Polymeric Zn(II) and Cd(II) Sulfates with Bipyridine and Dioxime Ligands: Supramolecular Isomerism, Chirality, and Luminescence

The interaction of zinc(II) or cadmium(II) sulfate with 4,4′-bipyridine (bpy) or 4,4′-bipyridinethane (bpe) in the presence of 1,2-cyclohexanedionedioxime (NioxH2) resulted in four novel polymeric compounds with the compositions {[Zn(H2O)6][Zn(SO4)2(H2O)2(bpy)][Zn(SO4)(H2O)3(bpy)]}∞ (1), {[Zn(SO4)(NioxH2)(bpy)]·0.5H2O·DMF}∞ (DMF = N,N-dimethylformamide) (2), [Zn(SO4)(NioxH2)(bpe)]∞ (3), and [Cd(SO4)(NioxH2)(bpe)]∞ (4). Compounds were characterized by spectroscopic techniques and single crystal X-ray method. The chiral layer coordination polymer is the robust structural motif in 2–4. Although compounds 3 and 4 were isolated in the same crystallization conditions, the layers of opposite chirality constitute the achiral (3), and the layers of the same chirality result in chiral (4) architectures. All materials display blue luminescence upon excitation with ultraviolet light.