O. I. Askalepova

Protolytic and complexation properties of the cyclic thiosemicarbazone ligand

The acid-base properties of the thiourea based cyclic thiosemicarbazone have been studied. The tautomerism and complex formation ability of the thiosemicarbazone were investigated by the methods of quantum chemistry and electronic spectroscopy. The complexes of copper(II), nickel(II), cobalt(II), and mercury(II) were synthesized and their structure suggested.

Synthesis, structure, and complexing ability of hetarylhydrazones of glyoxylic acid

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.

Protolytic and complexing properties of hetarylhydrazones derived from o-tosylaminobenzaldehyde

New ligand systems were synthesized by condensation of o-tosylaminobenzaldehyde with quinolin-2-ylhydrazine and 1-methyl-1H-benzimidazol-2-ylhydrazine. Acid-base properties of the resulting hetarylhydrazones and their complexing power toward bivalent copper, nickel, and cobalt ions were studied. The stability constants of the complexes were determined.

Oligonucleotide cross-linking with copper ions. Spectral and quantum chemical study

Copper(II) complexes with synthetic oligonucleotides consisting of repeating adenine–thymine and guanine–cytosine complementary base pairs have been studied by UV spectroscopy and simulated by DFT quantum chemical calculations at the B3LYP/6-311G++(d,p) level of theory with inclusion of solvation (hydration) effects. The obtained data suggest selective interaction of copper(II) ions with guanine–cytosine complementary pairs, followed by DNA cross-linking at those sites.

Physicochemical study of new polydentane ligand systems based on 2,6-diformyl-4-tert-butylphenol

New polydentate ligand systems, products of condensation of 2,6-diformyl-4-tert-butylphenol with 1,3-diaminopropanol-2 and carbo(thiocarbo)hydrazide, were synthesized and their structure was determined based on the data of elemental analysis, 1H NMR and IR spectroscopy. The acid-base properties of bisazomethine I have been studied. Spatial structure and spectral properties of the ligand system were simulated using quantum-chemical calculations.

Crystal structure of the polycyclic oxidation product of 1′-phthalazinylhydrazone of 2-formylpyrrole

Phthalazinylhydrazone of 2-formylpyrrole is synthesized, the values of ionization constants are determined, and quantum chemical calculation of the geometry and total energy of possible tautomers is performed. The structure of the cyclic oxidation product of hydrazone 3-(1H-pyrrolyl-2)-[1,2,4]-triazolo(3,4-a)phthalazine existing in the crystal in the form of dimers linked by two hydrogen bonds is described.

Synthesis and physico-chemical study of complexation of glyoxylic acid aroylhydrazones with Cu(II) in solution and solid phase

A series of copper(II) binuclear metallochelates with glyoxylic acid aroylhydrazones have been synthesized. The composition and structure were established with infrared, UV-Vis, 1H NMR, extended X-ray adsorption fine structure spectroscopy as well as magnetochemical studies and potentiometry. The proton-donor and proton-acceptor features of the ligand systems play a key role in the formation of the complexes.

Copper(II), nickel(II), and zinc(II) complexes with o -tozylaminobenzaldehyde 4,6-dimethylpyrimidyl hydrazone

Abstracto-Tosylaminobenzaldehyde dimethylpyrimidyl hydrazone and its copper(II), nickel(II), and zinc(II) complexesare synthesized and studied. According to the X-ray diffraction data, the zinc(II) complex has the structure of a tetragonal pyramid with the N3O donor ligand environment. According to EPR and magnetochemistry data, the copper(II) complex has a similar structure of the chelate core. In the nickel(II) complex, the solvent molecule completes the coordination core to an octahedron.

Physico-chemical and theoretical investigation of the Schiff’s base of 2,6-diformyl-4-tert-butylphenol and m-aminocinnamic acid

Novel bis-azomethine, the product of condensation of 2,6-diformyl-4-tert-butylphenol and m-aminocinnamic acid, has been synthesized. The product structure and properties have been investigated by means of 1Н NMR, IR, and electronic spectroscopy as well as quantum-chemical simulation. Potential application of the bis-azomethine as a component of dye sensitized solar cells has been demonstrated.

Synthesis, physicochemical study, and quantum-chemical simulation of hydrazones based on 2-hydrazinoimidazoline

Abstract2-Imidazolinylhydrazones of salicylic aldehyde, 2-N-tosylaminobenzaldehyde, and 1-phenyl-3-methyl-4-formylpyrazolone-5 are synthesized and studied by the IR, NMR, and electronic spectroscopy. Quantum chemical calculations of geometry and total energy of possible tautomers in a vacuum and ethanol solution are carried out. It is shown that in all cases diazine tautomers are the most stable.