Showing papers by "Natalya V. Chizhova published in 2013"

Synthesis and spectral properties of cobalt(II) and cobalt(III) tetraarylporphyrinates

Abstract: Reactions of 5,10,15,20-tetraphenylporphin, 5,10,15,20-tetra(4′-methoxyphenyl)porphyrin, and 5,10,15,20-tetra(4′-chlorophenyl)porphyrin with cobalt(II) acetate in dimethylformamide were studied by spectrophotometry. The corresponding cobalt(II) porphyrinates were synthesized and identified. The corresponding cobalt porphyrinates in +3 oxidation state were obtained by reaction of cobalt(II) 5,10,15,20-tetraphenylporphyrinate and cobalt(II) 5,10,15,20-tetra(4′-methoxyphenyl)porphyrinate with 2,3-dichloro-5,6-dicyano-p-benzoquinone in chloroform. The oxidation of cobalt(II) 5,10,15,20-tetra(4′-chlorophenyl)porphyrinate with hydrochloric acid in dimethylformamide leads to cobalt(III) porphyrinate.

Spectrophotometric study of 2,3,12,13-tetrabromo-5,10,15,20-tetraphenylporphyrin in the system 1,8-diazabicyclo[5.4.0]undec-7-ene-acetonitrile at 298 K. Deprotonation of the pyrrole rings and complex formation with Zn(OAc)2

Abstract: Acid-base and complexing properties of 2,3,12,13-tetrabromo-5,10,15,20-tetraphenylporphyrin in the system 1,8-diazabicyclo[5.4.0]undec-7-ene-acetonitrile were studied at 298 K by spectrophotometric titration. The titration of 2,3,12,13-tetrabromo-5,10,15,20-tetraphenylporphyrin with 1,8-diazabicyclo[5.4.0]-undec-7-ene was accompanied by successive deprotonation of the pyrrole nitrogen atoms with formation of the corresponding mono- and dianions, and the acid dissociation constants were determined. Complex formation of doubly deprotonated 2,3,12,13-tetrabromo-5,10,15,20-tetraphenylporphyrin with zinc acetate was studied.

Synthesis and properties of ms- and β-substituted Pt(II) and Pt(IV) tetraphenylporphyrinates

Abstract: The interaction of 5,10,15,20-tetraphenylporphyrin, 5,10,15,20-tetra-(4-chlorophenyl)porphyrin, 2-bromo-5,10,15,20-tetraphenylporphyrin, and 2,3,12,13-tetrabromo-5,10,15,20-tetraphenylporphyrin with platinum(II) chloride in boiling phenol has been studied. The corresponding platinum(II) porphyrinates have been synthesized; their subsequent treatment with bromine in chloroform resulted in platinum(IV) porphyrinates. The Pt(II) and Pt(IV)(Br)2 porphyrinates have been identified by elemental analysis, electron absorption, IR, and 1H NMR spectroscopy.

Axial coordination of imidazoles by meso-nitro substituted zn-octaethylporphyrins

Abstract: The study of complex formation between mono-, di-, triand tetranitro meso-substituted Zn-octaethylporphyrins with imidazole and 1-methylimidazole by UV-Vis titration method showed that binding ability of the Zn-porphyrins towards investigated N-containing small organic molecules depends on the number of electron-withdrawing nitro-groups in the macrocycle. Taking into account the fact that binding is accompanied by a clear and easily identifiable response in the UV-Vis spectra of the reaction mixture, triand tetranitro substituted Zn-porphyrins could be considered as molecular optical sensing devices for small heterocyclic substrates.

Synthesis and spectral properties of meso-substituted Ni2+ octaalkylporphyrinates

Abstract: Nickel(II) 3,7,13,17-tetramethyl-2,8,12,18-tetrabutylporphyrinate and its 5,15-diaza, -diphenyl, and -di(4-bromophenyl) derivatives have been synthesized by the reaction of nickel(II) chloride with corresponding tetrapyrrole ligands in dimethylformamide.

Spectrophotometric study of equilibrium association of cationic acids of tetraphenylporphyrin β-bromo-derivatives in acetonitrile-perchloric acid system at 298 K

Abstract: The basic properties of 2-bromo-5,10,15,20-tetraphenylporphyrin (I), 2,3,12,13-tetrabromo-5,10,15,20-tetraphenylporphyrin (II) and 2,3,7,8,12,13,17,18-octabromo-5,10,15,20-tetraphenylporphyrin (III) in the system of acetonitrile-perchloric acid at 298 K were studied using a method of spectrophotometric titration. The protonation of endocyclic nitrogen atoms of tetrapyrrole macrocycles was found to occur in two stages, therewith the increase in the number of bromine atoms in the structure of the macrocycle made easier the addition of the first proton compared with the second one. The ionization constant and the concentration ranges of existence of mono- and dication forms of the compounds were determined.

Metal-exchange reaction between cadmium tetraphenylporphyrinates and copper(II) in dimethylformamide

Abstract: The metal-exchange reaction of cadmium 5,10,15,20-tetraphenylporphyrinate (CdTPP) and cadmium 2-bromo-5,10,15,20-tetraphenylporphyrinate (CdTPPBr) with copper acetate (Cu(OAc)(2)) in dimethylformamide was studied spectrophotometrically. The kinetic parameters of the metal-exchange reaction were determined. A possible stoichiometric reaction mechanism was proposed.

Reaction of Metal Exchange of Cadmium 5,10,15,20-Tetraphenylporphyrinate and Its β-Bromo Derivative with Zinc Acetate in Dimethylformamide

Abstract: Metal exchange of cadmium 5,10,15,20-tetraphenylporphyrinate (CdTPP) and cadmium 2-bromo-5,10,15,20-tetraphenylporphyrinate (CdTPPBr) with zinc acetate in dimethylformamide was spectrophotometrically examined. The kinetic parameters of the metal exchange reaction were determined. A possible stoichiometric mechanism of the reaction was suggested. The effect of the bromo substituent in β-position of the pyrrole in the cadmium tetraphenylporphyrinate on the metal exchange reaction with Zn(OAc)2 in DMF was found.