Mild template synthesis in the Cu(II)-dithiomalonamide-formaldehyde ternary system

Article abstract of DOI:10.1134/s1070363208020138

Complex formation in the ternary system Cu(II)-dithiomalonamide H ₂NC(=S)CH₂C(=S)NH₂-formaldehyde in aqueous ethanol containing copper(II) chloride, dithiomalonamide and formaldehyde, as well as in thin-layer gelatin-immobilized copper(II) hexacyanoferrate(II) matrix implants contacting with alkaline (pH > 10) aqueous solutions containing the same organic compounds was studied. In the first case, a Cu(II) bischelate complex with singly deprotonated dithiomalonamide is formed exclusively, whereas in the second case template synthesis occurs to form a macrocyclic CuL chelate (L is 1,11-diamino-1,11-disulfanyl-4,8-diaza-6-oxaundeca-1,10-diene-3,9- dithione). In the latter case, dithiomalonamide and formaldehyde function as ligsons. The above-mentioned chelate is not formed on direct contact of the reagents in aqueus ethanol both in the presence and in the absence of Cu(II). A scheme of chemical reactions that occur in the system under consideration was proposed.

Full text of DOI:10.1134/s1070363208020138

ISSN 1070-3632, Russian Journal of General Chemistry, 2008, Vol. 78, No. 2, pp. 258 263.
Pleiades Publishing, Ltd., 2008.
Original Russian Text
pp. 279 285.
O.V. Mikhailov, M.A. Kazymova, T.A. Shumilova, 2008, published in Zhurnal Obshchei Khimii, 2008, Vol. 78, No. 2,
Mild Template Synthesis
in the Cu(II) Dithiomalonamide Formaldehyde Ternary System
a
b
b
O. V. Mikhailov , M. A. Kazymova , and T. A. Shumilova
a
Kazan State Technological University,
ul. K. Marksa 68, Kazan, Tatrstan, 420015 Russia
b
Kazan State University, Kazan, Tatrstan, Russia
Received January 30, 2007
Abstract Complex formation in the ternary system Cu(II)-dithiomalonamide H NC(=S)CH C(=S)NH -
2
2
2
formaldehyde in aqueous ethanol containing copper(II) chloride, dithiomalonamide and formaldehyde, as well
as in thin-layer gelatin-immobilized copper(II) hexacyanoferrate(II) matrix implants contacting with alkaline
(pH > 10) aqueous solutions containing the same organic compounds was studied. In the first case, a Cu(II)
bischelate complex with singly deprotonated dithiomalonamide is formed exclusively, whereas in the second
case template synthesis occurs to form a macrocyclic CuL chelate (L is 1,11-diamino-1,11-disulfanyl-4,8-
diaza-6-oxaundeca-1,10-diene-3,9-dithione). In the latter case, dithiomalonamide and formaldehyde function
as ligsons. The above-mentioned chelate is not formed on direct contact of the reagents in aqueus ethanol
both in the presence and in the absence of Cu(II). A scheme of chemical reactions that occur in the system
under consideration was proposed.
DOI: 10.1134/S1070363208020138
We earlier studied [1 -5] complex formation in
ternary systems Cu(II) N,S-donor ligson mono- or
dicarbonyl ligson in gelatin-immobilized copper(II)
hexacyanoferrate(II) (Cu [Fe(CN) ]) matrix implants
Dithiomalonamide characteristically undergoes
thione thiol tautomerization, and in polar solvents the
amide exists in thione thiol form D and in the crystal
state, in thione form A.
2
6
and established the possibility of low-temperature
mild) template synthesis in these specific conditions.
S
SH
(
In all these works we used dithiooxamide H NC(=S)
NH2
2
H2N
CH
C(=S)NH as N,S-donor ligson, and as for the other
2
D
ligson we tested such carbonylcontaining compounds
as formaldehyde, ethanal, acetone, and glyoxal. These
pairs of organic reagents played the role of peculiar
building blocks for forming supramolecular metal
Dithiomalonamide, like dithiooxamide, has four
donor atoms in its structure (two sulfurs and two
nitrogens); it also belongs to ambident ligands and
can theoretically coordinate to a complexforming ion
through different donor centers. In particular, depend-
ing on the hardness of the complex-forming ion in
the HSAB hierarchy, singly deprotonated dithiomalon-
amide can bidentately coordinate in least in three
ways, through the S,S-, S,N-, and N,N-donor centers,
to form in all cases six-membered metal cycles I III,
respectively.
complexes. In principle, dithiomalonamide H NC(=S)
2
CH C(=S)NH differing from dithiooxamide in that it
2
2
has a methylene tether between the thiocarbonyl
groups, can play the role of N,S-donor ligson. Accord-
ing to X-ray diffraction data [6], dithiomalonamide in
the crystal state have conformation A; in solution,
owing to free rotation of the carbamothioyl groups
about single C C bonds, both conformation A and
conformations B and C can be realized.
H N
S
2
S
NH
S
S
S
H C
2
NH2
S
NH2
HC
HC
H N
2
S
S
NH2
S
NH2
S
CH2 S H2N
S
S
H N
2
CH2
H N
2
CH2
H N
2
A
B
C
I
II
III
258

MILD TEMPLATE SYNTHESIS
259
There are fragmentary data on complex formation
of dithiomalonamide with d-element ions [7 9], but
the information on its ability to act as ligson is com-
pletely lacking. In this connection it was important to
find whether template synthesis occurs in any ternary
system containing copper(II), dithiomalonamide, and
a carbonyl compound, for example, Cu(II)-dithio-
malonamide-formaldehyde, in aqueous ethanol and in
a gelatin-immobilized Cu [Fe(CN) ] matrix, and, if
we could isolate. It is possible to isolate a yellow-
orange substance with the brutto formula C H Cu
6
10
N S , which corresponds precisely to the [Cu(HL) ]
4
4
2
0
L
complex. Computational analysis of D = f(c , c , t)
F
kinetic curves shows that in the above range of c ,
F
0
L
c , and t, two dithiomalonamide molecules are added
per one Cu(II) ion, which is fully consistent with the
formation of such complex.
2
6
The IR spectrum of complex I contains slightly
so, to elucidate how much the resulting complexes or
other reaction products differ from each other.
1
diffuse (NH ) bands in the range 3400 3200 cm , as
2
1
well as a (NH ) band in the range of 1630 1610 cm ;
2
On exposure of a gelatin-immobilized Cu [Fe(CN) ]
the (C=S) band is shifted hypsochromically by
80 cm 1 and has a reduced intensity compared to that
of dithiomalonamide, whereas the (C N) band un-
2
6
matrix implant in an aqueous alkali solution contain-
ing dithiomalonamide and formaldehyde at dithio-
0
L
5
1
malonamide concentrations
c
<10
M, any
dergoes a bathochromic shift from 1460 cm for the
Cu [Fe(CN) ] concentration (c ) in the matrix (dithio-
free ligand to 1520 cm 1 for the complex. Such an
increase in (C N) and a decrease in (C=S) fre-
quency show that dithiomalonamide in complex I, as
expected by Pearson’s HSAB concept [12, 13], is
coordinated to Cu(II) in a bidentate fashion through
two sulfur atoms. This conclusion is also supported by
the ESR spectrum which is typical of bis-chelate
complexes with the (SSSS)-structure of the coordina-
2
6
F
malonamide-formaldehyde mole ratio 0.5 2.0), and
for a sufficiently long time (>6 min) the initially
reddish brown color of the matrix changes to grayish
blue. The electronic absorption spectra of such gelatin-
immobilized matrices contain a flat band with a
maximum at 680 700 nm in the visible region and
coincide with the spectrum of the gelatin-immobilized
polymeric hydroxide complex [Cu(OH) ] [10, 11].
tion unit (g 23, g 2.06). Consequently, the classical
2
n
||
On destruction of such matrix materials one can
isolate a grayish blue substance which, according to
its chemical analysis, is polymeric copper(II) hyd-
complex formation according to scheme (2) (metal
ion + ligand
complex) and not accompanied by any
inner-sphere conversions of the ligands occurs in the
concentration time range in question.
0
roxide. Computational analysis of D = f(c , c , t)
F
L
0
L
dependences showed that in the above range of c , c ,
F
Cu(OH) + 2H NC(=S)CH C(=S)NH
2
2
2
2
and t no addition of dithiomalonamide or formalde-
hyde takes place; instead, two OH anions are added
per one Cu(II) ion. We earlier noted the same pheno-
menon [1 5, 10, 11] in a series of binary and ternary
systems Cu(II) N,S-ligand and Cu(II) N,S-ligson
O-ligson. In this connection it is obvious that the
complex formation in the system under study is also
preceded by destruction of copper(II) hexacyanofer-
rate(II) under the action of OH anions and ac-
companied by formation of a polymeric Cu(II) hyd-
roxide [reaction (1)].
H N
2
NH2
S
S
S
CH + 2H2O
NH2
(2)
HC
Cu
S
H N
2
Treatment of the gelatin-immobilized Cu(II) hexa-
cyanoferrate(II) matrix (c 0.1 1.5 M) with aqueous
alkaline solution (pH 11 12) containing dithiomalo-
namide and formaldehyde (c 1.5 10 1.0 10 M,
dithiomalonamide formaldehyde mole ration 0.5 2.0)
results in formation, within 6 min, of compound II
that imparts a yellowish brown color to polymeric
gelatinous layer. The color change provides clear
evidence showing that complexes I and II are not
identical.
F
0
L
3
1
nCu [Fe(CN) ] + 4nOH
2
6
4
2
[Cu(OH)2]n + n[Fe(CN) ] .
(1)
6
0
L
1
At c 0.1 1.0 M, c > 1.0 10 M, t 2 10 min,
F
dithiomalonamide formaldehyde mole ratio > 2.0, and
pH 11 12, compound I is formed in the system,
which imparts a yellow color to the gelatinous layer.
Its MALDI TOF mass spectrum contains a single
molecular ion peak at m/z 330, implying formation of
only one chemical compound under these conditions.
Its spectral characteristics are close to those of the
As mentioned above, complex formation in a ge-
latin-immobilized Cu [Fe(CN) ] matrix is preceded
by alkaline destruction of copper(II) hexacyanofer-
rate(II), which is qualitatively evidenced by the fact
that the optical densities in the D = f(c , c , t) curves
2
6
0
L
F
decreases as t increases in the range 0 < t < 2 min (see
[
Cu(HL) ] complex (H L is dithiomalonamide). From
figure). Analysis of the curves for the above range of
2
2
0
gelatin-immobilized implants containing compound I
c , c , and t in various coordinate sections points to
F
L
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 78 No. 2 2008

260
MIKHAILOV et al.
(
a)
(b)
D
D
2
.0
2
.0
4
3
1
.6
1
.6
2
1
1
0
.2
.8
1
0
.2
.8
4
3
1
2
0
.4
0
0
.4
0
0.2
0.4
0.6
0.8
1.0
0
.2
0.4
0.6
0.8
1.0
c , mol dm 3
F
cF, mol dm 3
(
c)
D
2.0
4
3
2
1
1.6
1
0
.2
.8
0.4
0
0.2
0.4
0.6
0.8
1.0
cF, mol dm 3
0
0
Curves D = f(c , c , t) for the Cu(II) dithiomalonamide formaldehyde systems in coordinate sections (c are variables, c =
L
F
L
F
0
3
2
const, and t are varied) at the dithiomalonamide:formaldehyde ratio 1.00. c , M: (a) 5.0 10 , (b) 1.0 10 , and (c) 1.5
L
2
10
M at t, min: (1) 1, (2) 2, (3) 4, and (4) 10. The optical densities D were measured using a light filter with
450 nm.
max
addition of two dithiomalonamide and two formal-
dehyde molecules per one Cu(II) ion on complex
formaldehyde ternary system involves all the three
components of the system. The MALDI TOF mass
spectrum of complex II shows a single molecular ion
peak at m/z 373, implying formation of only one
chemical compound.
formation. In the absence of CH O, no compounds
2
coloring the polymeric layer in this way are formed
in a solution contacting with the matrix at any dithio-
malonamide concentration in the solution and in the
Cu [Fe(CN) ]-immobilized matrix. Therefore, the
There are three possible reasons for the specific
yellowish brown coloration of the polymeric layer of
2
6
process that occurs in the Cu(II)-dithiomalonamide-
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 78 No. 2 2008

MILD TEMPLATE SYNTHESIS
261
the immobilized matrix, produced by complex
formation:
lonamide in the absence and in the presence of form-
aldehyde are identical to each other and do not change
within at least two days at room temperature. There-
fore, the formation of this new ligand becomes pos-
sible only when Cu(II) is present in the reaction
system. In this connection there is a good reason to
think that the complex formation in the ternary system
under study involves template synthesis in the gelatin-
immobilized Cu [Fe(CN) ] matrix, as all the above-
(a) Redox reaction Cu(II) Cu(I) (since, as it is
well known, Cu(II) can oxidize dithiomalonamide
under certain conditions and convert to Cu(I) [9]);
(b) Formation of heteroligand copper(II) com-
plexes with dithiomalonamide and formaldehyde in
the inner sphere;
2
6
mentioned features are typical of such reactions
(
c) Inner-sphere conversions of dithiomalonamide
[
14, 15].
and formaldehyde, leading finally to Cu(II) complexes
with a new ligand constructed of these molecules.
Taking into account the ability of dithiomalon-
amide to coordinate in various modes, we can suggest
two possible variants of the template synthesis involv-
ing Cu(II), dithiomalonamide, and formaldehyde.
We can find out which of these variants is realized
in our case by comparing theoretically expected and
experimental data.
(
1) Formation of a Cu(II) chelate with a tetradentate
Compound II is practically insoluble in water and
in a number of organic solvents but partly soluble in
DMF and DMSO. It is paramagnetic ( eff 1.94 BM)
and gives an ESR signal at 298 K, g 2.20 and g 2.04.
N,S,S,N-donor ligand according to scheme (3).
Cu(OH) + 2H NC(=S)CH C(=S)NH + 2CH O
2
2
2
2
2
|
|
This all is typical of planar or tetragonal pyramidal
copper(II) complexes with an (NSSN) set of donor
centers coordinated to the metal. The aforesaid
suggests that Cu(II) is not reduced to Cu(I) in this
case, and, therefore, the appearance of the yellowisn
brown color is not connected with variant (a).
H N
2
NH2
S
S
HC
Cu
CH + 3H O
2
(3)
NH HN
S
S
O
There are no published data on complex formation
with formaldehyde not only for Cu(II), but also for
other d-element ions, and this circumstance casts
doubt in the possibility of variant (b) in our case.
However, even if we leave room for such possibility,
it should be expected that, if an excess of formal-
dehyde is present in the ternary system, a certain
homoligand Cu(II) complex with formaldehyde will
form. This latter complex should differ in color both
from the 1:2 homoligand Cu(II) chelate with dithio-
malonamide (yellowish orange) and from the hetero-
ligand complex. Then the color of the gelatinous layer
would change from yellowish orange to brown and
further to any other color, which actually does not
occur. All this leaves beyond question the fact that
the above-mentioned specific yellowish brown color
of the gelatinous layers cannot be connected with
formation of heteroligand metal complexes and,
hence, variant (b) should be ruled out.
(
2) Formation of a Cu(II) chelate with a tetradentate
N,N,N,N-donor ligand according to scheme (4).
Cu(OH) + 2H NC(=S)CH C(=S)NH + 2CH O
2
2
2
2
2
S
S
NH HN
(4)
H C
Cu
C2H + 3H2O
S
2
NH HN
S
O
The variant with S,S coordination of dithiomalon-
amide to Cu(II) cannot lead to template synthesis,
since cross-linking amino groups by formaldehyde
molecules is made impossible by the instability of the
resulting ten-membered cycle.
In both theoretically plausible variants, reaction
products have the same stoichiometric composition
C H CuN OS . The brown substance isolated upon
destruction of the polymer binder in gelatin-im-
mobilized matrix implants containing complex II was
found to have just this composition. Its molecular
weight (371.9) calculated with the atomic weights of
the most abundant isotopes is rather close to m/z
373 of the single peak in the MALDI TOF mass spec-
The third variant of complex formation, viz. inner-
sphere conversion of dithiomalonamide and formalde-
hyde to form a new ligand, remains the only possible
explanation. This ligand is not formed on mixing
aqueous solutions of dithiomalonamide and formal-
dehyde at room temperature, which is evidenced by
the fact that the electronic absorption spectra of
aqueous alkaline (pH >9.0) solutions of dithioma-
8
12
4
4
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 78 No. 2 2008

262
MIKHAILOV et al.
trum of complex II. This peak looks like an almost
smooth curve symmetric with respect to its maximum
and having no noticeable splitting into components.
tion. This circumstance allows us to conclude that
gelatin does not participate in complex formation as
ligand or as ligson.
The IR spectrum of complex II contains a broad
NH bending band (NH) in the region of 1620 cm 1
and a band of stretching vibrations of the bridging
Mass spectral experiments were carried out in the
MALDI TOF mode. The spectra were recorded on a
Finnigan Dynamo mass spectrometer on 4-nitrobenze-
neamine or anthracene-3-ol matrices at 298 K (work-
ing frequency 500 mHz, radiation strength 55.25 units,
accuracy of measuring peak maxima 2 units).
1
C O C group at 1080 cm . Note also the presence
1
of a (C=N) band at 1635 cm , which, by the way, is
detected neither in the spectrum of complex I nor in
the spectrum dithiomalonamide. Furthermore, in the
spectrum of complex II each of C N and C=S stretch-
The optical densities D of metal chelate gelatin-
immobilized matrixes in transmitting light were
measured on a Macbeth TD-504 photometer with the
operation range 0.1 5.0 optical density units with
a relative accuracy of 2% (rel.). The electronic ab-
sorption spectra were recorded on a Specord UV-Vis
spectrophotometer in the operation range 400 800 nm
with a relative accuracy of 2%. The IR spectra were
obtained on a UR-20 spectrometer. The pH values
were measured with a pH-150 potentiometer with an
accuracy of 0.05 pH units. The ESR spectra were
taken on a Brucker ESR200D spectrometer at 298 K.
ing bands is split into two bands (1540 and 1320 and
1
9
60 and 720 cm , respectively). This fact suggests
that at least part of sulfur and nitrogen atoms in this
compound are not coordinated to Cu(II). Such an IR
spectral pattern can only be adequately interpreted in
terms of NSSN rather than NNNN coordination of the
ligand formed by complex formation (so-called
chelant) to Cu(II). This conclusion is fully consistent
with Pearson’s HSAB concept [12, 13] and also with
our preliminary B3LYP/6-31G(d) quantum-chemical
results which show that variant 1 is more preferable
than variant 2 from the energy viewpoint. Taken to-
gether the above evidence suggests that the template
process described by Eq. (1) and giving rise to a metal
macroheterocycle, (1,11-diamino-1,11-disulfanyl-4,8-
diaza-6-oxaundeca-1,10-diene-3,9-dithione)copper(II),
actually takes place in the system in study.
Dithiomalonamide was obtained by the procedure
in [6]. Metallic potassium, 0.03 mol, was added to a
solution of 0.15 mol of malononotrile in 300 ml of
absolute isopropanol, and hydrogen sulfide was
passed through this solution under cooling ( 5 to
10 C) for 10 h. The resulting yellow precipitate was
filtered off, washed several times with a cold (2 4 C)
water, and dried in a water-jet pump vacuum. The
reaction product was twice recrystallized from water
with charcoal added and dried in a water-jet pump
vacuum. Yield 56.4 %, mp 210 C (published data
The reaction of copper(II) chloride with dithio-
malonamide and formaldehyde in a 1:2:4 ratio in
aqueous ethanol under reflux for 3 h at 70 75 C yields
a yellowish orange substance sparingly soluble in
DMF and DMSO but insoluble in water, ethanol,
benzene, chloroform, tetrachloromethane, and aceto-
nitrile. Its elemental analysis testifies that this sub-
stance has the same composition as compound I; the
same is true of the IR and ESR spectra of these two
compounds. The same result was also obtained in the
absence of formaldehyde. Thus, the complex forma-
tion in solution both in the binary system Cu(II) di-
thiomalonamide and in the ternary system Cu(II) di-
thiomalonamide formaldehyde occurs exclusively by
scheme (1), whereas template synthesis is observed
neither at room temperature nor on heating. The facts
mentioned in this paper provide evidence for a specific
role the gelatin-immobilized matrix plays as organiz-
ing system in template synthesis of nitrogen- and
sulfur-containing metal macrocycles, which has been
repeatedly noted in the literature (cf. the review [16]).
[
6]: 210 C). Found, %: C 26.6, H 4.7, N 21.0, S 47.7.
C H N S . Calculated, %: C 26,8. H 4.5, N 20.9,
3
6
2 2
S 47.8. The structure of the compound was confirmed
by IR spectroscopy.
Gelatin-immobilized Cu [Fe(CN) ] matrix implants
2
6
were obtained by the procedure in [1 4]. All reagents
for preparing matrix implants and performing complex
formation were of analytical or chemical grade and
were used as received. The resulting implants were
further treated by aqueous alkaline solutions contain-
ing dithiomalonamide and formaldehyde in (0.5 2.0):1
ratios (dithiomalonamide concentration in the solu-
tions 1.010 3 1.010 1 M), at fixed pH of 12.0 0.1
and temperature of 20.0 0.1 C. The contact times of
gelatin-immobilized Cu [Fe(CN) ] matrix materials
2
6
with solutions were 1 12 min at 20.0 0.1 C. On
completion of complex formation, the gelatinous
massif was washed with running water for 15 min and
dried for 2 3 h at room temperature. The kinetics of
EXPERIMENTAL
0
L
Special experiments showed that the brand of
gelatin has no effect on the results of complex forma-
complex formation were described by D = f(c , c ,
F
t) dependences, where D is the optical density of the
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 78 No. 2 2008

MILD TEMPLATE SYNTHESIS
263
gelatinimmobilized metal chelate matrix implant at
4. Mikhailov, O.V. and Khamitova, A.I., Koord. Khim.,
2002, vol. 28, no. 5, p. 388.
5. Mikhailov, O.V., Zh. Obshch. Khim., 2002, vol. 71,
no. 11, p. 1768.
the initial concentration (c , M) of Cu [Fe(CN) ] in
F
2
6
0
the matrix, concentration (c , M) of dithiooxamide in
L
the solution, and the reaction time (t, min). Computer
analysis of these dependences was carried out using a
modified PTKDCGIM program for treatment of kin-
etic curves of template synthesis [17], developed by
the methodology described in [18]. To determine the
total composition of metal complexes formed in
gelatin-immobilized matrix materials, the complexes
were isolated by treatment of the corresponding
matrices with solutions of proteolytic enzymes [19].
After washing and drying the isolated substances were
subjected to standard elemental analysis.
6
. Hartmurt, H., Kiel, G., and Gattow, G., Z. Natur-
forsch. B, 1981, vol. 36, no. 8, p. 1386.
. Peyronel, G., Pellacani, G.C., Benetti, G., and Pol-
lacci, G., J. Chem. Soc. Dalton Trans., 1973, no. 4,
p. 879.
7
8
9
. Pellacani, G.C., Peyronel, G., Pollacci, G., and Co-
ronati, R., J. Inorg. Nucl. Chem., 1976, vol. 38, no. 9,
p. 1619.
. Pellacani, G.C., Peyronel, G., Feltri, T., and Mena-
bue, L., Spectrochim. Acta, Part A, 1976, vol. 32,
no. 2, p. 585.
Complex I. MALDI TOF mass spectrum, m/z 330
M] . Found, %: C 21.4, H 3.1, Cu 19.5, N 16.9, S
+
10. Mikhailov, O.V. and Budnikov, G.K.., Bull. Chem.
Soc. Jpn., 1989, vol. 62, no. 12, p. 4016.
1. Mikhailov, O.V. and Polovnyak, V.K., Monatsh.
Chem., 1991, vol. 122, nos. 8/9, p. 595.
2. Pearson, R.J., J. Am. Chem. Soc., 1963, vol. 85,
no. 22, p. 3533.
[
3
1
9.0. C H CuN S . Calculated, %: C 21.8, H 3.0, Cu
9.3, N 17.0, S 38.9. Mcalc 329.9.
4 6 4 4
1
1
Complex II. MALDI TOF mass spectrum, m/z 373
M] . Found, %: C 25.6, H 3.2, Cu 16.9, N 15.2, S
+
[
3
4.0. C H CuN OS . Calculated, %: C 25.8, H 3.25,
13. Kukushkin, Yu.N., Khimiya koordinatsionnykh soedi-
nenii (Chemistry of Coordination Compounds),
Moscow: Vysshaya Shkola, 1985, p. 128.
8
12
4
4
Cu 17.1, N 15.1, O 4.3, S 34.5. Mcalc 371.9.
ACKNOWLEDGMENTS
14. Gerbeleu, N.V., Arion, V.B., and Burgess, J., Tem-
plate Synthesis of Macrocyclic Compounds, Wein-
heim: Wiley VCH, 1999.
15. Garnovskii, A.D., Vasil’chenko, I.S., and Garnov-
skii, D.A., Sovremennye aspekty sinteza metallokom-
pleksov. Osnovnye ligandy i metody (Modern Aspects
of the Synthesis of Metal Complexes. Principal
Ligands and Methods), Rostov-on-Don: LaPO, 2000.
This work was financially supported by the Russian
Foundation for Basic Research (project no. 06-03-
20003). The authors are grateful to V.I. Morozov
3
for help in measuring and interpreting the ESR spectra.
REFERENCES
1
1
1
6. Mikhailov, O.V., Rev. Inorg. Chem., 2003, vol. 23,
no. 1, p. 37.
7. Mikhailov, O.V., Khamitova, A.I., and Tsvenger, I.G.,
Available from VINITI, no. 1178-B96.
8. Mikhailov, O.V., Koord. Khim., 1992, vol. 18, no. 12,
p. 1173.
1
2
3
. Mikhailov, O.V., Trans. Met. Chem., 2000, vol. 25,
no. 5, p. 552.
. Mikhailov, O.V., Khamitova, A.I., and Morozov, V.I.,
Heterocycl. Commun., 2000, vol. 6, no. 2, p. 137.
. Mikhailov, O.V., Khamitova, A.I., and Morozov, V.I.,
19. Mikhailov, O.V., Indian J. Chem., Sect. A, 1991,
Int. J. Inorg. Mater., 2001, vol. 3, no. 2, p. 161.
vol. 30, no. 3, p. 252.
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