Mixed ligand palladium(II) complexes of oxalate and malonate with vitamin-B6 molecules:: synthesis, crystal structure and kinetics

The synthesis of six mononuclear palladium complexes of general formula [Pd(ox)/(mal)L-2] and [Pd(ox)/(mal)L'] (ox = oxalate, mal = malonate, both L and L' are vitamin-B-6 molecules (I), L = pyridoxine, pyridoxal and L' = pyridoxamine) has been achieved. The structures of these compounds were established by elemental analysis, i.r. and C-13-n.m.r. [Pd(oxalate)(pyridoxine)(2)] was analyzed by single crystal X-ray diffraction. It exhibits square planar coordination with bond lengths 2.015 (2) Angstrom for Pd-N and 2.010 (2) Angstrom for Pd-O. The interaction of [Pd(ox)(2)](2-) and [Pd(mal)(2)](2-) with L has been followed kinetically in order to look into the nature of products and the mechanism of formation under the conditions [Pd-II-chelate] >> [L] and [L'].