The chemistry of rhenium alkyls. Part III. The synthesis and reactions of hexamethylrhenium(VI), cis-trimethyldioxorhenium(VII), and the octa-methylrhenate(VI) ion

Abstract

The green, crystalline, paramagnetic (d¹) hexamethylrhenium, ReMe₆, has been prepared by interaction of tetramethyloxorhenium(VI), ReOMe₄, with trimethylaluminium. It is characterised by mass, i.r., and e.s.r. (reported separately) spectra. It reacts with dioxygen to give ReOMe₄ and with nitric oxide to give cis-trimethyldioxorhenium(VII), ReO₂Me₃: the latter is best prepared by the action of NO on ReOMe₄. The mechanism of this reaction is discussed and an intermediate of stoicheiometry ReO(CH₃)₃(CH₃NO) is characterised. N.m.r. spectra of the oxo-species are reported.

Interaction of hexamethylrhenium with methyl-lithium forms the octamethylrhenate(VI) ion, which can be isolated as the tetramethylethylenediamine (tmed) salt Li₂[ReMe₈]·tmed.

An improved synthesis of ReOMe₄ is given.