Palladium(II) Complexes with Benzoxazol-2-ylidene Ligands: Crystal Structures of trans-Chloro(benzoxazol-2-ylidene)- bis(triphenylphosphine)palladium(II) Chloride and cis-Diiodo(benzoxazol-2-ylidene)(triphenylphosphine)palladium(II)

Abstract

The palladium(II) complexes trans-[PdCl(L)(PPh 3 ) 2 ]Cl, 5, and cis-[PdI 2 (L)PPh 3 ], 7, (L = benzoxazol- 2-ylidene) have been synthesized by treatment of the complexes trans-[PdX 2 (PPh 3 ) 2 ] (4: X = Cl, 6: X = 1) with 2-(trimethylsiloxy)pheny1 isocyanide 1, and subsequent hydrolysis of the Si-O bond. The crystal structures of 5 and 7*CH 2 Cl 2 were established by X-ray diffraction. NMR and IR studies indicate, that the unexpected cis-configuration of 7 obtained from trans-[PdI 2 (PPh 3 ) 2 ] is not the result of a solution equilibrium between the cis- and the trans-isomers.