Synthesis, coordination, and spectroscopic properties of 2,2 '-bipyridyldimesitylpalladium(II) and 6-mesityl-2,2 '-bipyridyldimesitylpalladium(II)

The synthetic route to the dimesitylpalladium(II) complex [(bpy)PdMes(2)] ( 1) (Mes = mesityl = 2,4,6-trimethyl phenyl) does not only give the desired compound but also the 6-mesityl-2,2'bipyridyldimesitylpalladium [(6-Mes-bpy )-PdMes(2)] (2) complex and the free ligand 6,6'-dimesityl-2,2'-bipyridine in reasonable yields. Single crystals of 2 were examined by X-Ray diffracti on. The compound reveals a sterically crowded molecular structure. An intra molecular pi-stacking interaction was found between the mesityl substituent on the bipyridine ligand and the adjacent mesityl ligand. The electrochemi cal behaviour of 1 and 2 together with a related compound was examined at v arious temperatures showing two reversible reduction reactions and reversib le one-electron oxidation steps at low temperatures. The latter are assigne d to Pd-II/Pd-III couples.