Reactions of benzyldiphenylphosphine with Pd(II) sources on silica gel

Depending on the conditions used, reactions of benzyldiphenylphosphine (HL1) with Na2PdCl4 on silica gel or with Pd(OAc)2 on the same absorbent followed by treatment with LiCl provide one or more of the four compounds: the cyclopalladated binuclear complex [(μ-Cl)PdL1]2 (1), cis and trans isomers of the coordination complex PdCl2(HL1)2 (3), the binuclear coordination complex [(μ-Cl)PdCl(HL1)]2 (4), and compound PdCl2(HL1)3 (5). The 56% yield of complex 1 achieved using the reaction with Na2PdCl4 and NaOAc on SiO2 is higher than that reported for the direct cyclopalladation of PBnPh2 with Pd(OAc)2 in AcOH. X-ray diffraction studies of the cyclopalladated dimer 1 and the coordination complex cis-3 are reported.