V. B. Panov

EPR spectra of halo-substituted 2,4,6-triphenylpyranyl radicals

The hyperfine structure of three halo-substituted pyranyl radicals, 2,6-bis(p-chlorphenyl)-4-phenylpyranyl, 2,6-bis(perfluorophenyl)-4-phenylpyranyl, and 2,6-bis(perfluorophenyl)-4-(o,p-dichlorophenyl)pyranyl, was investigated by EPR. The EPR spectra contained splitting from the protons of the aromatic rings and magnetic fluorine nuclei. An “ortho-effect” phenomenon was detected, the ratio of the constants of splitting on the ortho and para fluorine atoms aFn/aFo=2, unlike in the case of unsubstituted pyranyl radicals, where aHn≃aHO.

Synthesis and reactivity of 10-Alkylphenotellurazines

The reaction of N-alkyl-2,2′-dilithium diphenylamines with tellurium diiodide yields derivatives of a new heterocyclic system, phenotellurazine. 10-Alkyl-phenotellurazines readily form derivatives containing tetra- and tricoordinated tellurium, form complexes with metal salts and rhodium(I) carbonyl chloride, and by bromination and nitration give 3,7-dibromo- or 3-nitro-, 3,7-dinitro, and 1,3, 7,9-tetranitro derivatives.

4-o-Carboranylpyrylium perchlobates and stable free radicals based on them

The corresponding o-carboranylpyrylium perchlorates were obtained from 4H-pyrans of the o-carborane series under the influence of 70% HClO4 in acetic anhydride or 2,2′,4,4′-tetramethoxydiphenylammonium perchlorate. The carboranylpyranyl free radicals were studied by EPR spectroscopy, and it was shown that the unpaired electron is localized in the carborane ring.