Synthesis and NMR investigation of Pt(CN)(2)(diphosphine) and [Pt(CN)(triphosphine)]Cl complexes

Pt(CN)(2)(Ph2P(CH2)(n)PPh2) (n = 2,3,4) and Pt(CN)(2)(P-1-P-2) (P-1-P-2 = 1 -diphenylphosphino-2,1'-[(1-diphenylphosphino)-1,3-propanediyl]-ferrocene, 1-diphenylphosphino-2,1'-[(1-dicyclohexylphosphino)-1.3-propanediyl]-ferroc ene) were synthesised by reacting potassium cyanide and the corresponding P tCl2(diphosphine) complexes. PtCl(CN)(diphosphine) complexes were identifie d as minor products when KCN/PtCl2(diphosphine) molar ratio was kept below 2. The use of KCN in excess resulted in the formation of K2Pt(CN)(4). [Pt(C N)({Ph2P(CH2)(2)}(2)PPh)](+) complex cation and Pt(CN)(2))({Ph2P(CH2)(2)}(2 )PPh) five-coordinate covalent complex of fluxional behaviour were obtained at KCN/Pt ratio of 1 and 2, respectively. The platinum-cyano complexes wer e characterised by NMR spectroscopy. The direct Pt-CN bond was proved by (1 )J(Pt-195,P-31), (2)J(P-31,C-13) coupling constants by using sodium cyanide -C-13 for ligand exchange reactions. (C) 2000 Elsevier Science S.A. All rig hts reserved.