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

Complexes of the type M{Ph2P(CH2)(n) N=CHC6H4-o-OH}(2) (n = 3, 4 and M = ci s- and trans-PdCl2, cis-PtCl2, cis,cis,trans-RuCl2(CO)(2)) have been synthe sized by the reactions of the ligands with the appropriate metal precursors . All of the complexes are obtained in high yields, and, ill all of the com plexes, the ligands are coordinated solely through the phosphorus. Attempts to form bimetallic complexes by reaction of these complexes with either ni ckel acetate or diethylzinc give incomplete reactions and mixtures of produ cts. A bimetallic Pd(II)-Ni(II) complex has been obtained by the reaction o f (Ph2P(CH2)(4)N=CHC6H4-o-O}(2)Ni and Pd(cod)Cl-2. 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 structu re of trans-PdCl2 {Ph2P(CH2)(3)N=CHC6H4-o-OH)(2) has been determined. The c oordination geometry of the Pd is a nearly perfect, trans square plane cont aining two phosphines and two chlorides. The Fd-CI bonds are nearly paralle l to the P-CH, bond, and the salicylaldimine groups lie on opposite sides o f the plane formed by Pd, P and Cl. (C) 2001 Elsevier Science B.V. All righ ts reserved.