Synthesis and stability of bis(acetato)(5,10,15,20-tetraphenylporphyrinato) zirconium(IV)

Article abstract of DOI:10.1134/S0036023610040248

The results of studying a unique synthesis method, the kinetics and mechanism of dissociation in acid media, and the stability of a new octacoordinated zirconium complex with two bidentate acetate ligands and one 5,10,15,20-tetraphenylporphine ligand, (Ac

Full text of DOI:10.1134/S0036023610040248

ISSN 0036ꢀ0236, Russian Journal of Inorganic Chemistry, 2010, Vol. 55, No. 4, pp. 640–645. © Pleiades Publishing, Ltd., 2010.
Original Russian Text © T.N. Lomova, E.Yu. Tyulyaeva, S.E. Bachurova, 2010, published in Zhurnal Neorganicheskoi Khimii, 2010, Vol. 55, No. 4, pp. 690–695.
PHYSICAL CHEMISTRY
OF SOLUTIONS
Synthesis and Stability of Bis(acetato)(5,10,15,20ꢀ
tetraphenylporphyrinato)zirconium(IV)
T. N. Lomova, E. Yu. Tyulyaeva, and S. E. Bachurova
Institute of Solution Chemistry, Russian Academy of Sciences, ul. Akademicheskaya 1, Ivanovo, 153045 Russia
Received June 19, 2008
Abstract—The results of studying a unique synthesis method, the kinetics and mechanism of dissociation in
acid media, and the stability of a new octacoordinated zirconium complex with two bidentate acetate ligands
and one 5,10,15,20ꢀtetraphenylporphine ligand, (AcO)2ZrTPP, are presented. The method of synthesis is
distinguished by the use of stable ZrOCl2 in the complex formation reaction, instead of readily hydrolyzed zirꢀ
conium tetrachloride, in boiling phenol, which exhibits the reduction properties. The UV, visible, IR, and 1H
NMR spectral parameters and the values of chromatographic mobility and stability of the complex are
obtained. A protolytic dissociation scheme, which is universal for mixed porphyrinꢀcontaining zirconium
complexes, is substantiated using data on the dissociation rates of an (Cl)2ZrTPP analogue, depending on the
temperature and acidity of the medium. The scheme includes a trimolecular rateꢀdetermining step (the comꢀ
plex ionized at one or both noncyclic ligands and two nonionized sulfuric acid molecules) and kinetically sigꢀ
nificant equilibria of dissociation of the noncyclic acido ligands and sulfuric acid.
DOI: 10.1134/S0036023610040248
Porphyrin complexes of highly charged metal catꢀ
ions of formula (X)n – 2MP (X is the singleꢀcharge
acido ligand, and P is the porphyrin dianion) are hetꢀ
eroleptic and have high stability in solutions and in the
solid state [1, 2]. They are promising components of
materials both in the molecular form and as noncovaꢀ
lent multiporphyrin assemblies or solids, namely, catꢀ
alysts of fine macromolecular synthesis, photonics
materials (mesogens, nonlinear optical materials,
optomaterials), microporous materials, conducting
polymers, sensors, receptors in molecular recognition,
and many others [3, 4]. Therefore, the study of their
stability dependent on the nature of the central metal
cation and acido ligand is a topical problem. Data on
the synthesis and physicochemical properties of zircoꢀ
nium(IV) porphyrin compounds with various strucꢀ
tures are widely presented in the literature: (acac)2ZrP
[1], (Cl)2ZrTPP [5], Zr(OEP)2, Zr(TPP)2 [6, 7],
(AcO)2ZrOEP, and (Cl)2ZrOEP [8] (P, TPP, and OEP
are porphine, 5,10,15,20ꢀtetraphenyl21H,23Hꢀporꢀ
phine, and 2,3,7,8,12,13,17,18ꢀoctaethyl21H,23Hꢀ
porphine dianions, respectively). No quantitative data
on the stability of the complexes are given in the
aboveꢀcited works. The acetate complex with a speꢀ
cific structure of its coordination sphere was studied
only for H2OEP. Here, we studied the formation and
EXPERIMENTAL
Bis(acetato)(5,10,15,20ꢀtetraphenylporphyrinaꢀ
to)zirconium(IV), (AcO)2ZrTPP. The H2TPP and
ZrOCl2 reactants taken in a mole ratio of 1 : 5 were
refluxed at 454 K for 40 h. The reaction course was
monitored by absorption spectra of the reaction mixꢀ
ture. After the end of the reaction, the reaction mixꢀ
ture was extracted with chloroform. A solution of the
products in CHCl3 was multiply washed with warm
water to remove phenol, concentrated with partial disꢀ
tillation of the solvent, and chromatographed on a colꢀ
umn packed with Al2O3 (Brackmann activity grade II)
using chloroform. Two zones were observed: the
mobile zone of Н2ТРР (zone 1) and the zone of the
product adsorbed in the upper part of the column.
Upon the replacement of the eluent by a CHCl3 :
C2H5OH mixture (2 : 1 vol/vol), the zone separated
into a weakly pronounced mobile zone (zone 2) and an
immobile zone (zone 3) eluted only with a mixture of
5% acetic acid and ethanol. The corresponding
absorption spectra are shown in Fig. 1. The substance
of zone 3 was extracted with chloroform, and the soluꢀ
tion in chloroform was washed with water from the
acid and concentrated by evaporation. The yield of the
porphyrin complex (AcO)2ZrTPP, being in the colꢀ
umn in zone 3, was 25%.
UV–Vis (CHCl3, λmax, nm
dissociation of bis(acetato)(5,10,15,20ꢀtetrapheꢀ 500 (sh), 417 (5.23).
nylporphyrinato)zirconium(IV), hereafter
(AcO)2ZrTPP
(
logε): 539 (4.17),
IR (KBr,
ν
, cm–1): phenyl substituents: 702 (
(C–H)); 1072, 1177 ( (C–H)); 1487,
γ
.
(C=C)) 753 (
;
γ
δ
640

SYNTHESIS AND STABILITY
641
1556, 1598 (
fragments: 805 (
N), (C–H)); 1336 (
ν
(C=C)); 3054, 3059 (
(C–H)); 993, 1002 (C3–C4,
(C–N)); 1441 ( (C=N));
ν
(C–H)); pyrrole
А
4
2
γ
ν
(C–
δ
ν
ν
1540 (skeletal vibrations of pyrrole ring); coordination
core: 426 (Zr–N); 660, 725 (Zr–O); acido ligands:
1400 (νs (COO)), 1633 (νas (COO)), 2850, 2922
1
(ν
(C
1H NMR (CDCl3,
= 3 Hz), 8.00 (t, 4H,
ꢀPh, = 3 Hz), 7.75 (m, 8H,
0.86 (d, = 6 Hz), 1.73 (d, 6H, CH3COO,
For C48H34N4O4Zr anal. calcd. (%): C, 70.1; H,
4.17; N, 6.8.
Found (%):C, 69.5; H, 4.0; N, 6.1.
⎯H)).
δ
, ppm): 8.81 (t, 8H, C4H2N,
ꢀPh, = 3 Hz), 8.37 (t, 4H,
ꢀPh, 4H, ꢀPh),
= 4 Hz).
3
J
o
⎯
o
J
J
m
p
J
J
Absorption spectra were recorded on Agilent 8453
UVꢀVis, Specord Mꢀ40, and SFꢀ26 spectrophotomeꢀ
ters. IR and 1H NMR spectra were measured on Avaꢀ
tar 360 FTꢀIR ESP and Bruker (200 MHz, hexamethꢀ
yldisiloxane) spectrometers, respectively.
The kinetics of reactions of the complex in mixed
solvents containing sulfuric acid were studied by specꢀ
trophotometry. Solutions were maintained at a conꢀ
stant temperature in a special cell of the SFꢀ26 chamꢀ
ber using a U4 standard water thermostat equipped
with an external loop. The error in temperature deterꢀ
mination was 0.1 K.
Sulfuric acid of high concentrations was prepared
from H2SO4 (chemically pure grade) and sulfuric acid
monohydrate using a gravimetric method. The monoꢀ
hydrate was prepared from oleum (chemically pure
grade) and H2SO4 with potentiometric monitoring of
the concentration [9]. Glacial AcOH was obtained by
fractional unfreezing. The water content in AcOH
determined by the Fischer titration did not exceed
0.03%. Solutions of metal porphyrin in АсОН–H2SO4
mixtures of various compositions were prepared by
mixing metal porphyrin solutions having a known
concentration in glacial AcOH, a 10 M solution of
H2SO4 in glacial AcOH, and glacial AcOH.
500
600
λ
, nm
Fig. 1. Absorption spectra of (
1
2
) the compound from the
) the compound from the
second zone of the chromatogram of the products of reacꢀ
tion of H TPP with ZrOCl in a CHCl –C H OH,
reaction mixture in CHCl , (
3
2
2
3
2 5
(3) (AcO) ZrTPP in CHCl , and (4) 100% AcOH.
2 3
trile in which ZrOCl2 does not react with porphyrin.
Phenol facilitates complex formation due to the subꢀ
stitution of (OPh)2 for O2–. A similar approach was
earlier accomplished in the synthesis of osmium(II)
and ruthenium(IV) tetraphenylporphine complexes
[10].
The absorption spectrum of the compound from
the second zone contains four bands in the visible
region, as in the spectrum of H2TPP, but with another
0
The apparent rate constants,
ꢀindependent
c
H2SO4
rate constants (k), and reaction orders with respect to intensity ratio (Fig. 1, spectrum 1). A similar spectrum
0
may belong to a complex with molecular or reduced
H2TPP (the SAT complex and the complex with the
chlorin structure, respectively) [11–16]. The formaꢀ
tion of the SAT complex is a rare phenomenon in the
porphyrin chemistry and requires special conditions to
occur (a lowꢀpolarity weakly electronꢀdonating solꢀ
vent of the acetonitrile type or a partial dissociation of
the corresponding complex of the TPP2– dianion in
the solid phase). It is more probable that chlorin comꢀ
pounds will be formed during the synthesis because of
the reductive effect of phenol. Since the major product
is the ZrIV complex with the TPP2– dianion (isolated
from the third zone), the product with aforemenꢀ
(
n
)
were optimized by the least squares using
versus and log
app versus logc0H SO depenꢀ
dences, respectively. The activation energies and
c
H2SO4
ln(c0
/
c
)
τ
k
τ
2
4
≠
entropies (
E
and S ) of the reaction were determined
Δ
using the rate constants versus temperature plots.
RESULTS AND DISCUSSION
Known
zirconium
porphyrin
complexes
(Cl)2ZrTPP [5] and (Cl)2ZrOEP [8] were synthesized
using ZrCl4, which is very unstable in the presence of
trace moisture. Here, we used an original approach to
the synthesis of the zirconium complex. According to
this approach, ZrOCl2, a stable zirconium(IV) comꢀ
pound, acts as a donor of the complexing atom and the
tioned spectrum
as an impurity.
1 was not identified and was rejected
The third zone of the chromatogram contains an
reaction is carried out in phenol instead of benzoniꢀ individual compound, as was confirmed by thinꢀlayer
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 55 No. 4 2010

642
А
LOMOVA et al.
–
logkapp
3
2
2
1
3.5
4.0
2
654
533
1
0.25
0.50
1
logc
H2SO4
Fig. 3. logkapp vs. logc0H SO for the dissociation of
2
4
(AcO) ZrTPP in an AcOH–H SO mixture at
T
= (
) 323 K. The correlation coefficient (
is 0.90, 0.98, and 0.99, respectively.
1
)
)
2
2
4
313, (
2
) 318, and (
3
ρ
λ
, nm
Fig. 2. Evolution of the absorption spectrum of
(AcO) ZrTPP during the reaction in an AcOH–3M
2
were observed in addition [22]. No signals from proꢀ
tons of the phenoxy ligand coordinated on the metal
porphyrin (2.17 and 2.26 ppm in the spectrum of
(PhO)2RuTPP [11]) were observed.
H SO mixture at 313 K for
τ
= (1) 0 and (2) 3600 s. The
2
4
other lines correspond to the intermediate time moments;
–6
= 10 mol/L.
c
(AcO)2ZrTPP
Finally, it is important that the absorption specꢀ
trum of (AcO)2ZrTPP shifts toward shorter waveꢀ
lengths and a noticeable absorption appears at 460 nm
compared to the reaction product obtained before
chromatography (C2H5OH–5% АсОН, Rf = 0.5).
Based on the spectral data, the structure of the octacoꢀ
ordinated complex with two bidentate coordinated
acetate ligands (AcO)2ZrTPP (1) was ascribed to this
compound. The structure was further verified by eleꢀ
mental analysis.
chromatography (Fig. 1, lines
1 and 3). The appearꢀ
ance of the broad absorption band in the visible specꢀ
tral part near the UV region was earlier observed upon
−
the substitution of the oxo ligand for the
anion
HSO4
O
O
O
O
CH3
C
C CH3
or a molecule of organic bases [23, 24] in the
O=Mo(OH)TPP and O=W(OH)TPP complexes.
Thus, it can be concluded that the complex formation
of H2TPP with ZrOCl2 yields the oxo complex
O=ZrTPP, in which the oxo ligand is substituted by
two acetate ions on a chromatographic column in of
5% acetic acid in ethanol used for the desorption of the
third zone.
Zr
N
N
N
N
1
Since the zirconium ion has a large radius, in zircoꢀ
nium(IV) porphyrins it shifts from the macrocycle
plane by 1.01 Å on the average [17], and two
AcO⎯ acido ligands are arranged at one side from the
macrocycle. An analysis of mutual arrangement of freꢀ
quencies of symmetric and asymmetric vibrations of
O–C–O suggests the bidentate covalent binding of the
acetate ions. Indeed, the difference in the frequencies
of two vibrations is 233 cm–1, which is greater than that
(225 cm–1) for the ionic complexes and lower
(300 cm–1) for the monodentate coordination of the
carboxyl group [18–20].
The compound (AcO)2ZrTPP is stable in glacial
acetic acid at 298–373 K. The absorption spectrum in
this medium is analogous to that in an aprotic solvent
(Fig. 1; spectra 3, 4). Under analogous conditions, the
earlier studied (Cl)2ZrTPP [5] undergoes dissociation
at the M–N bonds. Upon addition of sulfuric acid
monohydrate to AcOH, 1.5–4 mol/L of (AcO)2ZrTPP
dissociates irreversibly at a measurable rate via the
overall equation
(AcO)2ZrTPP + 4H+
→
H4TPP2+ + (AcO)2Zr2+. (1)
To verify the nature of the acido ligands (–СН3) in
The H4TPP2+ ion is identified by its absorption
the compound synthesized, we carried out a comparaꢀ spectrum (Fig. 2). Reaction (1) has the first order in
ble study of its 1H NMR spectra with analogous specꢀ the metal porphyrin (Table 1). The reaction rate
tra of the earlier synthesized (Cl)2ZrTPP [5] and the increases with an increase in the initial concentration
O=ZrTPP complex, which we prepared intentionally of H2SO4 according to exponential equation (2). Relaꢀ
[21] from ZrCl4 and H2TPP in benzonitrile. In the case tionship (2) in the logarithmic coordinates (Fig. 3) is
of (AcO)2ZrTPP, signals from protons of the methyl rectilinear (
group with δ = –0.86 and 1.73 ppm in the acetate ion to the reaction order
ρ
= 0.93–0.99) with the slope ratio (equal
) close to 2 at 313 and 318 K and
n
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 55 No. 4 2010

SYNTHESIS AND STABILITY
Table 1. Apparent kinetic parameters (firstꢀorder rate constants app and activation energies
643
k
E
and entropies
Δ
S#) of the
reaction of (AcO)2ZrTPP in AcOH–H2SO4 (parameters for (Cl)2ZrTPP are given in parentheses [5]) and the reaction of
the complex in concentrated aqueous H2SO4
c0H SO
,
4
mol/L
T
, K
kapp
×
104, s–1
E
, kJ/mol
–
Δ
S#, J mol–1 K–1
2
1.5
2.0
318
298a
313
318
323
298
313
318
323
298
313
318
323
348
353
348
353
353
353
0.64 0.05
0.4 0.2 (1.41 0.01)
0.87 0.06 (0.75 0.02)
0.90 0.08 (0.25 0.01)b
1.20 0.09 (2.06 0.08)
0.16 0.03 (4 1)
1.10 0.07 (2.03 0.08)
2.00 0.05 (0.73 0.02)b
3.0 0.2 (5.69 0.02)
1.4 0.3 (13.3 0.5)
3.8 0.2 (5.7 0.25)
5.4 0.45 (2.28 0.05)b
7.40 0.06 (16.4 0.56)
0.7 0.1
27
5
245 16
(58 4)
(85.7 0.8)
3.0
4.0
113 15
(84 3)
140 45
(54 12)
56
2
139
7
(80 4)
(54 17)
16.33c
16.62c
1.10 0.05
1.1 0.1
1.00 0.06
16.95c
17.26c
1.1 0.1
1.10 0.05
a
b
c
The rate constants at 298 K were obtained by the extrapolation of the dependence of the logarithm of the constant on the inverse temperature.
Rate constant at 303 K.
Concentrated aqueous sulfuric acid.
Table 2. Kinetic parameters of the dissociation of (AcO)2ZrTPP and (Cl)2ZrTPP in AcOH–H2SO4
(AcO)2ZrTPP
105, mol–2 L2 s–1
318 K
(Cl)2ZrTPP
105 (mol–3 L3 s–1) (
313 K
k
×
(
n
)
k
×
n)
313 K
323 K
303 K
323 K
1.8 0.6
(1.99)
2.5 0.8
(2.14)
2.1 0.2*
(2.60)
0.4 0.1
(3.15)
0.9 0.1
(2.915)
2.4 0.2
(2.96)
–2.5 2.5 –1
* The dimension of the constant is mol
L
s .
to 2.5 at a higher temperature (Table 2). The following medium was not discussed. The calculated rate conꢀ
empirically determined rate equations for reaction (1) stants and reaction orders in H2SO4 are listed in
(Eqs. (3) and (4)) can be written:
Table 2. As can be seen from these data, the replaceꢀ
ment of the acido ligands in the zirconium porphyrin
complex is accompanied by an increase in the order of
0
kapp
=
k(
)n,
(2)
(3)
c
H2SO4
−dc(AcO) ZrTPP / dτ = kc
(cH0 SO )2,
2 4
reaction (2) in sulfuric acid: for (Cl)2ZrTPP, n is close
2
(AcO) ZrTPP
2
to 3. An analysis of the spectral manifestations and
kinetic laws of the dissociation reaction of both comꢀ
plexes gives the following scheme of elementary reacꢀ
tions including two rapid preꢀequilibria with the conꢀ
−dc(AcO) ZrTPP / dτ = kc
(cH0 SO
)
,
21/2
(4)
2
2
4
(AcO) ZrTPP
2
The apparent dissociation rate constants for the
(Cl)2ZrTPP complex analogous to those presented in
Table 1 were measured [5], but the dependence of the
rate on the sulfuric acid concentration in an acetic
stants Ka and
K:
+
−
H2SO4 + AcOH
↔
+
(5)
AcOH2 HSO4,
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 55 No. 4 2010

644
LOMOVA et al.
Neglect of the AcO– concentration and an approxiꢀ
(AcO)2ZrTPP+HSO4−
↔ [(HSO4)(AcO)ZrTPP]AcO−,
−
0
(6)
(7)
mate equality
[H2SO4] (see Eq. (10)) are
=
c
H2SO4
acceptable for the weak electrolyte H2SO4 in AcOH.
In this case, Eqs. (10), (11), and (12) are identical to
the rate equations of the second order (Eq. (3)), an
order of 2.5 (Eq. (4), and the third order, respectively,
experimentally derived for (Cl)2ZrTPP. The reacting
system corresponding to each of the three cases is the
dissociation of the bisacido complex (in this case,
[(HSO4)(AcO)ZrTPP]AcO + H 2SO4+H 2SO4
→ {[HSO4)(AcO)ZrH 2TPP]AcO }2+
−
+
−
+ 2HSO4 (slowly),
{[(HSO4)(AcO)ZrH 2TPP]AcO −}2+ + 2H 2SO 4
→ H 4TPP2++2HSO4− +
(8) c[(HSO )(AcO)ZrTPP]AcO− in Eq. (10) should be replaced by
4
+(HSO4)(AcO)Zr 2++AcO − (rapidly).
It is already well known [25, 26] that equilibrium
(5) becomes kinetically significant in the dissociation
reactions of metal porphyrins even at H2SO4 concenꢀ
trations higher than 0.25 mol/L and that the SE2 proꢀ
tolytic mechanism occurs in the elementary step of
dissociation of the complex with a nonplanar coordiꢀ
), the complex ionized at one acido ligand
c(AcO) ZrTPP
(
2
[(HSO4)(AcO)ZrTPP]AcO–), and the complex ionꢀ
ized at the both acido ligands ([(HSO4)2ZrTPP]2Cl–).
Thus, the kinetics of dissociation of the (X)2ZrTPP
mixedꢀligand complexes is determined by the different
states of the acido ligands depending on their nature
and temperature and the reaction rate constant
includes the ionization equilibrium constant of the
acido ligand and sulfuric acid, except for the case
where the metal porphyrin reacts as the starting neuꢀ
nation core. The SE2 mechanism is the synchronous
dissociation of two first M–N bonds under the action
of one H2SO4 molecule acting as a dibasic acid and
simultaneously protonating two N atoms. The protoꢀ
nation occurs in aqueous sulfuric acid and cannot
occur in the studied reaction of the zirconium comꢀ
plex, because in an AcOH medium H2SO4 becomes a
tral mixedꢀligand complex (X)2ZrTPP
.
The study of the stability of complex
1
in strong
acids gave the following result. In aqueous H2SO4
(AcO)2ZrTPP begins to dissolve when concentrations
exceed 14.0 mol/L. When the acid concentration
increases in the interval from 15.5 to 17.3 mol/L,
bright green color appears near the precipitate upon
the dissolution of the solid sample of the complex.
This color characteristic of the H4TPP2+ dication and
weak acid (pKa = 4.3 and 4.5 [27, 28]). Therefore,
rateꢀdetermining step (7) should be represented as a
reaction with two molecules of nonionized sulfuric
acid, whose concentration is defined by
+
[H2SO4] = cH0 SO − [AcOH2].
(9)
2
4
The kinetic equation of the rateꢀdetermining step and
the expression of concentrations in this equation
through the constants of preꢀequilibria (5) and (6) give
a rate expression for the reactions where equilibrium
(6) is ignored (shifted to the left) and where (6) is
kinetically significant:
is a qualitative test for the dissociation of metal porꢀ
phyrins [26]. The brownꢀcolored solution contains
+
ionꢀmolecular associates H TPP2+···
which is
HSolv
,
4
easily identified by the absorption spectrum consisting
of two broad bands at 540 and 690 nm in the visible
region. To verify quantitatively the dissociation of
−dc[(HSO )(AcO)ZrTPP]AcO− / dτ = −dc(AcO) ZrTPP / dτ
2
4
complex 1, we studied the kinetics of its further transꢀ
(10)
= kc[(HSO )(AcO)ZrTPP]AcO −c2
,
SO
4
formation in a sulfuric acid solution observed at temꢀ
peratures above 348 K. The final result of evolution of
the absorption spectrum in sulfuric acid is a oneꢀband
spectrum (λmax = 651 nm) in the visible corresponding
to sulfated H4TPP2+ [26]. kapp values for the reaction of
complex 1 in H2SO4 are listed in Table 1. According to
the spectral data, the apparent rate constants refer to
the sulfation of protonated porphyrin rather than to
complex dissociation, which is also indicated by the
absence of a dependence of the rates on the acidity of
the medium [30]. The kinetics of sulfation of the
Hꢀassociate of Н2ТРР was studied [30] in aqueous
solutions of H2SO4 with a concentration of 17.3–
18.1 mol/L at 338–351 K. The data obtained extend
the known range of sulfuric acid concentrations where
Н2ТРР exists as an Hꢀassociate. In our case, the assoꢀ
ciate is formed from the ligand eliminated upon the
dissociation of (AcO)2ZrTPP rather than by the dissoꢀ
lution of solid H2TPP.
H
4
2
−dc(AcO) ZrTPP / dτ = kKc(AcO) ZrTPP
c
c2
HSO4−
H SO
2
2
2
4
(11)
= kKc(AcO) ZrTPPK ac1H/2SO c2
.
2
H SO
4
2
2
4
With allowance for the weaker binding of the acido
ligands in (Cl)2ZrTPP compared to the acetato comꢀ
plex [29], equilibrium (6) should be written as
(Cl)2ZrTPP+2HSO4− ↔ [(HSO4)2ZrTPP]2Cl−,
(12)
K1
= [[(HSO4)2ZrTPP]2Cl−] / [(AcO)2ZrTPP][HSO4−]2.
Then, the rate law (Eq. (11)) for (Cl)2ZrTPP takes the
form of
−dc
/ dτ = kKc
c
c2
HSO4−
H2SO4
(Cl)2ZrTPP
(Cl)2ZrTPP
(13)
= kK1c(Cl) ZrTPPKac
c2
H SO H SO
.
2
2
4
2
4
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY Vol. 55 No. 4 2010

SYNTHESIS AND STABILITY
645
New York, 1965; Khimiya, Moscow, 1971), p. 109 [in
Russian].
10. T. N. Lomova, Advances of Porphyrin Chemistry, Ed. by
O. A. Golubchikova (S.ꢀPeterb. Gos. Univ., St. Petersꢀ
burg, 2001), Vol. 3 [in Russian].
The comparison of the stability of two zirconium
complexes (AcO)2ZrTPP and (Cl)2ZrTPP is rather difꢀ
ficult because of the different specific of the dissociaꢀ
tion mechanism (due to different dimensions of the
k
constants (Table 2)). However, the comparison of
apparent constants kapp at equal acidities of the
medium and at the same (standard) temperature
(298 K) (Table 1) indicates approximately equal staꢀ
bilities of the complexes. Reduction to the standard
temperature is important because of a complex depenꢀ
dence of the apparent activation energy of
11. E. Yu. Tyulyaeva, T. N. Lomova, and E. G. Mozhꢀ
zhukhina, Koord. Khim. 29 (8), 605 (2003).
12. J. Turay and P. Hambright, Inorg. Chem. 19, 562
(1980).
13. J. Takeda, T. Ohya, and M. Sato, Inorg. Chem. 31, 2877
(1992).
(AcO)2ZrTPP dissociation on the concentration 14. K. Tsukahara, Y. Onoue, and N. Fujiwara, J. Porphyꢀ
rins Phthalocyanines 5, 628 (2001).
cH0 SO
When the reaction order in the acid is not variꢀ
.
4
2
15. M. E. Klyueva, T. N. Lomova, B. D. Berezin, and
A. S. Semeikin, Zh. Neorg. Khim. 48 (8), 1365 (2003)
[Russ. J. Inorg. Chem. 48 (8), 1238 (2003)].
16. T. N. Lomova, E. G. Mozhzhukhina, L. P. Shorꢀ
manova, and B. D. Berezin, Zh. Obshch. Khim. 59
(10), 2317 (1989).
17. O. V. Molodkina, T. N. Lomova, and E. G. Mozhꢀ
zhukhina, Izv. Akad. Nauk, Ser. Khim., No. 10, 2052
(1998).
able ((Cl)2ZrTPP, Table 2), the E value is almost indeꢀ
pendent of the sulfuric acid concentration. Both zirꢀ
conium complexes in their stability are considerably
inferior to the (Cl)2HfTPP complex [5], which is conꢀ
sistent with the general tendency to increasing the staꢀ
bility of the complexes down columns in the Periodic
Table known for H2TPP complexes with Ni, Pd, Pt;
Cu, Ag, Au; Zr, Hf; Nb, Ta; Cr, Mo, W [1].
18. I. M. Cheremisina, Zh. Strukt. Khim. 19 (2), 336
(1978).
ACKNOWLEDGMENTS
19. T. N. Lomova and B. D. Berezin, Koord. Khim. 27 (2),
This work was supported in part by the Russian
Foundation for Basic Research, project nos. 06ꢀ03ꢀ
96343 and 07ꢀ03ꢀ00639.
96 (2001).
20. F. A. Kolokolov, Candidate’s Dissertation in Chemistry
(KGU, Krasnodar, 2003).
21. S. E. Kuskova, E. Yu. Tyulyaeva, and T. N. Lomova,
Proceedings of the 1st Regional Conference of Young Sciꢀ
entists “Theoretical and Experimental Chemistry of Liqꢀ
uid Systems”(Ivanovo, 2006), p. 21 [in Russian].
22. P. A. Stuzhin, Doctoral Dissertation in Chemistry
(IGKhTU, Ivanovo, 2004).
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