Formation of large chelate rings and cyclometallated complexes from But2PCH2CH2CHMeCH2CH2PBut2 and platinum and palladium chlorides. Crystal structure of [Pd2Cl4{But2PCH2CH2CHMeCH2CH2PBUt2}2]

Abstract

Treatment of [PdCl₂(NCPh)₂] with Bu^t₂ PCH₂CH₂CHMeCH₂CH₂PBu^t₂(Q) gives the binuclear complex [Pd₂Cl₄(Bu^t₂PCH₂CH₂CHMeCH₂CH₂PBu^t₂)₂]. The crystal structure of this 16-atom ring complex shows that the two methyl substituents on the ring occupy ‘corner positions’ and the C₅ chains are not in the extended conformation. The crystals are monoclinic, space group Pn, with unit-cell dimensions a= 8.616(2), b= 28.485(5), c= 12.127(2)Å, β= 109.35(2)°, and Z= 2, final R= 0.07. A variable-temperature ³¹P n.m.r. study shows the ring to be fluxional. With [PtCl₂(NCPh)₂], Q gives a complex [(PtCl₂Q)_x](also fluxional) and a cyclometallated complex [graphic omitted]Bu^t₂)] abbreviated to [PtCl(P–C–P)], [PtCl₂Q] with CF₃COOH gives [Pt(OOCCF₃)(P–C–P)], and [PtCl(P–C–P)] with Na[BH₄] gives [PtH(P–C–P)]. Infrared and ¹H and ³¹P n.m.r. data are given.