Synthesis and spectroscopic properties of four metal complexes with bipyridinium-based ligand

A series of new transitional metal charge-transfer (CT) complexes with a bipyridinium-based ligand [M(PrBpy)2(SCN)4] (M = Cd(II), Ni(II), Co(II)) and [Cu(PrBpy)(SCN)3(H2O)] (PrBpyCl = N-(2-pyrazinyl)-4,4′-bipyridinium chloride) have been obtained and determined by X-ray diffraction, FT-IR and elemental analysis. The CT absorption bands of the four compounds were observed by diffuse reflection spectroscopy and a photo-induced electron transfer occurs in methanol solution upon light irradiation.