Artur Vashurin

A new water-soluble sulfonated cobalt(II) phthalocyanines: Synthesis, spectral, coordination and catalytic properties

Novel complexes of cobalt(II) with sulfonated derivatives of phthalocyanines are synthesized. The influence of the sulfonated groups number in peripheral substituent on solubility of macrocycle and ability to form ordered structures in solution is showed. Transition from H-aggregates to monomeric phthalocyanine structures and sandwich-type dimers was found during formation of metallophthalocyanine complexes with 1,4-diazabicyclo(2.2.2)octane. The catalytic activity of metallophthalocyanines was studied on the model of Merox process.

Novel aqueous soluble cobalt(II) phthalocyanines of tetracarboxyl-substituted: Synthesis and catalytic activity on oxidation of sodium diethyldithiocarbamate

Enhancement of the catalytic activity of phthalocyanine catalysts by immobilizing them on polymer matrix has been studied. It has been found that the immobilization of cobalt(II) phthalocyanines on polymers enhances their catalytic activity in the oxidation of sodium diethyldithiocarbamate by air oxygen under mild conditions.

Self-Association of Sulfo Derivatives of Cobalt Phthalocyanine in Aqueous Solution

Sulfo derivatives of cobalt phthalocyanine containing naphthalene fragments have been synthesized, and their self-association and molecular complexation with pyridine in aqueous solution have been studied by spectrophotometry. The dissociation constants of the dimeric associates have been determined. The effects of the number of functional groups in the peripheral substituents and of the axial ligand on the phthalocyanine dimerization process have been revealed.

Catalytic properties of polymer matrix-immobilized cobalt complexes with sulfonated phthalocyanines

Enhancement of the catalytic activity of phthalocyanine catalysts by their immobilizing on polymer matrices has been studied. It has been found that the immobilization of sulfonated cobalt phthalocyanines on polymers enhances their catalytic activity in the oxidation of sodium diethyldithiocarbamate with air oxygen under mild conditions.

Kinetics and mechanism of the oxidation of dithiocarbamic acids in the presence of Co(II) phthalocyaninetetacarboxylic acid

The present work contains kinetic data of the oxidation of sodium diethyldithiocarbamate in the presence of phthalocyanine catalysts. It is shown that the nature of the peripheral substituent has a great influence on the self- - association of phthalocyanines and on their catalytic activity. A mechanism of the oxidation of sodium diethyldithiocarbamate involving the formation of a triple complex of the substrate, the reduced form of the catalyst and oxygen is offered. It is also shown that the oxidation mechanism of dithiocarbamic acids is different from that for cysteine.

Symmetrical and difunctional substituted cobalt phthalocyanines with benzoic acids fragments: Synthesis and catalytic activity

Difunctional and symmetric phthalonitriles were synthesized by nucleophilic substitution of brome and nitro-group in 4-bromo-5-nitro-phthalonitrile for residues 4-amino-, 4-hydroxyl- and 4-sulfanyl benzoic acid. Symmetrical and difunctional substituted cobalt phthalocyanines were obtained by template synthesis based on mentioned phthalonitriles. Their spectral properties and catalytic activity in aerobic oxidation of sodium N,N-carbomoditiolate were investigated.

Coordination and acid-base properties of meso-nitro derivatives of β-octaethylporphyrin

Spectrophotometric method is used to study the acid-base and coordination properties of a series of porphyrins with a continuously increasing degree of macrocycle deformation resulting from the introduction of strong electron — withdrawing substituents: 2,3,7,8,12,13,17,18-octaethylporphyrin (1), 5-nitro-2,3,7,8,12,13,17,18-octaethylporphyrin (2), 5,15-dinitro-2,3,7,8,12,13,17,18-octaethylporphyrin (3), 5,10,15-trinitro-2,3,7,8,12,13,17,18-octaethylporphyrin (4), and 5,10,15,20-tetranitro-2,3,7,8,12,13,17,18-octaethylporphyrin (5). It is found that the values of total basicity constants obtained for the investigated compounds consistently diminish with an increase in the number of meso-substituents: 11.85 (1) < 10.45 (2) < 10.31 (3) < 10.23 (4) < 9.56 (5). The values of the combined acidity constants of porphyrins (4–5) obtained in acetonitrile-DBU system at 298 K are pKa = 10.90 and 10.40 respectively. The reaction of complex formation between the porphyrins and their dianionic forms with zinc acetate was studied. It is shown that two opposing factors, the steric and electronic effects of the substituents, change the acid-base and coordination properties of the above series of compounds.

Catalytic properties of cobalt complexes with tetrapyrazino porphyrazine and phthalocyanine derivatives

The catalytic activity of cobalt complexes with octaphenyltetrapyrazinoporphyrazine and phthalocyanine derivatives containing branched peripheral substituents is studied in heterogeneous catalysis of the oxidation of sodium diethyldithiocarbamate (SDC) with atmospheric oxygen. Cobalt phthalocyanines are shown to display higher catalytic activity than cobalt complexes with octaphenyltetrapyrazinoporphyrazine. The highest efficiency of heterogeneous catalysts is attained at temperatures of 298–303 K.

Effect of the solvation properties of the solvent on the formation of associated structures of water-soluble Co(II) phthalocyanines

Self-association processes of sulfonated cobalt phthalocyanine derivatives were studied. The effects of the size of peripheral substituent and the solvation properties of the solvent on the formation of H- and J-aggregates of metal phthalocyanines were demonstrated. The possibility to control the associative equilibrium of metal phthalocyanines via coordination to DABCO was established. The introduction of DABCO was found to induce dissociation of H- and J-aggregates followed by the formation of sandwich type dimers.

Self-association of sulfo derivatives of cobalt phthalocyaninates in the presence of 1,4-diazabicyclo[2.2.2]octane

Complex formation between water-soluble cobalt(II) phthalocyaninates and 1,4-diazabicyclo[2.2.2]-octane has been studied. The formation of the 1: 1 molecular complex and the 2: 1 sandwich-type dimers has been confirmed. The sandwich-type dimers and the J-aggregates involving the peripheral groups of the macrocycle are formed in ethanol medium. Stability constants of the molecular complexes have been determined, and the effect of size of the peripheral substituents on the dimeric structures stability has been elucidated.