[Pt-2(PPh3)(4)(mu-S)(2)] as a metalloligand toward main-group Lewis acids. Crystal structures and bonding analysis of two low-coordinate BiCl3 adducts [Pt-2(PPh3)(4)(mu(3)-S)(2)BiCl3] and [Pt-2(PPh3)(4)(mu(3)-S)(2)BiCl2]PF6

Abstract

Addition of BiCl3 to [Pt2(PPh3)4(μ-S)2] gives [Pt2(PPh3)4(μ3-S) 2BiCl3], which undergoes dissociation and metathesis with NH4PF6 to give [Pt2(PPh3)4(μ3-S) 2BiCl2]PF6. An X-ray single-crystal diffraction analysis established two highly distorted square-pyramidal and tetrahedral structures, respectively. The four- and five-coordination numbers are unusually low among the known BiIII halide adducts. Fenske-Hall MO analysis offers an explanation to the structural characteristics with reference to the stereochemically active lone pairs, coordination numbers, uneven Bi - Cl and Bi - S lengths and the butterfly geometry of the {Pt2S2} core. These parameters are compared with those of the other intermetallics previously reported. @ 1997 Elsevier Science Ltd.