A ternary tetracoordinated PdII complex with metformin and dipicolinate: Synthesis, characterization and crystal structure

A proton transfer compound L, (MetH)2(dipic), (dipicH2 = 2,6-pyridinedicarboxylic acid and Met = Metformin (N,N-dimethylebiguanidine), was synthesized and characterized by IR, 1H and 13C NMR spectroscopy. The reaction of L with PdCl2 in water results in the formation of novel tetracoordinated PdII complex [Pd(dipic)(Met)]·2H2O indicating the participation of both dipic2− and Met as chelating ligands. This complex was characterized by single crystal X-ray analysis. The crystal system is monoclinic with space group P21/c. The unit cell dimensions for PdII complex 1 is a = 8.8619(14) Å, b = 9.5072(9) Å, c = 19.153(3) Å.

► We present an approach to make a ternary tetracoordinated PdII complex.
► This complex involves metformine and dipicolinic acid, the known compounds in diabets treatment researches, as ligands.
► The dipicolinic acid is coordinated to the metal in a bidentate manner.
► Dipicolinic acid in most of the corresponding metal complexes behaves as a tridentate ligand.
► Synthesis of such vanadium complexes may improve the potential and possible synergy effect for the diabets treatment.