Diisobutyl(phosphaneyl)alane: a simple PH2-transfer reagent for the synthesis of polyphosphaneyl compounds of silicon and germanium

Introduction of PH3 into a solution of diisobutylaluminium hydride in hexan e furnishes, under evolution of H-2, the title compound [iBu(2)AlPH(2)](3) (4) The alane 4 is probably trimer in noncoordinating solvents such as hydr ocarbons and shows only a marginal tendency in such solutions to undergo di ssociation. A nucleophilic transfer of the PH2 group in 4 onto E-X-compound s of group 14 elements (E = Si, Ge; X = Cl) succeeds only in the presence o f THF which transforms 4 to the corresponding monomeric, THF-solvated alane 5. The latter is a remarkable mild phosphaneylation reagent, which facilit ates access to Si(PH2)(4) (1), Ge(PH2)(4) (2), MeSi(PH2)(3) (6), and EtSi(P H2)(3) (7) more efficiently.