D. A. Garnovskii

The novel azomethine ligands for binuclear copper(II) complexes with ferro- and antiferromagnetic properties

A series of novel binuclear ferro- and antiferromagnetic Cu(2+) chelates of structurally broadly varied Schiff bases (derived from o-tosylamino(hydroxyl)benzaldehydes and monoalkylated o-phenylenediamine, o-aminophenol, o-aminothiophenol, 1,2-diaminobenzimidazole, 1-aminobenzimidazoline-2-thione) and β-diketimines (derived from 2,6-di-i-Pr-aniline) has been prepared. The tautomerism of the ligands and structureof their copper complexes have been studied with the use of IR, 1H NMR EPR and EXAFS spectroscopy. Molecular and crystal structure of a β-diketimine copper dimer has been determined by X-ray crystallography. The magnetic measurements (2–300 K) performed for all the complexes showed that the ferro- and antiferromagnetic character of the exchange interaction depends both on the structure of the coordination site (origin of the ligating centers) and the structure of the ligands (in particular, on the type of the cycle annelated to the bridging fragment). Whereas S-binding metal chelates 13 (X = NTs, Y = S, R = H) are diamagnetic, the complexes 15 with annelated azole moieties are ferromagnetic.

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.

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.

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.

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.

Molecular Design of New Magnetically Active Copper Complexes with Heteroaromatic Schiff Bases and Azo Compounds

Copper chelates with tridentate ligands containing pyridine or pyrazole ring at the azomethine or azo fragment were synthesized by chemical electrochemical methods, and their structure was characterized by the EXAFS spectra. Thermal magnetochemical analysis of the complexes revealed antiferromagnetic exchange interaction in all complexes. The exchange interaction parameter of the complex containing an N-tosylamino group in the ortho position with respect to the azomethine group is much lesser than that of the corresponding complex having an oxygen atom in the same position. The copper chelate derived from azopyrazole ligand shows low-temperature ferromagnetic phase transition.

Metal chelates of benzeneazo-N-tosyl-2-naphthylamine

New Cu(II), Co(II), and Pd(II) complexes with benzeneazo-N-tosyl-2-naphthylamine are synthesized by chemical and electrochemical methods and characterized by IR, 1H NMR, and XRD. XRD was used to determine that two six-membered metal rings are formed in transplanar Ni(II) and Pd(II) complexes.

Synthesis, structure, photo- and electroluminescence studies of bis[2-(N-tosylamino)benzylidene-4′-dimethylaminophenylaminato]zinc

A new bis[2-(N-tosylamino)benzylidene-4′-dimethylaminophenylaminato]zinc complex was synthesized, its structure was studied by methods of elemental analysis, IR spectroscopy, 1H NMR spectroscopy, X-ray absorption spectroscopy, and quantum chemical calculations. Electron absorption and photoluminescence spectra of the zinc complex were investigated. An OLED device based on it was made and found to emit “soft” yellow light with CIE coordinates (x = 0.431, y = 0.537) and radiation luminance 1300 cd m−2 at a working voltage of 14 V.

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 M2L21 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 M221.

New magnetoactive copper complexes with Schiff’s bases

Tridentate azomethine ligands with N2O and N3 donor atoms and their copper complexes have been synthesized and characterized. Magnetochemical measurements in the temperature range of 5–300 K show that the change in the coordination environment induces the change in the sign of exchange coupling in the molecules of complexes.