in the benzene–acetic acid–ethanol
medium [c(СН3СООН) = 3.50 M]. (1) 303 K, (2) 313 K,
and (3) 323 K.
Fig. 1. Change in the electron absorption spectrum of
MgТАP upon complex dissociation in the benzene – acetic
acid – ethanol medium [c(СН3СООН) = 3.50 M, 323 K].
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 83 No. 8 2013

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KHELEVINA et al.
Table 1. Kinetic parameters of MgТАР dissociation in the
benzene–acetic acid–ethanol medium (c0MgТАР = 5.76×10–6 M)
Table 2. Kinetic parameters of MgТТМТАР dissociation in
the benzene–acetic acid–ethanol medium (c0MgТТМТАР
=
8.44×10–6 M)
c(CH3COOH),
kef×103,
s–1
Е,
kJ mol–1
ΔS≠,
J mol–1 K–1
Т, K
c(CH3COOH),
kef×103,
s–1
Е,
kJ mol–1
ΔS≠,
J mol–1 K–1
M
Т, K
M
0.87
1.75
2.62
3.50
4.37
298
303
313
323
298
303
313
323
298
303
313
323
298
303
313
323
298
303
313
323
0.02±0.01а
0.05±0.01
0.09±0.01
0.16±0.02
0.04±0.03а
0.11±0.03
0.21±0.02
0.40±0.01
0.07±0.03а
0.19±0.02
0.34±0.04
0.63±0.01
0.12±0.04а
0.30±0.01
0.50±0.02
0.93±0.04
0.13±0.03а
0.35±0.02
0.68±0.01
1.20±0.03
47±4
52±2
49±3
46±5
50±2
–185±6
–163±4
–168±5
–174±3
–160±6
0.87
298
303
313
323
298
303
313
323
298
303
313
323
298
303
313
323
0.11±0.02а
0.15±0.01
0.22±0.04
0.25±0.01
0.12±0.01а
0.17±0.04
0.24±0.03
0.28±0.03
0.13±0.08а
0.18±0.01
0.29±0.04
0.39±0.07
0.17±0.03а
0.29±0.06
0.40±0.05
0.55±0.07
21±6
20±5
32±4
26±2
–260±10
–261±12
–225±10
–238±9
1.045
1.31
1.485
a Calculated according to Arrhenius equation.
was revealed that the effective rate constant of
MgTTMTAP dissociation was independent of the
acetic acid concentration, and the slope of the linear
plots ln kef = f[ln c(CH3COOH)] was zero. Such result
has never been reported before.
a Calculated according to Arrhenius equation.
MgTAP was somewhat more stable than
MgTTMTAP, even though the electron donor
tetramethylene groups should have increased the
covalent character of Mg–N bonds and thus the
complex stability. There is no structural information
about Н2ТМТАР or its complexes available in the
literature; our data demonstrate that tetramethylene
groups are likely located out of the macrocycle plane
and can thus lead to the macrocycle distortion and the
Mg complex destabilization.
The mechanism of the acidoprotolytic dissociation
is as follows. In the first stage (fast) acetic acid pro-
tonated the meso-nitrogen atom. In the second stage
(slow), the intramolecular proton transfer from the
meso-nitrogen atom to the endocyclic nitrogen atom of
the MgN4 group and the rupture of one of the Mg–N
bonds occurred. The subsequent attack of СН3СООН
molecule leads to the fast rupture of the second Mg–N
and to the formation of the free ligand. СН3СОО–
anions coordinated to Mg cation.
The stability of MgTTMTAP complex was also
studied in the benzene–acetic acid medium in the
absence of ethanol. In this medium the complex
existed in the protonated form. Its dissociation
proceeded with the formation of the ligand in the non-
protonated form.
[MgTTMTAPH+]–OOCCH3
slow
[Mg+HTTMTAP]–OOCCH3 + CH3COOH
fast
The reaction was carried out in the large excess of
acetic acid, under conditions of the pseudo-first order
reaction, thus, kinetic equation (2) was applied. The
respective kinetic parameters are listed in Table 4. In
the nonpolar aprotic solvent the complex dissociation
occurred due to interaction with acetic acid molecules,
thus, it was the case of acidoprotolytic dissociation. It
H2TTMTAP + Mg(CH3COO)2.
(5)
MgTTMTAP dissociation in the benzene–acetic
acid medium was approximately twice as fast as in the
presence of ethanol, because the axial coordination of
alcohol molecules impeded the solvated proton attack
due to steric hindrance. Moreover, the complexes
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THE STATE AND STABILITY OF MAGNESIUM(II) COMPLEXES
1551
Table 3. Kinetic parameters of MgTATBP dissociation in
Table 4. Kinetic parameters of MgTTМТАP dissociation in
the benzene–acetic acid medium (c0MgТТМТАР = 8.44×10–6 M)
the benzene–acetic acid–ethanol medium (c0MgТАТВР
=
5.39×10–6 M)
c(CH3COOH),
kef×103,
s–1
Е,
kJ mol–1
ΔS≠,
J mol–1 K–1
kef×103,
s–1
Е,
kJ mol–1
ΔS≠,
J mol–1 K–1
Т, K
c(CH3COOH),
M
Т, K
0.44
0.87
1.31
1.75
298
303
313
323
298
303
313
323
298
303
313
323
298
303
313
323
0.22±0.02а
0.56±0.02
1.02±0.01
1.81±0.03
0.22±0.02а
0.56±0.03
1.10±0.02
1.92±0.03
0.22±0.02а
0.57±0.02
1.12±0.02
2.00±0.04
0.22±0.02а
0.58±0.03
1.11±0.03
2.02±0.02
48±2
50±4
50±1
50±2
–164±4
–156±6
–155±1
–157±5
M
0.87
1.31
1.75
2.185
2.62
298
313
323
333
298
313
323
333
298
313
323
333
298
313
323
333
298
313
323
333
0.15±0.01а
0.31±0.04
0.57±0.04
0.77±0.02
0.20±0.03а
0.41±0.02
0.83±0.03
1.10±0.04
0.27±0.04а
0.69±0.03
1.20±0.03
2.10±0.04
0.37±0.01а
0.87±0.02
1.50±0.05
2.40±0.04
0.59±0.02а
1.30±0.02
2.50±0.04
3.50±0.05
39±6
42±6
48±2
44±1
43±5
–254±
–202±8
–180±4
–190±3
–190±10
a Calculated according to Arrhenius equation.
The intramolecular proton transfer did not occur in
the case of MgDzBz3Pz, likely due to higher basicity
of the meso-nitrogen atoms. To support this assump-
tion, we have studied the state of Н2ТТМТАР in the
СН2Cl2–CF3COOH medium.
a Calculated according to Arrhenius equation.
protonation decreased their stability due to weakening
of the Mg–N bonds.
Figure 6 illustrates the spectral changes the during
titration of the porphyrazine dissolved in dichloro-
methane with trifluoroacetic acid, CF3COOH con-
centration being in the range of 3×10–4–1.3×10–2 M.
In the benzene–acetic acid medium, the meso-
nitrogen atom of MgDzBz3Pz was protonated [4]. The
complex dissociation in this medium was
acidoprotolytic as well, and proceeded with the formation
of the non-protonated ligand (Fig. 4). The slope of linear
plot ln kef = f[ln c(CH3COOH)] was ~1 (Fig. 5, Table 5).
Thus, in the case of MgDzBz3Pz dissociation one
molecule of acetic acid participated in the rate-limiting
stage of the reaction.
ln kef
We suggest the following scheme of MgDzBz3Pz
dissociation [Eq. (6)].
[MgDzBz3H+mesoPz]–OOCCH3
slowly
+ CH3COOH
[Mg+HDzBz3H+mesoPz](–OOCCH3)2
fast
ln c(CH3COOH)
+ CH3COOH
Fig. 3. Dependence of ln kef on ln c(CH3COOH) in the case
of MgTAP dissociation at different temperatures: (1) 298 K,
(2) 303 K, (3) 313 K, and (4) 323 K.
H2DzBz3Pz + Mg(CH3COO)2 + CH3COOH.
(6)
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KHELEVINA et al.
A
ln kef
λ, nm
Fig. 4. Change in the electron absorption spectrum of
MgDzBz3Pz upon complex dissociation, in the benzene–
acetic acid–ethanol medium [c(СН3СООН) = 3.50 M, 323 K).
(Dashed plot) shows the electron absorption spectrum of
non-protonated MgDzBz3Pz.
ln c(CH3COOH)
Fig. 5. Dependence of ln kef on ln c(СН3СООН) in the case
of MgDzBz3Pz dissociation at different temperatures: (1)
298 K, (2 ) 303 K, (3) 313 K, and (4) 323 K.
The observed red shift of Q-band in the electron
absorption spectrum of Н2ТТМТАР (624 → 643 nm
and 557 → 568 nm) was characteristic of the
protonation of meso-nitrogen atoms [5]. In order to
determine the number of CF3COOH involved in the
acid-base interaction, we analyzed the log Ii
=
f[log с(CF3COOH)] dependence (Fig. 7). The slope of
this linear plot equaled 1.74. It is known that for the
media containing trifluoroacetic acid the slope values
above 1 can be due to homoconjugation effect, when
trifluoroacetate ion is stabilized by association with
one or several acid molecules: =NH+···–OOCCF3
(HOOCCF3)n, as well as due to specific features of the
porphyrazine solvation. Thus, we could not estimate
the number of donor centers participating in the acid-
base interaction. The stability constant of acidic form
(рK) as determined by spectrophotometric titration
equaled 2.36±0.01.
Table 5. Kinetic parameters of MgDzBz3Pz dissociation in
the benzene–acetic acid medium (c0MgDzBz3Pz 7.13×10–6 M)
c(CH3COOH),
kef×103,
s–1
Е,
kJ mol–1
ΔS≠,
J mol–1 K–1
Т, K
M
0.87
1.75
2.62
3.50
4.37
298
313
323
333
298
313
323
333
298
303
313
323
298
303
313
323
298
303
313
323
0.16±0.02а
0.30±0.01
0.47±0.04
0.64±0.01
0.25±0.01а
0.53±0.04
0.66±0.03
0.86±0.03
0.33±0.08а
0.57±0.01
0.79±0.04
0.99±0.07
0.53±0.03а
0.87±0.06
1.21±0.05
1.50±0.07
0.67±0.05а
1.10±0.03
1.57±0.04
2.10±0.08
33±2
21±3
22±4
22±3
26±2
–215±10
–249±12
–230±10
–241±9
Н2DzBz3Pz protonation was studied earlier [4] and
it was shown to occur in the trifluoroacetic acid con-
centration range of 0–0.04 M in the СН2Cl2–
CF3COOH medium; рK value being 2.45±0.06.
However, in this case the diazepine nitrogen atom was
protonated, leading to monoprotonated form, [H2
{DzH+}Bz3Pz].
MgDzBz3Pz protonation occurred via the meso-
nitrogen atom in the СН2Cl2–CF3COOH medium, at
с(CF3COOH) = 0–1.3×10–2 M [4]. Thus, in the case of
Mg complex, oppositely to the case of the free ligand,
the basicity of the meso-nitrogen atoms of
porphyrazine macrocycle was higher than that of the
diazepine cycle, due to significantly ionic character of
the complex. Unfortunately, the corresponding рK
value could not be determined because its dissociation
–227±12
a Calculated according to Arrhenius equation.
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THE STATE AND STABILITY OF MAGNESIUM(II) COMPLEXES
1553
A
log I
log c(CF3COOH)
λ, nm
Fig. 6. Change in the Н2TТМТAP electron absorption
spectrum upon acid-base interaction in the dichloro-
methane–trifluoroacetic acid medium.
Fig. 7. log I = f[log c(СF3СООН)] in the case of
Н2TТМТAP acid-base interaction in the dichloromethane–
trifluoroacetic acid medium.
proceeding simultaneously with protonation. As
Н2DzBz3Pz basicity was higher than that of
Н2ТТМТАР (due to the fusion of the benzene cycles
with the macrocycle), the basicity of MgDzBz3Pz was,
correspondingly, higher than that of MgТТМТАР.
benzosubstitution of the macrocycle stabilized the
complex. In another study [8], the stability of Mg
complex with triphenylmonoazatetrabenzoporphyrin in
the benzene–acetic acid medium was investigated. It
was shown that the complex was unstable and
dissociated at с(CH3COOH) = 1.12–8.37 M. Probably,
the three phenyl groups at the periphery of the
molecule induced its distortion and thus destabilized
the complex.
MgMATBP was stable in the benzene–acetic acid
medium and occurred in the form with the protonated
meso-nitrogen atom. Fig. 8 illustrates the spectral
changes observed upon addition of acetic acid to the
benzene solution of MgМАТВР at с(CH3COOH) =
1.75×10–6–7.43×10–4 M: the decrease in the absorption
of the bands at 647 and 63, and the increase in the
absorption of the bands at 665 and 689 nm. Such shift
of the Q-band is typical of the protonation of the
porphyrazine macrocycle meso-nitrogen atom [5]. The
appeared acidic form was preserved in the pure
СН3СООН. In order to determine the number of
СН3СООН molecules participating in the acid-base interac-
tion, we analyzed the log Ii = f[log с(CH3COOH)]
dependence (Fig. 9). The slope of this linear plot was
1, which corresponded to a single donor center in
MgМАТВР molecule. The рK value of the acidic
form, as determined by means of spectrophotometric
titration, equaled +4.14±0.01. The significant basicity
of MgМАТВР was due to the substantial distortion of
the macrocycle planar structure induced by meso-
monoazasubstitution [6, 7], thus reducing the participa-
tion of the meso-nitrogen atom in the n,π-conjugation
with the macrocycle. MgМАТВР was stable in the
pure trifluoroacetic acid as well. We suggest that
Thus, MgMATBP complex was the most stable in
the benzene–acetic acid medium, despite of the
macrocycle distortion: this complex was stable under
conditions where the other complexes dissociated; the
rate constants of other complexes dissociation were of
the same order.
In [1], the macrocyclic effect was discussed as a
tool for controlling the reactivity of tetrapyrrole
macrocyclic compounds. The macrocyclic effect of
porphyrins, azaporphyrins, porphyrazines, and their
metal complexes is a phenomenon of atomic-electronic
screening of the reactive sites H2N4 and MN4. It alters
the compound reactivity via the π-electronic and struc-
tural factors. The structural part of the macrocyclic
effect is characterized by the extent of the atomic-
electronic screening of the reactive sites of the
molecule; its effect is enhanced with the increase of
aromaticity. The electronic part is determined by the
efficiency of the transmission of the effect of
peripheral groups to the reactive sites. The kinetic
stability of the Mg complexes studied in this work was
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1554
KHELEVINA et al.
A
log I
log c(CH3COOH)
λ, nm
Fig. 8. Change in the MgМАТВР electron absorption
spectrum upon acid-base interaction in the benzene –acetic
acid medium.
Fig. 9. log I = f[log c(СН3СООН)] in the case of
MgМАТВР acid-base interaction in the benzene–acetic
acid medium.
likely to be mainly due to the structural part of the
macrocyclic effect and was due to the macrocycles
aromaticity, while the effect of peripheral substituents
was not that significant.
where A0, Aτ, and A∞ are initial, current and final
solution absorbance, respectively.
For studies of acid-base interaction of MgМАТВР
and H2ТТМТАР, porphyrazines solutions of constant
concentration were prepared in media with varied
acidity, and the electronic absorption spectra were
recorded with Shimadzu UV-1800 spectrophotometer
at 298 K. The ratio of concentrations of acidic and
basic forms at equilibrium (Ii = ci/ci–1) was determined
from absorbance at wavelength corresponding to the
acidic form absorption maximum.
EXPERIMENTAL
Glacial acetic acid (chemically pure grade) was
multiply freezed out and boiled with acetic anhydride.
Then it was distilled (bp 118°С). Benzene was boiled
at reflux above P2O5 for several hours and then
distilled under atmospheric pressure, the intermediate
fraction was collected (bp 80–81°С). Ethanol was
boiled for 4 hours with calcined CaO, then CaO was
separated, and ethanol was distilled (bp 78°С).
Dichloromethane (chemically pure grade) was distilled
under atmospheric pressure above monoethanolamine
(bp 40°С).
The concentration stability constants of the
conjugate acids in the benzene–CH3COOH and
dichloromethane–CF3COOH media were calculated
according to (8).
рKi = log Ii – nlog c[CH3COOH(CF3COOH)], (8)
Azaporphyrins complexes were prepared as
described in [4, 9–11] and characterized by electron
absorption spectroscopy and by elemental analysis.
where Ii = ci/ci–1 is the ratio of ith and (i–1)th acidic
forms concentrations in equilibrium (indicator ratio); n
is the number of porphyrazine donor centers
participating in the acid-base interaction in the
respective stage.
Kinetic studies were performed in the temperature-
controlled cell of Shimadzu UV-1800 photometer at
varied temperature. The effective rate constant was
calculated from the absorbance change at wavelengths
corresponding to the bands maxima (588 nm in the
case of MgТАР, 601 nm in the case of MgTTMTAP,
675 nm in the case of MgTATBP, and 645 nm in the
case of MgDzBz3) according to Eq. (7).
MgTAP. Electron absorption spectrum (pyridine),
λ, nm (log ε): 334 (4.60), 540 (4.14), 587 (5.07).
Found, %:C 55.0; H 3.6; N 30.1. C16H8MgN8·
(СН3ОН). Calculated, %: C 55.4; H 3.3; N 30.4.
MgTТМТAP. Electron absorption spectrum
(pyridine), λ, nm (log ε): 347 (5.00), 550 (4.26), 595
kef = 2.303/τ[log (A0 – A∞)/Aτ – A∞],
(7)
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THE STATE AND STABILITY OF MAGNESIUM(II) COMPLEXES
1555
2. Berezin, B.D. and Lomova, T.N., Reaktsii dissociacii
kompleksnykh soedinenii (Reactions of Dissociation of
Complex Compounds), Moscow: Nauka, 2007.
(5.12). Found, %: C 68.9; H 6.1; N 19.0. C32H32MgN8·
(Н2О). Calculated, %: C 67.0; H 5.8; N 19.9.
MgDzBz3Pz. Electron absorption spectrum (pyri-
dine), λ, nm (log ε): 357 (4.78), 657 (4.76), 696 (4.82).
Found, %: C 69.71; H 4.08; N 18.19. C43H24MgN10·
(H2O). Calculated, %: C 69.69; H 3.81; N 18.90.
3. Berezin, B.D., Koordinatsionnaya khimiya porfirinov i
ftalocianina (Coordination Chemistry of Porphyrins and
Phthalocyanine), Moscow: Nauka, 1978.
4. Donzello, M.P., Ercolani, C., Mannina, L., Viola, E.,
Bubnova, A., Khelevina, O.G., and Stuzhin, P.A., Austr.
Chem., 2008, vol. 61, p. 262.
MgМАТВР. Electron absorption spectrum (pyri-
dine), λ, nm (log ε): 434 (5.02); 630; 644 (4.48).
Found, %:C 75.89; H 3.40; N 12.18. C35H19MgN5.
Calculated, %: C 76.16; H 3.84; N 12.18.
5. Leznoff, C.C., and Lever, A.B.P. (Eds.), Phthalo-
cyanines. Properties and Applications, New York: VCH
Publ., 1996, vol. 4.
MgTATBP. Electron absorption spectrum (pyri-
dine), λ, nm (log ε): 653; 674 (5.11). Found, %: C
70.94; H 3.34; N 17.46. C33H17MgN7. Calculated, %:
C 73.97; H 3.20; N 18.30.
6. Stuzhin, P.A., J. Porph. Phthaloc., 2003, vol.7, no. 12,
p. 813.
7. Das, J.M., and Chaudhuri, B., Acta Cryst., 1972, vol. 28,
p. 579.
ACKNOWLEDGMENTS
8. Berezin, D.B. and Shukhto, O.V., Proc. Univ. Ser.
Chem. Chem. Technol., 2003, vol. 46, no. 8, p. 34.
This work was financially supported by the
President of the Russian Federation (grant no. MK-
4171.2012.3).
9. Linstead, R.P. and Whalley, M., J. Chem. Soc., 1952,
p. 4839.
10. Brown, M., Spiera, P., and Whalley, M., J. Chem. Soc.,
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RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 83 No. 8 2013