Cation-dependent binding of zinc diethoxycarbonylcalix[4] arenebis(porphyrinate) triethylenediamine

Article abstract of DOI:10.1134/S1070328411020059

Zinc calix[4]arene-bis(porphyrinate) with two ethoxycarbonyl substituents at the lower rim of the calix[4]arene moiety was synthesized. Its complexation properties toward the sodium cation and triethylenediamine were studied. The influence of the binding

Full text of DOI:10.1134/S1070328411020059

ISSN 1070ꢀ3284, Russian Journal of Coordination Chemistry, 2011, Vol. 37, No. 3, pp. 195–201. © Pleiades Publishing, Ltd., 2011.
Original Russian Text © G.M. Mamardashvili, N.Zh. Mamardashvili, O.I. Koifman, 2011, published in Koordinatsionnaya Khimiya, 2011, Vol. 37, No. 3, pp. 196–202.
CationꢀDependent Binding of Zinc Diethoxycarbonylcalix[4]areneꢀ
bis(porphyrinate) Triethylenediamine
G. M. Mamardashvili*, N. Zh. Mamardashvili, and O. I. Koifman
Institute of Solution Chemistry, Russian Academy of Sciences, ul. Akademicheskaya 1, Ivanovo, 153045 Russia
*Eꢀmail: gmm@iscꢀras.ru
Received April 19, 2010
Abstract—Zinc calix[4]areneꢀbis(porphyrinate) with two ethoxycarbonyl substituents at the lower rim of the
calix[4]arene moiety was synthesized. Its complexation properties toward the sodium cation and triethyleneꢀ
diamine were studied. The influence of the binding of the sodium cation by the calix[4]arene moiety on the
complexation properties of the interporphyrin cavity toward triethylenediamine was revealed.
DOI: 10.1134/S1070328411020059
Design of many artificial biomimetic systems,
which find increasing use in modern areas of science
and technology, is based on the creation of compliꢀ
cated structures with a specified arrangement of porꢀ
phyrin macrocycles and specific molecular environꢀ
ment. From this point of view, porphyrin macrocycles
functionalized by various fragments and capable of
forming complexes with both ions and neutral moleꢀ
cules are of doubtless interest. Calix[4]arenes selective
to alkaline metal cations are promising for the funcꢀ
tionalization of porphyrins by molecular fragments.
Porphyrin macrocycles in calix[4]areneporphyrins
can form the primary optical response due to chemical
reactions with substrates of a certain type [1–5].
EXPERIMENTAL
Synthesis of 5,17ꢀbis(2,8,12,18ꢀtetramethylꢀ
3,7,13,18ꢀtetraethylꢀ10ꢀphenylporphyrinyl)ꢀ25,27ꢀ
dimethoxyꢀ26,28ꢀdihydroxycalix[4]arene (H4D1).
Compound H4D1 was synthesized according to a
known procedure [5]. The UVꢀVis spectra of the comꢀ
pounds in toluene and methanol were recorded on a
1
Cary 100 spectrophotometer. The H NMR spectra
were measured on a Bruker VCꢀ500 spectrometer with
a working frequency of 500 MHz in deuterated chloꢀ
roform using tetramethylsilane as an external stanꢀ
dard. The reaction course was monitored by the results
of thin layer chromatography on Silufol UVꢀ254
plates. Individual compounds were isolated by column
chromatography on neutral alumina. Dichloꢀ
romethane–hexane (1 : 1) mixtures were used as eluꢀ
ents. Organic solvents were purified by known proceꢀ
dures [8]. The stability constants (Kst) of the calixꢀ
In this connection, the creation of porphyrinꢀconꢀ
taining macrocycle of a new type and the study of the
dependence of their properties on the composition,
structure, nature, and arrangement of molecular moiꢀ
eties seems especially urgent.
areneꢀbis(porphyrinate)
corresponding substrates (
equation
complexes
with
the
B) were determined by the
Among the most efficient calix[4]arene receptors
to sodium cations are tetraethers and tetraketones and
calix[4]arenes in the cone conformation in which the
oxygen atoms of the functional substituents at the
lower rim of the calix[4]arene macrocycle are involved
in cation binding [6, 7]. In the present work, we synꢀ
thesized zinc calix[4]areneꢀbis(porphyrinate) with
two ethoxycarbonyl substituents at the lower rim of the
calix[4]arene moiety and studied its complexation
properties toward the sodium cation and triethyleneꢀ
diamine. The influence of the interporphyrin cavity on
⎛
⎞
(
⎟
ΔAi, λ ΔAo, λ
AB
[
]
−1
1
2
(1)
,
Kst =
= 1 B
[ ]
mol l
)
⎜
A B
[ ][ ]
ΔAo, λ ΔAi, λ
⎝
⎠
1
2
where λ1 is the descending wavelength, λ2 is the
ascending wavelength, [A] is the concentration of
calixareneꢀbis(porphyrinate), [B] is the substrate conꢀ
Аo is the maximum change in the absorꢀ
bance of the solution at a given wavelength,
centration,
Δ
Δ
Аi is the
the complexation properties toward triethylenediꢀ change in the absorbance of the solution at a given
amine during sodium cation binding by the wavelength at a given concentration [9]. The calculaꢀ
calix[4]arene moiety was revealed.
tion procedure was described in detail [4, 5].
195

196
MAMARDASHVILI et al.
Synthesis of 5,17ꢀbis(2,8,12,18ꢀtetramethylꢀ
3,7,13,18ꢀtetraethylꢀ10ꢀphenylporphyrinyl)ꢀ25,27ꢀ
dimethoxyꢀ26,28ꢀdiethoxycarbonylmethylcalix[4]arene
UVꢀVis (toluene), λmax, nm (log
559 (3.79), 589 (3.39). 1H NMR (500 MHz,
CDCl3), , ppm: 9.97 (4H, s, msꢀH), 7.73 m (8H,
ε
)): 407 (4.93),
δ
(
H4D). Ethyl bromoacetate (0.02 g, 0.35 mmol) was
Ar–Hporph+calixarene), 7.35 (8H, m, Ar–Hporph+calixarene),
7.17 (4H, m, Ar–Hporph, Ar–Hcalixarene), 5.31 (4H, s,
added to a solution of H4D1 (0.30 g, 0.13 mmol) in a
dichloromethane–acetone (1 : 2) mixture (270 ml) in
the presence of K2CO3. The reaction mixture was
refluxed for 6 h, cooled, and diluted with water (1 : 1).
The organic layer was doubly washed with water,
and dichloromethane was distilled off in vacuo. The
residue was recrystallized from a dichloromethane–
methanol (1 : 2) mixture. The yield was 0.24 g
CH2Cl2), 4.06 (d, 4H,
(16H, q, CH2CH3), 3.32 (d, 4H,
J
= 13.20 Hz, ArCH2Ar), 3.89
= 13.20 Hz,
J
ArCH2Ar), 3.11 (s, 6H, OCH3), 2.92 (q, 4H,
OCH2CH3), 2.34 (24H, s, CH3), 1.29 (24H, t,
CH2CH3), 1.08 (m, 10H, OCH2CH3, –CH2–).
Zn2DꢀLint (L is triethylenediamine). 1H NMR
(88%); Rf 0.46 (Al2O3, СН2Cl2–С6Н14 (1 : 2) mixꢀ
ture as eluent).
(500 MHz, CDCl3), , ppm: 9.95 (4H, s, msꢀH), 7.70 m
δ
(8H, Ar–Hporph+calixarene), 7.31 (8H, m, Ar–Hporph+calixarene),
7.15 (4H, m, Ar–Hporph, Ar–Hcalixarene), 4.01 (d, 4H,
ArCH2Ar), 3.83 (16H, q, CH2CH3), 3.23, 4H,
ArCH2Ar), 3.10 (s, 6H, OCH3), 2.91 (q, 4H,
OCH2CH3), 2.32 (24H, s, CH3), 1.27 (24H, t,
CH2CH3), 1.05 (m, 10H, OCH2CH3, –CH2–), –3.51 s
(12H, N(CH2CH2)3N).
For C130H164N8O11
anal. calcd., %: C, 74.33;
Found, %: C, 74.29;
⋅ (CH2Cl2 + H2O)
H, 7.94;
H, 7.90;
N, 5.29.
N, 5.24.
UVꢀVis (toluene), λmax, nm (log
ε
)): 405 (5.01), 533
(4.01), 568 (3.87), 605 (3.94), 651 (3.27).
Zn2D–2Lext. 1H NMR (500 MHz, CDCl3),
,
ppm: 9.99 (4H, s, msꢀH), 7.77 m (8H, Ar–Hporph+calixarene),
7.19 (4H, m, Ar–Hporph, Ar–Hcalixarene), 4.09 (d, 4H,
= 13.20 Hz, ArCH2Ar), 3.91 (16H, q, CH2CH3),
δ
1H NMR (500 MHz, CDCl3),
, ppm: 9.92 (4H,
s, msꢀH), 7.70 m (8H, Ar–Hporph+calixarene), 7.32 (8H,
m, Ar–Hporph+calixarene), 7.14 (4H, m, Ar–Hporph
Ar–Hcalixarene), 5.30 (2H, s, CH2Cl2), 4.10 (d, 4H,
13.20 Hz, ArCH2Ar), 3.86 (16H, q, СН2СН3), 3.30 (d,
4H, = 13.20 Hz, ArCH2Ar), 3.10 (s, 6H, OCH3),
2.91 (q, 4H, ОСН2СН3), 2.32 (24H, s, CH3), 1.56 (2H,
s, H2O), 1.31 (24H, t, CH2CH3), 1.04 (m, 10H,
OCH2CH3, –CH2–), –2.18 (s, 4H, NH).
δ
,
=
J
J
3.37 (d, 4H, = 13.20 Hz, ArCH2Ar), 3.15 (s, 6H,
J
OCH3), 2.96 (q, 4H, OCH2CH3), 2.37 (24H, s, CH3),
1.32 (24H, t, CH2CH3), 1.11 (m, 10H, OCH2CH3,
CH2–), 0.09 s (6H, N(CH2CH2)3N), –2.49 s
J
⎯
(6H, N(CH2CH2)3N).
[Zn2DꢀNa+] Lint. 1H NMR (500 MHz,
CDCl3), , ppm: 9.91 (4H, s, msꢀH), 7.65 m (8H,
⎯
Synthesis of 5,17ꢀbis(zinc 2,8,12,18ꢀtetramethylꢀ
3,7,13,18ꢀtetraethylꢀ10ꢀphenylporphyrinate)ꢀ25,27ꢀ
dimethoxyꢀ26,28ꢀdiethoxycarbonylmethylcalix[4]arene
(I). Zinc acetate excess was added to a solution of
bis(porphyrin) H4D (30 mg) (mole ratio 1 : 10) in dimꢀ
ethylformamide (70 ml), and the reaction mixture was
refluxed for 30 min. The contents of the flask was
cooled, diluted with water (1 : 1), and filtered off. The
residue was dried and chromatographed on Al2O3 elutꢀ
ing with a СН2Сl2–С6Н14 (1 : 1) mixture. The solvents
were distilled off in vacuo, and the porphyrin was
recrystallized from a СН2Сl2–СН3ОН (1 : 1) mixture.
δ
Ar–Hporph+calixarene), 7.27 (8H, m, Ar–Hporph+calixarene),
7.11 (4H, m, Ar–Hporph, Ar–Hcalixarene), 4.00 (d, 4H,
ArCH2Ar), 3.83 (16H, q, CH2CH3), 3.21 (4H,
ArCH2Ar), 3.06 (s, 6H, OCH3), 2.89 (q, 4H,
OCH2CH3), 2.31 (24H, s, CH3), 1.55 (4H, s, H2O),
1.25 (24H, t, CH2CH3), 1.01 (m, 10H, OCH2CH3,
⎯
CH2–), –3.63 s (12H, N(CH2CH2)3N).
RESULTS AND DISCUSSION
The yield was 70%; Rf 0.65 (Al2O3
,
СН2Cl2–С6Н14
The reaction of H4D1 with ethyl bromoacetate in a
(1 : 2) mixture as eluent).
dichloromethane–acetone (1 : 2) mixture in the presꢀ
ence of K2CO3 affords bis(porphyrin) H4D (88%
yield), and heating of H4D with zinc acetate in dimeꢀ
thylformamide (DMFA) gave zinc bis(porphyrinate)
For C130H160N8O11Zn2
anal. calcd., %: C, 68.63;
Found, %: C, 68.59;
⋅ 2CH2Cl2
H, 7.10;
H, 7.05;
N, 4.85.
N, 4.81.
(I) (70% yield)
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 37
No. 3
2011

CATIONꢀDEPENDENT BINDING
C2H5O
197
NH
NH
H
N
N
O
O
O
N
N
HN
HN
2BrCH2COOC2H5
O
O
O
CH3COCH3, K2CO3
O
O
O
O
NH
NH
H
N
N
C2H5O
N
N
HN
HN
(H4D1)
ZnAc2
(H4D)
DMFA
C2H5O
N
N
Zn
O
O
N
N
O
O
O
O
N
N
Zn
C2H5O
N
N
(Zn2D, I)
The complex formation of calix[4]areneꢀbis(porphyrinate) I with the sodium cation follows the reaction
Zn2D + Na+
Zn2D–Na+,
(2)
N
N
Zn
N
N
Zn
N
N
N
N
O
O
O
O
O
O
O
O
(Zn2D
⎯
Na+)
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 37
No. 3
2011

198
MAMARDASHVILI et al.
(а)
(b)
Absorption
Δ
A
2.0
0.5
0.4
0.3
0.2
0.1
1.5
1.0
0.5
0
390
+
, /c
I
c
15
Na
400
410
420
0
5
10
Wavelength, nm
Fig. 1. (a) Changes in the UVꢀVis spectra in the region of the Soret band upon the reaction of compound I with NaBF in CH Cl
4 2 2
and (b) the spectrophotometric titration curves at the descending and ascending wavelengths at 25°C.
The addition of NaBF4 to bis(porphyrinate)
results in the hypsochromic shift of the Soret band in EPR spectra and stability constants.
I
type of the complexes has characteristic 1H NMR and
the UVꢀVis spectrum of the reaction mixture with the
simultaneous decrease in its intensity and broadening.
Upon the complex formation of the calix[4]arene
platform with Na+, conformational changes occur in
the macroheterocycle due to bringing together of the
tetrapyrrole moieties [10]. The results of the spectroꢀ
The studies of the present work showed that recepꢀ
and a series of earlier studied calix[4]areneꢀ
tor
I
bis(porphyrins) [4, 5, 10] form with L both “internal”
and “external” complexes, depending on the ligand
concentration. It was found in the region of the mole
ratio of the reactants receptor : substrate = 1 : (0–1)
that the spectrophotometric titration curve (Fig. 2a)
exhibited a step to which a family of isosbestic points
corresponds (Fig. 2b). The step is caused by the forꢀ
photometric titration of compound I with the sodium
cation (Fig. 1) suggest that the complex formation folꢀ
lows Eq. (2), and the stability constant of the 1 : 1
Zn2D–Na+) complex can be calculated.
mation of the 1 : 1 “internal complex (Zn2D⎯
LInt)
(
with two binding points according to the equation
The logKst value (4.30) of the complex (Zn2D–Na+
)
Zn2D + L
Zn2D–LInt.
(3)
agrees with that for the complex formed upon sodium
cation binding with tetraethoxycarbonylꢀ
a
calix[4]arene molecule of similar structure but without
tetrapyrrole macrocycles [6].
The complex formation of compound
I with a
bidentate nitrogenꢀcontaining ligand (triethylenediꢀ
amine (L)) was studied by spectrophotometric titraꢀ
tion and 1H NMR spectroscopy. Both “internal” and
“external” complexes can be formed by the reactions
of calix[4]areneꢀbis(porphyrins) with diamines [4, 5].
When 1 : 1 “internal” complexes are formed, diamine
is inserted into the interporphyrin complexꢀforming
cavity and interacts by its two nitrogen atoms with the
zinc cations of the porphyrinate moieties of the macꢀ
roheterocycle (soꢀcalled twoꢀcenter binding). The staꢀ
bility of such a complex depends on the geometric corꢀ
N
N
Zn
N
N
Zn
N
N
N
N
N
N
respondence of the cavity of the receptor (
I) to that of
the substrate (triethylenediamine). For the formation
of the 1 : 2 “external” complex, each porphyrinate
O
O
O
O
moiety of receptor I coordinates one molecule of the
ligand due to one donor–acceptor bond (oneꢀcenter
binding), whose strength depends mainly on the basicꢀ
ity of the ligand and the porphyrinate nature. Each
C2H5O
O
O
OC2H5
Zn2D–LInt
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 37
No. 3
2011

CATIONꢀDEPENDENT BINDING
199
The upfield shift of the signals from the protons of of the triethylenediamine complex with monomeric
porphyrinate of similar structure [10].
the ⎯СН2СН2– group of the ligand (Δδ = –3.51 ppm),
Under the conditions of substrate excess (from 1
to 8 moles), the spectrophotometric titration curve
exhibits the second step with a family of isosbestic
points (Fig. 2c). Probably, under these conditions,
complex formation follows Eq. (4) and affords a 1: 2
“external” complex with two binding points
their equivalence (singlet), and the ratio of intensities
of the signals from the protons of the ligand and porꢀ
phyrin moiety in the H NMR spectra of the correꢀ
1
sponding complex also indicate in favor of the formaꢀ
tion of an “internal” complex. The stability constant
of Zn2D–Lint calculated by a standard procedure [9]
using formula (1) at low concentrations of diamine
(
Zn2D–2Lext
)
Zn2D−Lint + L ꢀ Zn2D−2Lext.
(
Кst = 9.78
×
10–5 (mol/l)–1) is twofold higher than Кst
(4)
N
N
C2H5O
O
N
N
Zn
O
C2H5O
O
N
N
N
N
Zn
O
N
N
N
O
O
N
N
+
O
O
N
O
O
N
N
Zn
C2H5O
O
N
N
O
N
N
Zn
C2H5O
N
N
N
N
(Zn2D–Lint)
(Zn2D–2Lext)
The second step is characterized by the bathochroꢀ ety of bis(porphyrinate)
I
in theZn2D–2Lext complex is
10–5 (mol/l)–1, which is comparable with Kst of
1.8
×
mic shift and Soret band narrowing in the UVꢀVis
spectrum of the reaction system at the end of the proꢀ
cess compared to the spectrum of the “internal” comꢀ
plex (Fig. 2c), the downfield shift of the signals from
the protons of the porphyrin moieties of the Zn2D–2Lext
complex compared to the corresponding signals in the
spectrum of Zn2D–Lint, and splitting of the signals
from the nonequivalent protons of the alkyl fragꢀ
ments of the ligand, which appear as two signals of
different intensity. Some protons of the ligand
arranged in the immediate vicinity of the tetrapyrrole
macrocycle experience a stronger screening effect of
the 1 : 1 complex formed in the reaction of monomeric
zinc porphyrinate of analogous structure with triethylꢀ
enediamine [10].
It was found that, in the presence of sodium catꢀ
ions, the complex formation of I with L afforded only
1 : 1 “internal” complexes. One chemical equilibraꢀ
tion is established in the system at the 1 : 1 mole ratio
of the reactants (Fig. 3). Probably, conformational
changes in the calix[4]arene platform accompanied by
the approaching of the porphirinate moieties
(approaching of the reaction centers) increase the
ability of Zn2DꢀNa+ to the intracavity binding of the
ligand compared to Zn2D, and only one type of the
the
π
ꢀelectronic system and are observed in the high
field (–2.49 ppm). The protons of the ligand considꢀ
erably remote from the macrocycle experience this complex is formed at any mole ratio of the reactants
(bis(porphyrinate) : bidentate ligand)
effect to a lesser extent and appear in a weaker field
(0.09 ppm). The stability constant that characterizes
the addition of one L molecule to one porphyrin moiꢀ
+
[Zn d
2
⎯
Na+]
⎯
L.
(5)
Zn2D−Na + L ꢀ
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 37
No. 3
2011

200
MAMARDASHVILI et al.
(а)
Δ
A
0.6
0.4
0.2
c /c
L I
0
2
4
6
8
Absorption
(b)
(c)
1.0
1.0
0.5
0
0.5
0
400
410
420
430
400
410
420
430
Wavelength, nm
ꢀ6
Fig. 2. (a) Spectrophotometric titration curves of compound
I
(
c
= 8
×
10 mol/l) with substrate L in CH Cl at the descendꢀ
porph
2
2
ing and ascending wavelengths and the spectral changes upon the spectrophotometric titration of compound
I
with substrate L in
6
6
4
the region of the Soret band at
c
= (b) 0
⎯
8
×
10⎯ and (c) 8
×
10⎯ to 1
×
10⎯ mol/l at 25°C.
L
N
N
N
N
N
N
Zn
Zn
O
O
O
O
N
N
O
O
N
N
N
O
O
O
+
O
O
O
N
O
O
O
O
N
N
N
N
N
Zn
Zn
N
N
N
(Zn2D–Na+)
[Zn2D–Na+]–L
The structure of 1 : 1 [Zn2D–Na+]–L confirms the ~7 times higher than the corresponding value for the
signal from the protons of the ligand (–3.63 ppm) and “internal” complex Zn2D
Lint and ~16 times higher
Lext in
⎯
the ratio of intensities of the signals from the protons than that of the “external” complex Zn2D
⎯
of the porphyrin moiety and the ligand in the 1H NMR which each ligand is bound only to one porphyrinate
spectrum of the complex. The stability constant of moiety due to one donor–acceptor bond. Probably,
×
[Zn2D–Na+]–L is 6.31
106 (mol/l)–1, which is the binding of the sodium cation by the calix[4]arene
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 37
No. 3
2011

CATIONꢀDEPENDENT BINDING
201
Absorption
(а)
(b)
1.5
Δ
A
0.7
0.6
0.5
0.4
0.3
0.2
0.1
1.0
0.5
0
+
c /c
390
400
410
420
0
0.5
1.0
1.5
2
L I–Na
Wavelength, nm
+
Fig. 3. (a) Spectral changes in the region of the Soret band upon the reaction of complex
spectrophotometric titration curves at the descending and ascending wavelengths at 25°C.
I with Na and L in CH Cl and (b) the
2 2
moiety of complex
I
makes the interporphyrin comꢀ
REFERENCES
plexꢀforming cavity of the receptor more complemenꢀ
tary for the twoꢀcenter binding of triethylenediamine.
1. Hamilton, A., Lehn, J.M., and Sessler, J.L., J. Am.
Chem. Soc., 1986, vol. 108, no. 17, p. 5158.
Thus,
diethoxycarbonylꢀsubstituted
zinc
2. Dudic, M., Lhotak, P., Petrickova, H., et al., Tetraheꢀ
dron, 2003, vol. 59, no. 14, p. 2409.
calix[4]areneꢀbis(porphyrinate) is a variety of ionꢀ
active supramolecular devices (molecular switches).
The factor determining their functioning as switchers
is the transition of the supramolecule from one conꢀ
formation (in which the macrocycle can form stable
“internal” complexes with substrate molecules) to
another (in which the macrocycle forms no such comꢀ
plexes). The conformation and electronic and comꢀ
plexation properties of the macroheterocycle are
determined by the state of the calix[4]arene platform:
whether it exists in the free state or as a complex with
ion of a certain type.
3. Jokic, D., Asfari, Z., and Weiss, J., Org. Lett, 2002, vol.
4, no. 13, p. 2129.
4. Mamardashvili, G.M., Mamardashvili, N.Zh., and
Weiss, J., Zh. Neorg. Khim., 2005, vol. 50, no. 2, p. 258
[Russ. J. Inorg. Chem. (Engl. Transl.), vol. 50, no. 2,
p. 218].
5. Mamardashvili, G.M., Shinkar’, I.A., Mamardashꢀ
vili, N.Zh., and Koifman, O.I., Koord. Khim., 2007,
vol. 33, no. 10, p. 787 [Russ. J. Coord. Chem. (Engl.
Transl.), vol. 33, no. 10, p. 774].
6. ArnaudꢀNeu, F., Collins, E.M., Deasy, M., et al.,
ACKNOWLEDGMENTS
J. Am. Chem. Soc., 1989, vol. 111, no. 23, p. 8681.
This work was supported by the Russian Foundaꢀ
tion for Basic Research (project nos. 09ꢀ03ꢀ00040ꢀa
and 09ꢀ03ꢀ97500ꢀr_tsentr_a), the Federal Target Proꢀ
gram “Scientific and Pedagogical Specialists of Innoꢀ
vation Russia for 2009–2013” (state contract nos.
02.740.11.0106 and P 1105), and the Division of
Chemistry and Materials Science of the Russian
Academy of Sciences (program no. 1 “Theoretical and
Experimental Investigation of the Chemical Bond
Nature and Mechanisms of the Most Important
Chemical Reactions and Processes”).
7. Shinkai, S., Fujimoto, K., Otsuka, T., and Ammon, H.L.,
J. Org. Chem., 1992, vol. 57, no. 5, p. 1516.
8. Weissberger, A. and Proskauer, E.S., Organic Solvents.
Physical Properties and Methods of Purification, Ridꢀ
dick, J.A. and Toops, E.E., Eds., New York: Interꢀ
science, 1955.
9. Meites, L., An Introduction to Chemical Equilibrium and
Kinetics, Oxford: Pergamon, 1981.
10. Mamardashvili, G.M., Doctoral (Chem.) Dissertation
,
Ivanovo, 2009.
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 37
No. 3
2011