Structure and properties of 1-acylpyrazolines

Proton magnetic resonance spectroscopy and the method of dipole moments demonstrated that 1-acylpyrazolines exist primarily in the s-trans form, which is stabilized by the repulsion of like-charged nitrogen and oxygen atoms. Simultaneous reduction of the C =O and C =N bonds was observed during the action of lithium aluminum hydride on 1-formyl-and 1-trifluoroacetylpyrazolines, which is explained by the relatively high polarity of the C=N bond.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 488–491, April, 1972.     

Reductive cleavage of dichalcogenide bonds

The kinetics of reductive cleavage of the dichalcogenide bond in dimeric Schiff's bases ArEEAr (E=S, Te) induced by indirect electron transfer byin situ generated bridged bispyridinium radical cations and biradicals was studied by cyclic voltammetry. It was shown that the dependence between the apparent rate constants of intermolecular electron transfer and the electron-withdrawing properties of diaryldichalcogenides is violated. The mechanisms of homogeneous (chemical) and heterogeneous (electrochemical) reductive cleavage of diaryldichalcogenides were discussed. For Part 2, see Ref. 1. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1522–1526, August, 1999.     

Synthesis, X-ray spectral, and magnetochemical study of copper complexes based on tridentate azomethines of 3-allylsalicylaldehyde

Tridentate azomethine ligands (H₂L) based on 3-allylsalicylaldehyde and o-aminophenol, o-aminothiophenol, or 2-ethylamino-5-nitroaniline were synthesized and identified by IR and ¹H NMR spectroscopies. The structure of complexes (Ia-Ic) was studied by magnetochemistry and EXAFS spectroscopy. Complexes Ia and Ib (X = O, S) are binuclear and exhibit antiferromagnetic exchange interaction: 2J = ?36.5 and ?950 cm^?1, respectively. Complex Ic (X = NC₂H₅) is mononuclear (μ_eff = 1.75 μ_B at 275 K and does not change as temperature decreases).     

Bis[2-(4′-Bromopyrazolyl-1′)-3-Tosylaminopyridinato]zinc(II): Synthesis,structure, and luminescence properties

2-(4′-Bromopyrazolyl-1′)-3-tosylaminopyridine (HL³) and its complex ZnL₂ (I) are synthesized, and their structures are studied by IR, UV, and ¹H NMR spectroscopy. The molecular structure of complex ZnL₂ is determined by X-ray diffraction analysis. The atomic structure of ZnL₂ is confirmed by the optimization of the molecular geometry using quantum-chemical calculations in the density functional theory approximation. The experimental bands in the absorption spectrum of complex I are interpreted on the basis of the calculations, and its photoluminescence properties are studied.     

Chemical and electrochemical syntheses of the binuclear zinc and cadmium chelates based on the sterically hindered Schiff bases

Chemical and electrochemical syntheses of a series of the zinc(II) and cadmium(II) complexes were carried out on the basis of sterically hindered Schiff bases, which are the condensation products of 4,6-di-tert-butyl-2-aminophenol with the salicylaldehyde derivatives (H₂L, H₂L¹). The structures and compositions of the synthesized binuclear complexes M₂L₂ and M₂L ₂ ¹ where M = Zn(II) and Cd(II), were proved by the data of elemental analysis, IR spectroscopy, and ¹H NMR spectroscopy. The structures of the Zn₂L₂ · 2Py and Zn₂L₂ · 2DMF dimers were proved by X-ray diffraction analysis. The electrochemical dissolution of zero-valence zinc and cadmium in methanol in the presence of equimolar amounts of H₂L and H₂L¹ made it possible to isolate dimeric complexes of the corresponding metals of the composition M₂L₂ and M_{2 2} ¹ .     

Binuclear and polynuclear complexes of Schiff bases

The data on the synthesis of binuclear and polynuclear homo- and heterometallic complexes of aromatic and heterocyclic (azole) Schiff bases are summarized and systematized. Influence is revealed of the structure (nature of aldehyde and amine moieties and intermetallic bridges) of azomethine binuclear copper chelates on their magnetic characteristics. The complexes with N,N-or S,S-bridging atoms are shown to lead, in general, to ferromagnetic exchange whereas O,O-intermetal binding leads to antiferromagnetic spin-spin coupling.     

Synthesis and reactivity of metal-containing monomers 76. Nanostructured materials obtained by controlled thermolysis of Ni,Co, and Cu chelate complexes with azomethine ligands

The controlled thermolysis of mono(Ni^II, Cu^II, and Co^II) and dinuclear (Ni^II, Cu^II, and Fe^II) chelate complexes with azomethine ligands, containing oxygen, nitrogen, and sulfur atoms in the chelate rings, was studied. The effect of the ligand environment on the thermal stability and composition of the resulting nanocomposites was examined. Comparative thermal analysis (DSC, DTA, and TGA) of the metal chelate complexes was performed. Their thermolysis products were characterized using elemental analysis, X-ray powder diffraction, scanning electron microscopy, and gel permeation chromatography. The magnetic properties of the nanocomposites obtained were analyzed.