Cyclic NHC-stabilized silylphosphinoalanes and -gallanes

Abstract

Four-membered Al/Ga–P ring systems were prepared by thermal hydrogen elimination between the primary silylphosphine H₂PSitBuPh₂ and the metal hydride precursors [(Me₃N)MH₃] (M = Al, Ga). The obtained cycles [(Me₃N)HMP(SitBuPh₂)]₂ (M = Al: 1, Ga: 2) were functionalized by substituting the amine donor with the N-heterocyclic carbenes IPr and BImY to obtain the compounds [(NHC)HMP(SitBuPh₂)]₂ (IPr/Al: 3, BImY/Al: 4, IPr/Ga: 5, BImY/Ga: 6). All mentioned compounds feature an unusual external Lewis base stabilization as well as hydridic metal bound hydrogen atoms.