A. S. Burlov

Synthesis of cobalt(II), nickel(II) and copper(II) complexes with 2-(2-hydroxyphenyliminomethyl)-1-(4-methyl-phenylsulfonamido)benzene and crystal structures of {bis(methanol)[2-(2′-N-tosylaminophenyl)iminomethyl]phenolato}nickel(II) and {bis(2,2′-bipyridine)[2-(2′-N-tosylaminophenyl)iminomethyl]phenolato}copper(II)

Abstract Electrochemical oxidation of metal anodes (cobalt, copper and nickel) in acetonitrile solutions of 2-(2-hydroxyphenyliminomethyl)-1-(4-methyl-phenylsulfonamido)benzene (H2L) gave [CoL], [CuL] and [NiL] complexes. When 1,10-phenanthroline (phen) or 2,2′-bipyridine (bipy) was added to the electrolytic cell, the mixed complexes [MLL′] (M=Co, Cu, L′=bipy or M=Ni, L′=phen) were obtained. A binuclear compound of composition [Ni2L2(MeOH)4] (1) was synthesized by reaction of the ligand H2L and nickel(II) acetate in methanol. X-ray structure determination showed the compound to be binuclear, with each nickel atom coordinated to two nitrogen and two bridging phenol oxygen atoms of two dianionic ligands and two methanol molecules, in an octahedral environment. The crystal structure of [CuLbipy] (2) was determined by X-ray diffraction; with the copper atom in a distorted bipyramidal environment defined by the two bipyridine nitrogen atoms and by the phenolic oxygen and the nitrogen atoms of the dianionic ligand. The electronic and vibrational spectral data of the complexes are discussed and related to the structure.

New magnetically active metal complexes of tridentate Schiff bases of phenylazosalicylaldehyde

The bidentate chelate Cu(II) complexes of phenylazosalicylaldehyde azomethines are synthesized for the first time and their magnetic properties are studied. The complexes with the intermetallic bridge of the nitrogen atoms are characterized by the antiferromagnetic interaction, whereas the ferromagnetic exchange is typical of analogous coordination compounds with the sulfur bridge.

SOME ASPECTS OF COMPETITIVE COORDINATION OF β-DIKETONES AND NITROGEN-CONTAINING LIGANDS

Abstract Different coordination modes for transition metal atoms with typical chelating ligands such as β-diketones, o-oxyazomethines, azoles and azines are reviewed. Factors influencing the coordination such as ligand structure, methods and conditions of the synthesis, nature of solvent and specific hard-soft interactions are emphasized.

DIRECT ELECTROSYNTHESIS OF METAL COMPLEXES: STATE OF THE ART

Abstract Recent results on the electrosynthesis of metal complexes are reviewed. The basic principles of such syntheses and the main factors that influence the process quality are covered. The main structural characteristics of each type of coordination compound obtained by this method are discussed. The large number of publications testify to the wide application of direct electro-synthesis to obtain molecular complexes and metal chelates. In addition, this manuscripts shows the necessity of developing this technique to obtain π-complexes, compounds with macro-cyclic ligands and lanthanides complexes.

Tribochemically active chelate complexes of salicylideneimines

N-Alkylsalicylideneimines and their complexes with 3d metals were obtained by chemical (from metal salts) and electrochemical methods (from metals in the zero oxidation state). The compounds obtained were characterized by IR and 1H NMR spectroscopy and X-ray diffraction analysis. According to crystallographic data, nickel bis(chelate) exists in the trans-planar configuration. A friction test revealed that the tribotechnical characteristics of lubricating formulations are substantially enhanced in the presence of N-alkylsalicylideneiminates.

Transition metal complexes with 2-(N-tosylamino)benzaldehyde 1-phthalazinylhydrazone

Abstract2-(N-Tosylamino)benzaldehyde 1-phthalazinylhydrazone (H2L) and its complexes with Cu(II), Ni(II), and Mn(II) were obtained. The acid-basic properties of the hydrazone were studied using potentiometry and spectrophotometry. The experimental data were compared with the results of quantum-chemical DFT calculations. The structure of the binuclear complex [Cu2L2] was determined using X-ray diffraction. The broken symmetry approach was used to calculate the exchange coupling constant of the copper ions.

Molecular design of azomethine complexes

Data on the coordination chemistry of azomethines, which are based on the molecular design concept formulated and developed by V.I. Minkin and his disciples, are generalized and systematized. Particular attention is given to the methods for targeted synthesis of five- and/or six-membered chelates containing chalcogen atoms (S, Se, and Te) and nonstandard (heteroleptic, molecular, and supramolecular) structures. Achievements in the design of magnetically active and luminescent complexes and azomethine complex additives to lubricants are discussed.

Synthesis of transition metal complexes with heteroazomethinic ligands: a comparison of traditional and electrochemical methods

Abstract Transition metal complexes (M = Cu, Ni, Co, Pd, Zn and Cd) containing azomethinic ligands have been synthesized by conventional chemical methods and by direct electrochemical dissolution of the sacrificial metal anode. The resulting complexes were characterized by elemental analysis, IR and EPR-spectra and magnetochemical data. The influence of the type of metal, the peculiarities of the ligand structure and the methods an synthesis of metal chelates on their physico-chemical properties and structure are examined.

New ferro-and antiferromagnetic complexes of tridentate azomethines with copper

Tridentate azomethine ligands with N2O4 and N3donor atoms and their copper complexes were synthesized and characterized. The dimeric structure of copper(II) chelates was confirmed by EXAFS studies. Complexes based on 2-tosylaminobenzaldehyde azomethines tend to undergo ferromagnetic exchange, whereas similar salicylaldehyde derivatives have antiferromagnetic exchange.

CRYOSYNTHESIS OF COORDINATION AND ORGANOMETALLIC COMPOUNDS: HISTORY AND PRESENT STATE

Abstract Interactions of metals with inorganic and organic ligands including polymers are reviewed. Direct methods of synthesis have many possibilities in comparison to conventional synthetic methods. However, cryosyntheses with chelate-forming ligands have not been sufficiently devel—oped at the present time. Cryosyn thesis is especially recommended for preparation of compounds difficult to obtain by traditional methods.