ISSN 1070-3632, Russian Journal of General Chemistry, 2011, Vol. 81, No. 8, pp. 1691–1698. © Pleiades Publishing, Ltd., 2011. Original Russian Text © L.D. Popov, A.V. Mishchenko, Yu.P. Tupolova, S.I. Levchenkov, V.V. Minin, E.A. Ugolkova, N.N. Efimov, V.V. Lukov, I.N. Shcherbakov, V.А. Kogan, А.А. Zubenko, O.I. Askalepova, 2011, published in Zhurnal Obshchei Khimii, 2011, Vol. 81, No. 8, pp. 1346–1353.

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Synthesis, Structure, and Complexing Ability of Hetarylhydrazones of Glyoxylic Acid

L. D. Popova, A. V. Mishchenkoa, Yu. P. Tupolovaa, S. I. Levchenkovb, V. V. Mininc, E. A. Ugolkovac, N. N. Efimovc, V. V. Lukova, I. N. Shcherbakova,

V. А. Kogana, А. А. Zubenkod, and O. I. Askalepovaa a Southern Federal University, Chemical Department, ul. Zorge 7, Rostov-on-Don, 344090 Russia

e-mail: physchem@yandex.ru b Southern Scientific Center, Russian Academy of Sciences, Rostov-on-Don, Russia

e-mail: s.levchenkov@gmail.com c Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Moscow, Russia.

d North-Caucasus Regional Research Veterinary Institute, Novocherkassk Russia

Received June 17, 2010

Abstract—Benzoxazolyl-, benzthiazolyl-, 2'-quinolinyl- and 1'-phthalazinylhydrazones of glyoxylic acid (H2L) and their complexes have been synthesized. The acid–base properties of the obtained hydrazones were studied by the methods of potentiometric titration and spectrophotometry. The hydrazones were shown to form mononuclear octahedral complexes M(HL)2 with Ni(II) and Mn(II) acetates, whereas with Zn(II) and Cu(II) acetates binuclear complexes M2L2 were formed. The nature of the exchange interaction between the Cu(II) ions is discussed.

Hetarylhydrazones of carbonyl compounds are popular objects of modern organic and coordination chemistry due to their biological activity and high complexing ability [1–4]. They are reported to possess antibacterial [5–9], antiviral [10–12], antitumor [13, 14], anticon-vulsive [15] and other kinds of biological activity. A number of hetarylhydrazones are chromogenic agents, extractants, analytical sensors for metal ions [16–18]. At the same time, the data on hetarylhydrazones of aldehydo- and ketoacids are very scarce [19–21] and their coordination compounds practically have not been studied as distinct from complexes based on acylhydrazones and thioacylhydrazones [22–26].

In this work we report on the results of physico-chemical study of hetarylhydrazones of glyoxylic acid I and their transition metal complexes.

The composition and the structure of all synthesized compounds are proved by the data of elemental analysis (Table 1), IR, UV, and 1Н NMR spectroscopy (Table 2), magnetochemistry and derivatography.

The IR spectra of hydrazones Iа–Id (Table 3) show two absorption bands of the carbonyl group (С=О), the one of moderate intensity at 1690–1710 cm–1 and a highly intense band at 1650–1660 cm–1 pointing to the

DOI: 10.1134/S1070363211080184

O OH

N HNRI

R =O

N(Ia),

S

N(Ib), (Ic), (Id).

N

NN

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mp, °C Found, %

Formula Calculated, %

C H N M C H N M

Iа 221 52.5 3.51 20.6 – C9H7N3O3 52.7 3.44 20.5 –

Ib 230 48.7 3.10 18.8 – C9H7N3O2S 48.9 3.19 19.0 –

Ic 205 61.2 4.30 19.2 – C11H9N3O2 61.4 4.21 19.5 –

Id 185 55.3 3.81 26.1 – C10H8N4O2 55.6 3.73 25.9 –

IIа >250 40.6 1.76 15.9 24.1 C18H10N6O6Zn2 40.2 1.88 15.6 24.4

IIb >250 37.8 1.69 14.6 22.8 C18H10N6O4S2Zn2 38.0 1.77 14.8 23.0

IIIа >250 46.5 2.64 18.2 12.3 C18H12N6NiO6 46.3 2.59 18.0 12.6

IIIb >250 43.6 2.29 16.4 11.6 C18H12N6NiO4S2 43.3 2.42 16.3 11.8

IIIc >250 51.7 3.53 18.1 12.4 C20H16N6NiO4 51.9 3.48 18.2 12.7

IVа >250 46.3 2.69 18.3 11.5 C18H12MnN6O6 46.7 2.61 18.1 11.9

IVb >250 43.4 2.33 16.8 11.4 C18H12MnN6O4S2 43.6 2.44 17.0 11.1

IVc >250 51.9 3.49 18.2 11.8 C20H16MnN6O4 52.3 3.51 18.3 12.0

Vа >250 40.0 1.96 15.5 24.2 C18H10Cu2N6O6 40.5 1.89 15.8 23.8

Vb >250 38.5 1.69 14.6 22.9 C18H10Cu2N6O4S2 38.2 1.78 14.9 22.5

Vc >250 50.3 2.81 15.7 24.7 C22H14Cu2N6O4 50.7 2.71 16.1 24.4

Vd >250 43.5 2.26 20.0 22.7 C20H12Cu2N8O4 43.2 2.18 20.2 22.9

Comp. no.

Comp. no.

δ, ppm (DMSO-d6, 20°C)

Iа 12.6 br.s (1H, ОН), 12.2 s (1H, NН), 7.48 s (1Н, CHarom), 7.08–7.45 m (4Нarom)

Ib 12.9 br.s (1Н, ОН), 12.1 s (1Н, NН), 7.33 s (1Н, CHarom), 7.69 d (1Нarom, J 7.7 Hz), 7.49 d (1Нarom, J 8.0 Hz), 7.09–7.30 m (2Нarom)

Ic 12.19 br.s (1Н, ОН), 11.8 s (1Н, NН), 7.33 s (1Н, CHarom), 8.12 d (1Нarom, J 9.1 Hz), 7.26–7.74 m (5Нarom)

Id 13.0 br.s (1Н, ОН), 14.3 s (1Н, NН), 7.73 s (1Н, CHarom), 8.67 d (1Нphtal, Н8, J 6.0 Hz), 8.47 s (1Нphtal, Н4), 7.93–8.00 m (3Нphtal, Н5,7)

IIа 7.27 s (1Н, CHarom), 6.88–7.22 m (4Нarom)

IIb 7.13 s (1Н, CHarom), 7.57 d (1Нarom, J 7.1 Hz), 6.92–7.22 m (3Нarom)

Table 1. Elemental analysis for compounds I–V

Table 2. 1Н NMR spectra of hydrazones I in DMSO-d6, 20°C

existence of the hydrazones in different isomeric forms. In the spectrum of hydrazone Id based on hydrazinophthalazine only one absorption band of the carbonyl group is registered. The ν(NH) and ν(OH) stretching vibration bands of moderate intensity are registered at 3160 and 3430 cm–1, respectively. The absorption band of the azomethine group ν(СН=N) of

moderate intensity appears at 1610–1620 cm–1, and the ν(С=N) absorption band of the heterocyclic fragment appears at 1580–1604 cm–1.

Prototropic tautomerism is known to be charac-teristic of many heterocyclic derivatives [27–29]. In particular, in the hydrazone of hydrazinophthalazine

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Table 3. IR spectra of hydrazones I and complexes II–V

Comp. no.

ν(ОН), cm–1

ν(NH), cm–1

ν(C=O), cm–1

ν(C=N), cm–1

ν(C=N)arom, cm–1

Iа 3250 3178 1699, 1651 1613 1585

Ib 3294 3160 1694, 1656 1614 1597

Ic 3300 3190 1695, 1659 1610 1580

Id 3326 3433 1717 1620 1604

IIа – – 1630 1588 1520

IIb – – 1625 1580 1540

IIIа – 3175 1625 1586 1520

IIIb – 3160 1626 1580 1535

IIIc – 3190 1629 1589 1537

IVа – 3166 1630 1590 1540

IVb – 3187 1628 1584 1533

IVc – 3179 1627 1588 1531

Vа – – 1627 1590 1528

Vb – – 1629 1589 1526

Vc – – 1626 1588 1531

Vd – – 1625 1586 1548

the lability of the hydrogen atom is responsible for the tautomerism between the hydrazine Id and phthala-zone Id' forms:

ligands is started, most probably, with the elimination of the carboxy group proton leading to the mono-deprotonated form of the ligand. In strongly alkaline solutions of the ligands studied an elimination of the proton of the hydrazine (or heterocyclic) groups is possible.

The potentiometric titration curves for all the studied ligand systems have similar shape, therefore only one curve, namely, that for quinolinoylhydrazone of glyoxylic acid Ic, is shown in Fig. 1.

The ionization constants were calculated by Eq. (1) obtained by combined solution of the equations of material balance and electroneutrality:

HOO

NN

H NN

Id

HOO

NN

NN

Id'

H

pKai = pH + log(1 − a)cR − [H+] + [OH−]

acR + [H+] + [OH−]. (1)

According to the X-ray, electronic, IR, and NMR spectroscopy, the known hydrazones based on 1-hydrazinophthalazine exist in the free state in the phthalazone tautomeric form (in the form of mixed azines) [29–31]. The stability of the azine structure was reported to be independent of polarity of the solvent; the quantum chemical calculations are also indicative of the preference of form Id' [31–33]. The position of the band corresponding to the stretching vibrations of the NH group of the phthalazine fragment in the IR spectrum of Id points to the existence of the compound predominantly in the form of the phthala-zonehydrazone tautomer, as is the case with other hydrazones of hydrazinophthalazine; the NH proton of the hydrazine fragment is located at the heterocyclic nitrogen atom of the phthalazine fragment.

An important factor determining the complexing ability of the ligand is its protolytic properties [34–36]. The acid–base properties of hydrazones I were studied by the methods of potentiometry and UV spectroscopy. The protolytic equilibria in the solutions of hetarylhydrazones of glyoxylic acid having the azomethine and the heterocyclic nitrogen atoms capable of protonation are quantitatively characterized by the constants of ionization Kа1, Kа2, and Kа3:

Н3L+ ↔ H2L + H+ K1 = ([H+][H2L])/[H3L+],

Н2L ↔ HL– + H+ K2 = ([H+][HL–])/[H2L],

НL– ↔ L2– + H+ K3 = ([H+][L2–])/[HL–].

In acid media, apparently the azomethine nitrogen atom bearing the maximum negative effective charge and the highest density of the lone pair of electrons is first protonated. The process of ionization of the

Here (Kаi) is ith ionization constant, (а) is degree of neutralization, (cR) is total concentration of the ligand.

The values of the acid–base equilibria obtained by potentiometric titration of the studied ligand systems are presented in Table 4.

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POPOV et al. 1694

рН

V, ml

А

Wavelength, nm

Fig. 1. Potentiometric curve of the 2×10–3 M solution of compound Ic.

Fig. 2. Electron absorption spectra for the alcohol solution of compound Ib (8.84 mg l–1) at рН (1) 1.39 (λmax = 325 nm), (2) 5.77 (λmax = 310 nm), and (3) 12.61 (λmax = 370 nm).

Comp. no. pKa1 pKa2 pKa3

Iа 2.10 4.15 10.4

Ib 1.60 4.13 10.8

Ic 2.64 6.10 11.9

Id 1.80 5.13 11.2

Table 4. Ionization constants of hydrazones Ia–Id measured by potentiometric titration

We have also studied the absorption spectra of the solution of benzthyazolylhydrazone of glyoxylic acid Ib in the pH range 1.18–12.61. From the obtained experimental data (Fig. 2) the ionization constants were calculated by Eq. (2) (“+” for the 1st and 3rd series of solutions, “–” for the 2nd series): Analytical wavelengths, the absorption maxima

values, as well as the calculated pKа values for all forms of Ib are given below.

λmax, nm (Аmax, Аmin) pKa1 (R2)

pKa2 (R2) monocation (1series) neutral form (2 series) monoanion (3 series)

325 (0.995, 0.845)

310 (0.942, 0.812)

370 (0.880, 0.567)

1.89 (0.9482)

4.01 (0.9799)

11.04 (0.9978)

pKa3 (R2)

pKai = pH + log(Amax − Ai) .(Ai − Amin)

(2)

As follows from these data, the values of pKа obtained by the method of spectrophotometry are well consistent with the results of potentiometric titration.

In order to study the complexing ability of hetaryl-hydrazones of glyoxylic acid we have obtained a series of complexes of compounds Iа–Id with transition metals.

By the reaction of hetarylhydrazones Iа, Ib with zinc(II) acetate binuclear complexes II were obtained having the composition Zn2L2, where L is the doubly deprotonated form of hydrazone. The degree of deprotonation of the ligands in the complexes was proved by the 1Н NMR spectra of complexes IIа, IIb (Table 2).

In the IR spectra of complexes II the absorption bands of the OH and NH stretching vibrations are lacking; the absorption bands of the carbonyl group ν(С=О) and azomethine group ν(С=N) suffer low-frequency shift by 20–30 cm–1 relative to the starting hydrazones (Table 3). This is indicative of coordination of the metal ion with the oxygen atom of the carboxyl group and the nitrogen atoms of the azomethine and heterocyclic fragments.

No endothermic effects are observed on deri-vatograms of the complexes in the range 120–180°С,

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Comp. no.

Т, K μeff, BMa 2J, cm–1 g f

IIIа 293 77.4

3.06 2.99

IIIb 293 77.4

2.98 2.95

IIIc 293 77.4

2.96 2.95

IVа 293 77.4

5.91 5.92

IVb 293 77.4

5.89 5.91

IVc 293 77.4

5.95 5.90

Vа 293 77.4

1.57 0.98

–132 2.00 0.017

Vb 293 77.4

1.54 0.81

–159 2.00 0.024

Vc 293 77.4

1.53 0.79

–161 2.00 0.026

Vd 293 77.4

1.57 0.89

–136 2.00 0.011

NX

NN

Zn

O

O

N X

NN

Zn

O

OIIa, X = O; IIb, X = S.

IIIa, X = O; IIIb, X = S.

NX

HNN

Ni

O

O

N X

NHN

O

OIIIa, IIIb

N

HNN

O

O

IIIc

N

NHN

Ni

O

O

Table 5. Magnetic properties of complexes III–V

a μeff values are calculated per 1 metal ion.

suggesting the absence of the inner sphere molecules of the solvent in the complexes [37]; thermooxidative destruction of the ligands occurs at 280–450°С.

Realization of coordination number 4 typical for zinc(II) in this case is possible only by the formation of dimeric structure II; therewith, only the oxygen atom of the carboxylic groups can serve as bridges.

with the octahedral coordination of the central ion [38, 39]. All these data allow ascribing to the nickel complexes the octahedral structure III; the manganese complexes IV, apparently, have a similar structure.

The reaction of hydrazones Iа–Id with copper(II) acetate affords metal chelates CuL (Table 1), where L2– is the doubly deprotonated form of hydrazones.

In the IR spectra of these complexes (Table 3) the bands of stretching vibrations ν(OH) and ν(NH) are lacking, which is indicative of deprotonation of the oxygen atom of the carboxy group and the imine nitrogen atom of the hydrazone fragment. The absorp-tion bands of the stretching vibrations ν(С=О) of the carbonyl group, ν(С=N) of the azomethine and the heterocyclic fragments suffer low-frequency shift proving the tridentate character of coordination of the ligand.

The measurement of the magnetic susceptibility of complexes Vа–Vd (Table 5) has shown that for all

By the reaction of hydrazones Iа–Id with Ni(II) and Mn(II) acetates complexes III and IV, respec-tively, were obtained with the general formula [(HL)2M], where HL is the monodeprotonated form of the hydrazone.

The absence of the absorption band ν(OH) and the presence of the absorption band of the NH group of the hydrazide fragment (Table 3) suggest that the hydrazones coordinate in the monodeprotonated hyd-razone form. The spectra of the complexes also show the low-frequency shift by 20–40 cm–1 of the absorption bands of the carbonyl group ν(С=О) and the azomethine group ν(С=N) of the azomethine and heterocyclic fragments.

The values of μeff of the complexes (Table 5) lie within the ranges typical for high-spin complexes of ions Ni2+ (S = 1) and Mn2+ (S = 5/2) in the complexes

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Va, X = O; Vb, X = S.

compounds the values of µeff calculated per one copper atom at room temperature are substantially smaller than pure spin value (1.73 μB) and decrease with cooling to the temperature of liquid nitrogen. Such a pattern of the temperature dependence of magnetic susceptibility suggests the presence of exchange interaction of the antiferromagnetic type between the two copper ions and allows to ascribe the dimeric structure to metal chelates Vа–Vd.

Parameters of the exchange interaction in complexes Vа–Vd were calculated within the Heisenberg–Dirac–van Vleck model of isotropic ex-change [38, 39] using the Bleaney-Bowers equation (1). The values of exchange parameters and other model parameters are given in Table 5.

carboxy group or via the diazine chain of nitrogen atoms of the phthalazinyl fragment giving rise to the structures of the type Vd and Vd', respectively.

χ'm =2NAg2β2

3kT(1 − f) 1 + ⎯1

3exp −2J

kT

−1

+ fS(S + 1) + Nα. (3)

Here, χ'M, NA, g, β, k, J, f, and Nα are molar magnetic susceptibility corrected to diamagnetism of atoms, Avogadro’s number, Lande factor, Bohr magneton, Boltzmann constant, exchange parameter, molar fraction of paramagnetic admixture, and temperature-independent paramagnetism, respectively.

NX

NN

Cu

O

O

N X

NN

Cu

O

OVa, Vb

N

NN

Cu

O

O

N

NN

Cu

O

OVc

The type of dimerization of the complexes based on hydrazones Iа–Ic is unequivocally determined by the structure of the ligand, since the heterocyclic nitrogen atoms cannot in this case act as bridging atoms. For complex Id based on the phthalazinylhydrazone the dimerization of the mononuclear fragments of the complex can occur either via the oxygen atoms of the

N

NN

Cu

O

O

N

NN

Cu

O

OVd

N

N

N NN

N

OO

NNN

N

OO Cu

Vd'

Cu

As follows from the data of Table 5, complex Vd, as well as complexes Vа–Vc, is characterized by relatively moderate exchange coupling constant (2J = –136 cm–1). Such a value of the exchange parameter, according to the concept of geometric simulation of exchange fragments of binuclear complexes of transition metals with hydrazones developed in [40–43], is indicative of realization of a dimeric structure of the type Vd. For binuclear structure of the type Vd' the absolute value of the exchange coupling parameter should be much higher [33, 44–46].

ESR spectra of polycrystalline samples of complexes Vа–Vd contain a wide absorption band with the maximum at 1500–1700 G and an intense line at 3000–3500 G with the isotropic g-factor of 2.12–2.14. A weak band in the half-field ESR spectrum can be assigned to the “forbidden” transition in dimeric complexes of copper with the electron spin S = 1, which proves the conclusion about the dimeric structure of the complexes [47].

Therefore, the present study has shown that hetarylhydrazones of glyoxylic acid demonstrate high

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complexing ability with respect to the first-row transition metal ions, the composition and structure of the coordination compounds being determined both by the nature of the complex-forming metal and the nature of the heterocyclic fragment.

EXPERIMENTAL

1H NMR spectra were registered in DMSO-d6 on a Varian Unity 300 spectrometer (300 MHz) in Fourier pulse mode; internal reference HMDS. IR spectra were recorded on a Varian Scimitar 1000 FT-IR instrument in the range 400–4000 cm–1 from suspensions in mineral oil or in oil of fluorinated hydrocarbons. ESR spectra were registered on a Е-680Х ELEXSYS “Bruker” radiospectrometer in the Х-range at room temperature and the temperature of liquid nitrogen. Thermal analysis of complexes was performed with the use of Diamond TG/DTA instrument (Perkin Elmer). The samples were heated to 650°С at the rate 10 deg min–1.

Protolytic properties of the studied ligand systems were investigated by potentiometric titration and spectrophotometry. pH Values were determined on a I-120М ionomer. The solutions for potentiometric titra-tion were prepared by dissolution of precisely weighed specimen (0.1 mmol) of ligands Iа–Id in water–alcohol mixture (1:1) with addition of 0.2 mmol of НСl for compounds Iа–Ic and 0.3 mmol for Id. The samples were titrated with 0.1 М solution of NaOH at 25°С and constant ionic power I = 0.1 (KСl). Electron absorp-tion spectra were taken on a Varian Cary 50 Scan spectrophotometer. Three series of solutions (corres-ponding to three dissociation constants) were prepared, with the following pH values: 1 series: 1.18, 1.39, 1.74, 1.94, 2.43, 2.80; 2 series: 4.02, 4.40, 4.98, 5.31, 5.77, 6.34, 7.02; 3 series: 10.52, 10.93, 11.37, 11.82, 12.23, 12.61. 25 ml volumetric flasks were charged with 5 ml of alcohol solution of the studied ligand (c = 2×10–4

M), 7.5 ml of ethyl alcohol, and filled to 25 ml with water solution of acid or alkali (1 and 0.1 М solutions of NaOH and HCl were used) with the pre-measured value of рH, and thoroughly stirred. Then, the control measurement of pH was performed and the light absorption was determined for the solutions of the 1 series at λmax = 325 nm, 2 series, at λmax = 310 nm, and 3 series, at λmax = 370 nm.

The specific magnetic susceptibilities of the complexes were determined by the Faraday’s relative technique in the range of 77.4–300 K, using

Hg[Co(CNS)4] as the reference compound for calibration. The theoretical interpretation of the temperature dependence of magnetic susceptibility of binuclear complexes was performed within the Heisenberg–Dirac–van Vleck model of isotropic exchange [31, 32].

Synthesis of hydrazones Iа–Id. To the suspension of 0.9 mmol of the appropriate hydrazine in 10 ml H2O 3 drops of conc. HCl was added, stirred at room temperature for 5 min, filtered through a paper filter, the solution of 1 mmol of glyoxylic acid in 2 ml H2O was added, the mixture was stirred for 4 h; the formed precipitate was filtered off, washed with water and crystallized from ethanol.

Synthesis of complexes II–V. To a hot suspension or solution of 1 mmol of hydrazone I in methanol a hot solution of the metal salt in methanol (1 mmol) was added, refluxed for 1–4 h, the precipitate formed was filtered off and washed several times with hot methanol, and dried in a vacuum at room temperature.

ACKNOWLEDGMENTS

This work was performed under a financial support of the Federal Target Program “Academic and teaching staff of innovative Russia” (project no. 02.740.11.0255) and grant no. 10-03-91171 GFEN.

REFERENCES

1. Kitaev, Yu.P. and Buzykin, B.N., Hydrazones, Moscow: Nauka, 1974. 2. Troepol’skaya, T.V. and Munin, E.N., Chemistry of Hydrazones, Moscow: Nauka, 1977. 3. Shchegol’kov, E.V., Burgart, Ya., V., Khidina, O.G., Saloutin, V.I., and Chupakhin, O.N., Russ. Chem. Rev. Engl. Transl., 2010, vol. 79, no. 1, p. 31. 4. Popov, L.D., Morozov, A.N., Shcherbakov, I.N., Tupolova, Yu.P., Lukov, V.V., and Kogan, V.А., Russ. Chem. Rev. Engl. Transl., 2009, vol. 78, no. 7, p. 643. 5. Hakki, E., Safak, C., Mevlut, E., and Nuran, Y., J. Indian Chem. Soc., 1989, vol. 66, no. 1, p. 45. 6. Mishra, P., Gupta, P.N., and Shakya, A.K., J. Indian Chem. Soc., 1991, vol. 68, no. 11, p. 618. 7. Likhate, M.A. and Fernandes, P.S., J. Indian Chem. Soc., 1990, vol. 67, no. 10, p. 862. 8. Badr, M.Z.A., Mahmoud, M.A., Mahgoub, S.A., and Hoziem, Z.A., Bull. Pol. Acad. Sсi. Chem., 1989, vol. 37, no. 5-6, p. 185. 9. Revankar, V.K., Arali, V.H., and Mehale, V.B., Indian. J. Chem. A, 1990, vol. 29, no. 9, p. 889.

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10. Bartolucci, C., Cellai, L., Patrizia, F., Brizzi, V., Pollrano, C., Savani, L., Arrigo, B., and Guiliano, E., Farmaco, 1992, vol. 41, no. 5, p. 945. 11. Vicini, P., Incerti, M., Doychinova, I.A., LaColla, P., Busonera, B., and Loddo, R., Eur. J. Med. Chem., 2006, vol. 41, no. 5, p. 624. 12. Srivastawa, N. and Misra, V.S., Indian. J. Chem. B, 1988, vol. 27, no. 3, p. 298. 13. Pellerano, C., Savini, L., and Massarelli, P., Farmaco Ed. Sci., 1985, vol. 40, no. 9, p. 645. 14. Jain, R., Dixit, A., J. Indian Chem. Soc., 1990, vol. 67, no. 2, p. 179. 15. Popp, F.D., Eur. J. Med. Chem., 1989, vol. 24, no. 3, p. 313. 16. Odashima, T., Yamaguchi, M., and Ishii, H., Micro- chim. Acta, 1991, vol. 1, nos. 5–6, p. 267. 17. Sakamoto, H., Ishikawa, J., Nakagamo, H., Ito, X., Ogawa, K., Doi, K., and Otono, M., Chem. Lett., vol. 21, 1992, no. 3, p. 481. 18. Katyal, M. and Dutt, Y., Talanta, 1975, vol. 22, no. 2, p. 151. 19. Khattab, S.N., Hassan, S.Y., El-Faham, A., El Mas- sry, A.M.M., and Amer, A., J. Heterocycl. Chem., 2007, vol. 44, no. 3, p. 617. 20. Sawhaney, S.N., Bhutani, S., and Dharam, V., Indian. J. Chem. B, 1987, vol. 26, no. 4, p. 348. 21. Katyal, M., Kundra, S.K., Goel, D.P., and Singh, R.P., J. Indian Chem. Soc., 1974, vol. L1, no. 5, p. 576. 22. Ferrari, M.B., Bisceglie, F., Fava, G.G., Pelosi, G., Tarasconi, P., Albertini, R., and Pinelli, S., J. Inorg. Biochem., 2002, vol. 89, nos. 1–2, p. 36. 23. Dodoff, N.I., Kovala-Demertzi, D., Kuduk-Jaworska, J., Kubiak, M., and Kochel, A., Cryst. Res. Technol., 2007, vol. 42, no. 5, p. 517. 24. Yin, H.D., Hong, M., Wang, Q.B., Xue, S.C., and Wang, D.Q., J. Organomet. Chem., 2005, vol. 690, no. 6, p. 1669. 25. Lu, W.-G., Liu, H.-W., Feng, X.-L., and Chin., J., Inorg. Chem., 2004, vol. 20, no. 3, p. 313. 26. Yin, H., Hong, M., Xu, H., Gao, Z., Li, G., and Wang, D., Eur. J. Inorg. Chem., 2005, no. 22, p. 4572. 27. Katritzky, A.R., Karelson, M., and Harris, P.A., Heterocycles, 1991, vol. 32, no. 2, p. 329. 28. Paolucci, G., Stelluto, S., Sitran, S., Ajo, D., Benetollo, F., Polo, A., and Bombieri, G., Inorg. Chim. Acta, 1992, vol. 193, no. 1, p. 57. 29. Giorgi, G., Ponticelli, F., Savini, L., Chiasserini, L., and Pellerano, C., J. Chem. Soc., Perkin Trans. 2, 2000, p. 2259. 30. Bystrykh, N.N., Buzykin, B.I., Stolyarov, A.P., Flegontov, S.A., and Kitaev, Yu.P., Chem. Heterocycl. Comp., 1981, vol. 17, no. 5, p. 678.

31. Kogan, V.A., Levchenkov, S.I., Popov, L.D., and Shcherbakov, I.N., Ross. Khim. Zh., 2009, vol. 53, no. 1, p. 86. 32. Shcherbakov, I.N., Popov, L.D., Levchenkov, S.I., Morozov, A.N., Kogan, V.A., and Vikrishchuk, A.D., Russ. J. Gen. Chem., 2009, vol. 79, no. 4, p. 826. 33. Popov, L.D., Levchenkov, S.I., Shcherbakov, I.N., Kogan, V.A., Tupolova, Yu.P., Russ. J. Gen. Chem., 2010, vol. 80, no. 3, p. 493. 34. Shoukry, A.A. and Shoukry, M.M., Spectrochim. Acta, A., 2008, vol. 70, no. 3, p. 686. 35. Popov, L.D., Askalepova, O.I., Levchenkov, S.I., and Kogan, V.A., Russ. J. Inorg. Chem., 2007, vol. 52, no. 4, p. 626. 36. Popov, L.D., Levchenkov, S.I., Shcherbakov, I.N., and Kogan, V.A., Russ. J. Gen. Chem., 2007, vol. 77, no. 7, p. 1284. 37. Kukushkin, Yu.N., Khodzhaev, O.F., Budanova, V.F., and Parpiev, N.A., Termoliz koordinatsionnykh soedinenii (Thermolisys of Coordinated Compounds). Tashkent: Fan, 1986. 38. Kalinnikov, V.T. and Rakitin, Yu.V., Vvedenie v magnetokhimiyu (Introduction to Magnetochemistry), Мoscow: Nauka, 1980.. 39. Rakitin, Yu.V. and Kalinnikov, V.T., Sovremennaja magnetokhimija (Modern Magnetochemistry), St. Petersburg: Nauka, 1994. 40. Kogan, V.A. and Lukov, V.V., Koord. Khim., 1993, vol. 19, no. 6, p. 476. 41. Kogan, V.A. and Lukov, V.V., Russ. J. Coord. Chem., 1997, vol. 23, no. 1, p. 16. 42. Kogan, V.A., Lukov, V.V., Levchenkov, S.I., Anti- pin, M.Yu., and Shishkin, O.V., Mendeleev Commun., 1998, vol. 4, no. 4, p. 145. 43. Kogan, V.A., Lukov, V.V., and Shcherbakov, I.N., Ukr. Khim. Zh., 1999, vol. 65, no. 5, p. 65. 44. Popov, L.D., Shcherbakov, I.N., Levchenkov, S.I., Tupolova, Yu.P., Kogan, V.A., and Lukov, V.V., J. Coord. Chem., 2008, vol. 61, no. 3, p. 392. 45. Popov, L.D., Tupolova, Yu.P., Lukov, V.V., Shcherbakov, I.N., Burlov, A.S., Levchenkov, S.I., Kogan, V.A., Lyssenko, K.A., and Ivannikova, E.V., Inorg. Chim. Acta., 2009, vol. 362, no. 6, p. 1673. 46. Tupolova, Yu.P., Popov, L.D., Lukov, V.V., Shcher- bakov, I.N., Levchenkov, S.I., Kogan, V.A., Maev- skiy, O.V., Vlasenko, V.G., and Zubenko, A.A., Z. Anorg. Allgem. Chem., 2009, vol. 635, no. 3, p. 530. 47. Rakitin, Yu.V., Larin, G.M., and Minin, V.V., Inter- pretatsiya spektrov EPR koordinatsionnykh soedinenii (Interpretation of ESR Spectra of Coordinared Com- pounds), Мoscow: Nauka, 1993.