Synthesis and characterization of water-soluble palladium(II)-functionalized diphosphine complexes

Abstract

Water-soluble functionalized bis(phosphine) ligands L ( a– h) of the general formula CH 2(CH 2PR 2) 2, where for a: R = (CH 2) 6OH; b– g: R = (CH 2) n P(O)(OEt) 2, n = 2–6 and n = 8; h: R = (CH 2) 3NH 2 ( Scheme 1), have been prepared photochemically by hydrophosphination of the corresponding 1-alkenes with H 2P(CH 2) 3PH 2. Water-soluble palladium complexes cis-[Pd( L)(OAc) 2] ( 1– 8) were obtained by the reaction of Pd(OAc) 2 with the ligands a– h in a 1:1 mixture of dichloromethane:acetonitrile. The water-soluble phosphine ligands and their palladium complexes were characterized by IR, 1H and 31P NMR. A crystallographic study of complex 1 shows that the Pd(II) ion has a square planar coordination sphere in which the acetate ligands and the diphosphine ligand deviate by less than 0.12 Å from ideal planar.