Synthesis, Characterization and Catalytic Study of a Novel Binuclear Paddle-wheel Palladium(II) Complex in the Mizoroki-Heck Reaction

A new binuclear paddle-wheel palladium(II) complex of [Pd2(μ-mtzt)4]dmgH2 (1) has been prepared by the treatment of PdCl2 in acetonitrile with mixture of 1-methyl-1H-1,2,3,4-tetrazole-5-thiol (Hmtzt) and dimethylglyoxime (dmgH2) in methanol. Resulted complex was characterized by elemental analysis (CHNS), IR, UV–Vis absorption, 1H NMR spectroscopy and its structure was determined with single-crystal X-ray diffraction. Single crystal analysis reveals that this complex has binuclear structure in a paddle-wheel fashion with Pd-Pd distances of 2.808(2)Å. Also, in this binuclear complex, each palladium(II) ion has a slightly distorted square-pyramidal coordination geometry with the two nitrogen and two sulfur atoms in equatorial positions from four bridges mtzt- ligands and the second palladium subunit in axial position. Catalytic potentiality of complex 1 is also exhibited in the Mizoroki–Heck coupling reactions between a range of aryl halides and olefins. The catalyst shows very much efficient reactivity in the Mizoroki–Heck reactions giving high yield of the coupling products.