SYNTHESIS, CHARACTERIZATION AND REACTIONS OF BIS[2(DIMETHYLAMINOMETHYL)PHENYL] DISELENIDE - ITS STRUCTURE AND THAT OF [2-(DIMETHYLAMINOMETHYL)PHENYL]SELENIUM BROMIDE

Bis[(2-dimethylaminomethyl)phenyl] diselenide (RSe)(2) was obtained by the organolithium route. It underwent facile reaction with stoichiome tric amounts of bromine and iodine to give the corresponding arylselen ium halides RSeBr and novel RSeI in which the selenium is covalently b onded to iodine. With an excess of bromine it gave the corresponding t ribromide RSeBr(3) but a similar reaction with iodine gave only RSeI. With diazomethane it gave the selenoether (RSe)(2)CH2 and with HCl the known bis(hydrochloride) (RSe)(2) . 2HCl. A catalytic conversion of a lkenes into allylic acetates using (RSe)(2) was carried out. The compo unds were characterised by elemental analyses, mass, multinuclear NMR (H-1, C-13, Se-77), IR, Fourier-transform-Raman spectrometry and condu ctance measurements. The compound RSeBr(3) shows evidence for the exis tence of Se ... N interaction in solution and was found to equilibrate between co-ordinated and non-co-ordinated forms. The structures of th e diselenide (RSe)(2) and its bromo derivative RSeBr were determined b y X-ray crystallography. The compounds are isostructural and exhibit S e ... N intramolecular co-ordination. The Se atom has T-shaped three-c o-ordination in both structures and the five-membered chelate rings fo rmed by the Se, C and N atoms are puckered and exist in an envelope co nformation. The Se ... N interaction in RSeBr [Se-N 2.143(6) Angstrom] is, however, considerably stronger than that in (RSe)(2)[Se(1)-N(1) 2 .856(3), Se(2)-N(2) 2.863(4) Angstrom].