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Volume 49, Nº 3 (2023)
Articles
Iron Tricarbonyl Complexes Based on N,N'-Disubstituted Phenanthrenediimines
Resumo
The oxidative addition of N,N'-disubstituted phenanthrenediimines to iron carbonyls was studied. The reactions of acceptor phenanthrenediimines with Fe2(CO)9 give iron(I) tricarbonyl complexes with anion-radical forms of the ligands. The synthesized compounds were characterized by NMR and IR spectroscopy. The structures of the complex based on N,N'-bis(3-trifluoromethylphenyl)phenanthrenediimine and imidazol-2-one ligand was established by X-ray diffraction (XRD) (CIF files СCDC nos. 2173471 and 2173472, respectively).
131-137
Complexes R2Sn(IV)L with O,N,O'-Donor Schiff Bases: Synthesis, Structures, and Redox Properties
Resumo
New tin(IV) complexes with O,N,O'-donor Schiff bases (L1H2–L4H2) of the (Ln)SnR2 type (R = Ph (I–III), Et (IV–VII)) are synthesized and characterized. The molecular structures of compounds I–III, VI, and VII in the crystalline form are determined by X-ray diffraction (XRD) (CIF files CCDC nos. 2181140 (I), 2181142 (II), 2181143 (III∙CH3CN), 2181141 (VI), and 2181139 (VII)). Tin complexes I–III and VI are mononuclear pentacoordinate compounds. Crystalline complex VII forms dimers via the pairwise bridging coupling between the oxygen and tin atoms of the mononuclear fragments. The redox-active ligand in the synthesized compounds exists as the iminobis(phenolate) dianion. The electrochemical properties of free ligands and complexes I–VII are studied. In the case of compounds I, II, IV, and V with tert-butyl substituents in the redox-active ligand, the formation of relatively stable monocationic and monoanionic species is electrochemically detected for the first time. The presence of the electroactive nitro group results in the destabilization of the oxidized forms of the complexes and induces the appearance of an additional peak in the cathodic range. The energy gaps between the frontier redox orbitals are determined by the electrochemical and spectral methods. The obtained parameters are close and vary in a range of 2.43–2.68 eV.
138-156
A New Biocompatible Metal-Organic Framework Prepared by Green Chemistry Methods
Resumo
A new biocompatible metal-organic framework [Mg(Mal)(H2O)](H2O) (H2Mal = malic acid) (I) was synthesized under solvothermal conditions, isolated in a pure state, and characterized by elemental analysis and X-ray diffraction. Compound I, which is the second example of a magnesium metal-organic framework based on malic acid, was prepared under drastic conditions of solvothermal synthesis. Cysteine or products of its decomposition were found to have a template effect on the formation of malic acid-based metal-organic frameworks under the chosen drastic conditions.
157-162
Cu(II), Ni(II), Co(II), Zn(II), and Pd(II) Complexes with (4Z)-4-[(2-Furylmethylamino)methylene]-5-methyl-2-phenylpyrazol-3-one: Synthesis, Structures, and Properties
Resumo
(4Z)-4-[(2-Furylmethylamino)methylene]-5-methyl-2-phenylpyrazol-3-one (HL) and its Cu(II), Ni(II), Co(II), Zn(II), and Pd(II) complexes with the ML2 composition are synthesized. The structures of the complexes are studied by elemental C,H,N analysis, IR spectroscopy, magnetochemical measurements, and quantum chemistry. The crystal structures of the copper(II) and cobalt(II) complexes are determined by X-ray diffraction (XRD) (CIF files CCDC nos. 2177619 and 2177622, respectively). Two deprotonated ligands are coordinated to the metal ions via the chelate mode by the nitrogen atom of the imino group and the oxygen atom of the hydroxy group of the ligand. The geometry of the copper(II) ion environment corresponds to a distorted planar square, whereas the cobalt(II) ion exists in a distorted tetrahedral environment. In the series of the compounds studied, fluorescence with a maximum at 431 nm and a quantum yield of 0.29 is observed for the Zn(II) complex in a solution of CH2Cl2. The synthesized enamine and metal complexes are tested for antibacterial, protistocidal, and fungistatic activities. All compounds are shown to have no fungistatic and antibacterial activities, and only a weak protistocidal activity is found for the copper and zinc complexes.
163-173
Novel Cobalt Bis-o-semiquinonato Complexes with Bidentate N-Donor Ligands
Resumo
Two new cobalt bis-o-semiquinonato complexes, (Pyz-Phen)Co(3,6-DBSQ)2 (I) and (Bpyz)Co(3,6-DBSQ)2 (II) (Pyz-Phen = pyrazino[2,3-f][1,10]phenanthroline, Bpyz = bipyrazine, 3,6-DBSQ = 3,6-di-tert-butyl-o-benzoquinone radical anion), were synthesized. According to X-ray diffraction data, both complexes have a trigonal-prismatic geometry of the inner coordination sphere. The distribution of C–O and Co–O bond lengths, which reflects the valence state of the metal and the ligands, indicates that the complexes are formed by cobalt(II) surrounded by two semiquinone radical anions. The results of magnetochemical measurements show that the pyrazino[2,3-f][1,10]phenanthroline complex is a derivative of low-spin divalent cobalt, whereas its bipyrazine structural analogue is a high-spin cobalt(II) derivative.
174-182
Specific Features of the Oxidative Addition of Triarylantimony to Dihydroxybenzoic Acids
Resumo
Tris(2-methoxyphenyl)antimony and tris(3-fluorophenyl)antimony react with 2,3-dihydroxybenzoic and 3,4-dihydroxybenzoic acids in the presence of tert-butyl hydroperoxide to form carboxycatecholato-О,О'-triarylantimony. Under similar conditions, tris(4-fluorophenyl)antimony reacts with 2,3-dihydroxybenzoic acid to form tris(4-fluorophenyl)antimony dicarboxylate. Structural features of the reaction products are determined by X-ray diffraction (XRD) (CIF files CCDC nos. 2126358 (I), 2124252 (II·H2O·Et2O), 2121839 (III·0.5С6Н6), and 2131083 (IV·2.5С6Н6).
183-192