Alane– and gallane–sulfur donor chemistry: synthesis of AlH3·NMe(CH2CH2)2S, {AlH2[µ-N(CH2CH2)2S]}2 and MH(SCH2CH2NEt2)2(M = Al or Ga)

Abstract

Reaction of N-methylthiomorpholine hydroiodide with LiAlH₄ in OEt₂ yielded the Lewis-base adduct of alane, AlH₃·NMe(CH₂CH₂)₂S 1, which is monomeric in benzene as the N-donor species. Thiomorpholine with H₃Al·NMe₃ also in OEt₂ afforded the metallated species {AlH₂[µ-N(CH₂CH₂)₂S]}₂2; in the solid-state dimers arising from bridging amido centres are weakly associated via intermolecular Al ⋯ S interactions at 3.22(3)Å. Treatment of 2-diethylaminoethanethiol hydrochloride with LiMH₄(M = Al or Ga) in OEt₂ or tetrahydrofuran generated the five-co-ordinate species MH(SCH₂CH₂NEt₂)₂(M = Al 3 or Ga 4), authenticated by X-ray crystallography as isostructural, chiral five-co-ordinate species in the solid, the N-donor groups occupying apical positions of trigonal-bipyramidal metal centres.