Synthesis and Platinum Complexes of an Alane-Appended 1,1′-Bis(phosphino)ferrocene Ligand

An aryldimethylalane-appended analogue of 1,1'-bis(diphenylphosphino)ferrocene, FcPPAl, was prepared, and reaction with [Pt(nb)(3)] (nb=norbornene) afforded [Pt(eta(2)-nb)(FcPPAl)] (1). Heating a solution of 1 to 80 degrees C resulted in crystallization of [{Pt(FcPPAl)}(2)] (2), whereas treatment of 1 with C2H4, C2Ph2, H-2, or CO provided [PtL(FcPPAl)] [L=C2H4 (3), C2Ph2 (4)], [PtH2(FcPPAl)] (5), and [Pt(CO)-(FcPPAl)] (6). In all complexes, the FcPPAl ligand is coordinated through both phosphines and the alane. Whereas 2 adopts a T-shaped geometry at platinum, 3-5 are square-pyramidal, and 6 is distorted square-planar. The hydride and carbonyl complexes feature unusual multicenter bonding involving platinum, aluminum, and a hydride or carbonyl ligand.