Synthesis and characterization of mono- and bimetallic complexes with phosphine–salicylaldimine ligands. The X-ray crystal structure of trans-PdCl2{Ph2P(CH2)3NCHC6H4-o-OH}2

Complexes of the type M{Ph2P(CH2)nNCHC6H4-o-OH}2 (n=3, 4 and M=cis- and trans-PdCl2, cis-PtCl2, cis,cis,trans-RuCl2(CO)2) have been synthesized by the reactions of the ligands with the appropriate metal precursors. All of the complexes are obtained in high yields, and, in all of the complexes, the ligands are coordinated solely through the phosphorus. Attempts to form bimetallic complexes by reaction of these complexes with either nickel acetate or diethylzinc give incomplete reactions and mixtures of products. A bimetallic Pd(II)–Ni(II) complex has been obtained by the reaction of {Ph2P(CH2)4NCHC6H4-o-O}2Ni and Pd(cod)Cl2. Crystals of this complex are yellow–brown but yield a green powder when ground. NMR spectra of the complex suggest that it is monomeric in solution. The X-ray crystal structure of trans-PdCl2{Ph2P(CH2)3NCHC6H4-o-OH}2 has been determined. The coordination geometry of the Pd is a nearly perfect, trans square plane containing two phosphines and two chlorides. The Pd–Cl bonds are nearly parallel to the P–CH2 bond, and the salicylaldimine groups lie on opposite sides of the plane formed by Pd, P and Cl.