Radical anion of 1,4-diborabenzene

Abstract

Reduction of 1,4-difluoro-2,3,5,6-tetramethyl-1,4-diboracyclohexa-2,5-diene using potassium in dimeth-oxyethane proceeds in two steps: firstly, the acquisition of one electron yields the unstable radical anion [FB(MeCCMe)₂BF]·^–, isoelectronic with durosemiquinone; and secondly the potassium film removes the fluorine substituents and the radical anion [B(MeC-CMe)₂B]·^– is produced which is stable at room temperature and represents a novel heterocycle, tetramethyl-1,4-diborine.