(Ferrocenylmethyl)phosphine, an air-stable primary phosphine

Abstract

Removal of formaldehyde from the readily prepared ferrocenyl (R) hydroxymethylphosphine RCH₂P(CH₂OH)₂ with one mole equivalent of Na₂S₂O₅ gave the completely air-stable primary phosphine RCH₂PH₂ as a crystalline, sublimable solid. With [Mo(CO)₆] both mono-, [Mo(CO)₅(RCH₂PH₂)], and di-substituted, [Mo(CO)₄(RCH₂PH₂)₂], products are readily formed, and both were characterised by structure determinations. Reaction with [{RuCl₂(p-cym)}₂] (p-cym = p-cymene) resulted in bridge splitting to give the complex [RuCl₂(p-cym)(RCH₂PH₂)]. With [Ru₃(CO)₁₂], RCH₂PH₂ reacted in analogous fashion to other primary phosphines, with two isolated products [Ru₃(µ-H)₂(CO)₉(µ₃-PCH₂R)] and [Ru₄(CO)₁₁(µ₄-PCH₂R)₂] containing cluster capping RCH₂P phosphinidine ligands, the former characterised by a structure determination. Thus, the phosphine appears to show typical co-ordinative properties of a primary phosphine, but has the added advantage of being air-stable.