Preparation and characterization of palladium and platinum complexes bearing 1,8-bis[(diphenylphosphino)methyl]naphthalene

Abstract

Reaction of MCl₂(cod) (M = Pd, Pt) with 1,8-bis[(diphenylphosphino)methyl]naphthalene (1,8-dpmn) gave MCl₂(1,8-dpmn) 1 (M = Pd), 2 (M = Pt), as confirmed by X-ray analyses. Complex 1 reacted with xylyl isocyanide a (XylNC) in the presence of NaPF₆ to give [Pd(1,8-dpmn)(XylNC)₂](PF₆)₂3a. Reactions of dinuclear complexes [M₂(RNC)₆](PF₆)₂ (4: M = Pd, 5: M = Pt; R = Xyl (a) or 2,4,6-Me₃C₆H₂ (b) (Mes)) with one or two equiv. of 1,8-dpmn gave [M₂(1,8-dpmn)(RNC)₄](PF₆)₂6 (M = Pd) and 7 (M = Pt), or [M₂(1,8-dpmn)₂(RNC)₂](PF₆)₂8 (M = Pd) and 9 (M = Pt). The structures of 6b, 7b and 8b were confirmed by X-ray analyses. Reaction of [Pd₂Cl₂(XylNC)₄] with two equiv. of 1,8-dpmn in the presence of NaPF₆ gave 8a, whereas the reaction in the presence of NH₄PF₆ produced 10a together with 7a. It was confirmed by an X-ray analysis of 10a that the crystal lattice is constructed by two types of cations (3a and two 2,2,6,6-tetramethyl-4-piperidonium) and four PF₆ anions. Photochemical reaction of 6a or 8a in CH₂Cl₂ led to cleavage of the Pd–Pd bond, giving [PdCl(XylNC)₃](PF₆) and [PdCl(1,8-dpmn)(XylNC)](PF₆).