S. P. Solodovnikov

Nanodispersed cobalt particles in a thermolysed poly(acrylonitrile) matrix

The formation of nanodispersed (D ≈ 10nm)β-Co particles in a polymeric matrix is demonstrated, by thermolysing films of poly(acrylonitrile) containing homogeneously distributed [Co(dimethylformamide)62+][Co(CO)4–]2. Superparamagnetic behaviour is evident in these particles as determined by ferromagnetic resonance. Small-angle X-ray scattering is used to quantify the average particle size. The size of the Co particles can be controlled either by varying the thermolysis conditions or the loading of Co in the films prior to thermolysis.

Ion pairs in system: 3,6-di-tert-butyl-o-benzoquinone-metal

1. n n3,6-Di-tert-butyl-o-benzosemiquinone can exist in ether solvents as “contact” and “solvent”-separated pairs. The equilibrium constants of the transition between these forms were determined. n n n n n2. n nThe equilibrium constants between the solvated and unsolvated semiquinone forms were determined in a mixture of diethyl ether and isopropanol, and the unit rate constants of the transition between them were found.

Spectroscopic study of copper(II) complexes with 1,4,7-tris(dihydroxyphosphorylmethyl)-1,4,7-triazacyclononane and 1,4,7-tris(β-dihydroxyphosphorylethyl)-1,4,7-triazacyclononane

The reaction of 1,4,7-tris(dihydroxyphosphorylmethyl)-1,4,7-triazacyclononane and 1,4,7-tris(β-dihydroxyphosphorylethyl)-1,4,7-triazacyclononane with divalent copper over a wide pH range in aqueous solution has been studied using electronic, vibrational, and ESR spectroscopy. Normal and protonated complexes of both compounds have a pentacoordinate structure of the tetragonal type with coordination of three nitrogen atoms and two phosphonic groups. The difference lies in the different degree of distortion and flexibility of the square-pyramidal polyhedron.

Investigation by the ESR method of proton exchange in 3,6-di-tert-butyl-2-hydroxyphenoxyl

1. n nFor 3,6-di-tert-butyl-2-hydroxyphenoxyl (I), an intermolecular proton exchange of the hydroxyl group of the radical with acetic and trifluoroacetic acids was detected. In this case the rate of exchange increases with increasing strength of the acid. n n n n n2. n nThe thermodynamic data on the solvation of radicals by acids, which leads to an inhibition of the intramolecular migration of hydrogen in the radical (I), were determined from the ESR spectra. n n n n n3. n nFrom the kinetic data it follows that the solvation of radicals, inhibiting intramolecular migration, is not directly related to the kinetics of intermolecular proton exchange.

EPR studies of anion–radicals formed by reduction of perfluorinated α-triketones with some metals of groups I–III

Abstract Reaction of α,β-bis-fluorosulfatoketones i -C 3 F 7 (CFOSO 2 F) 2 C(O)R F , (R F =C 2 F 5 , i -C 3 F 7 ) with AcONa/AcOH afforded perfluoro-α-triketones i -C 3 F 7 C(O)C(O)C(O)R F , (R F =C 2 F 5 , i -C 3 F 7 ). Reduction of these triketones with metals (Li, Na, K, Mg, Cd, Zn, Tl) in THF was studied by EPR spectroscopy. Anion–radicals with unsymmetrical distribution of charge and spin densities are formed in one-electron reduction of the triketones. Unlike hydrocarbon α-polyketones, perfluorinated triketones can undergo three-electron reduction to form paramagnetic allyl tisalkoxides.

Reactions of Cr, Mo, W, and Mn carbonyls with 3,6-di-tert-butyl-o-quinone under the action of elastic wave pulses

Solid-state reactions of Cr, Mo, W, and Mn carbonyls with 3,6-di-terl-butyl-o-benzoquinone (Q) proceeding in molded powder-like mixtures (carbonyl-Q) treated with pulses of elastic waves were studied. The products of the reactions of Q with Cr(CO)6, Mo(CO)6, and W(CO)6 are paramagnetic serniquinone complexes of Cr, Mo, and W. The formation of two semiquinone complexes with one or two manganese atoms was detected in the reaction of Mn2(CO)10 with Q.

Investigation of EPR spectra of anion radicals of alkylenediphosphine dioxides and diaryl (carbamoylmethyl)phosphine oxides

It has been found that the length of the alkylene bridge in anion radicals of alkylenediphosphine dioxides influences the EPR spectra — an effect that is related to differences in structure of the ion pair. Temperature-dependent changes in the EPR spectra of anion radicals of diaryl (carbamoylmethyl)phosphine oxides are related to retarded rotation of the fragments of the anion radicals around the C-C bridge bond.

Free radical addition of oxygen containing compounds to internal perfluoroolefins

Abstract Reaction of internal perfluoroalkenes with aliphatic alcohols, aldehydes or ethers under UV irradiation were studied. 1:1 adducts were found to be the dominant or the only products of the reactions in all cases. Stereochemistry and regioselecticvity of the transformations were investigated. Radical intermediates of the reactions were registered by ESR method, and their structure and reactivity were studied. Hindered rotation of the substituents in radical derivatives of perfluoro-4-methylpentene-2 was observed.

Dissociation of 1, 4,7,10-tetrakis(dihydroxyphosphorylmethyl)-1,4, 7,10-tetraazacyclododecane and 1,5,8,12-tetrakis-(dihydroxyphosphorylmethyl)-1,5,8,12-tetraazacyclotetradecane and their complexation with divalent copper

Conclusions1.The study of the processes of acid dissociation revealed that 1,4,7,10-tetrakis(dihydroxyphosphorylmethyl)-1,4,7,10-tetraazacyclododecane has a dibetaine structure, that 1,5,8,12-tetrakis(dihydroxyphosphorylmethyl)-1,5,8,12-tetraazacyclotetradecane has a tribetaine structure, and that the betaine protons dissociate last.2.When complexes of 1,4,7,10-tetrakis(dihydroxyphosphorylmethyl)-1,4,7,10-tetrazacyclododecane and 1,5,8,12-tetrakis(dihydroxyphosphorylmethyl)-1,5,8,12-tetraazacyclotetradecane with divalent copper are formed in an aqueous solution, all the nitrogen atoms in the ring, as well as one or two phosphonic groups, participate in the coordination over a broad range of pH values.

Thermodynamics and kinetics of the complexing of thallium 3,6-di-tertbutyl-o-benzosemiquinolates with some complexing agents

Conclusions1.Complexes of thallium o-benzosemiquinolates with neutral organophosphorus ligands were detected by EPR spectroscopy. The thermodynamic and kinetic parameters of the complexing process were calculated.2.The mobility of the ligand plays a decisive role in the coordination of the ligand with thallium o-semiquinolate.