Synthesis, Spectroscopic, and Structural Studies of the Methylpalladium(II) Complexes [{PdMe(SMe2)X}2] (X = Cl, Br, or I); Crystal Structure of trans-[{PdMe(SMe2)(mu-Cl)2]

Abstract

The complexes [{PdMe(SMe2)X}2] (X = Cl, Br, or I) have been prepared by reaction of trans-[Pd(SMe2)2X2] with halide-free methyllithium (X = Cl or Br), and reaction of trans-[Pd(SMe2)2Cl2] with methyllithium containing lithium iodide (X = I) in diethyl ether at -60 to -15 C under nitrogen. Other synthetic routes to the bromo- and iodo-complexes are also described. The crystal structure of the chloro-complex [{PdMe(SMe2)(mu-Cl)}2] has been determined by single-crystal X-ray diffraction at 295 K and refined by least-squares methods to R = 0.025 for 1914 independent 'observed' reflections [space group P2,/n, a = 10.792(4), b = 7.373(2), c = 9.1 31 (5) A, beta = 109.03(3), and Z = 2]. The centrosymmetric dimeric molecules have trans stereochemistry with bridging chloro- groups and square-planar geometry for palladium(II). 1H N.m.r. and far-i.r. spectra, and molecular weight determinations are consistent with similar structures for the bromo and iodo-complexes.