Scandium, yttrium, uranium, and thorium derivatives of the 1,4-bis(trimethylsilyl)cyclo-octatetraene dianion; the X-ray crystal structure of [Sc2(η-C8H6{1,4-(SiMe3)2})2(µ-Cl)2(µ-thf)](thf = tetrahydrofuran)

Abstract

Deprotonation of 1,4-bis(trimethylsilyl)cyclo-octa-2,5,7-triene affords the 1,4-bis(trimethylsilyl)cyclo-octatetraene dianion, which reacts with [UCl₄] or [ThCl₄] to give the sandwich compounds [M(η-C₈H₆{1,4-(SiMe₃)₂})₂], M = U or Th, with [UCl₂(BH₄)₂] to give [U(η-C₈H₆{1,4-(SiMe₃)₂})(η³-BH₄)₂], and with [ScCl₃(thf)₃] or [YCl₃(thf)₃](thf = tetrahydrofuran) to yield [{M(η-C₈H₆{1,4-(SiMe₃)₂})(η-Cl)}₂{thf}_n], M = Sc, n= 1; M = Y, n= 2; X-ray crystallography shows the latter scandium compound to possess a novel semi-bridging thf ligand.