Anion effects on crystal structures of Cd ^II complexes containing 2,2'-bipyridine: Photoluminescence and catalytic reactivity

Anion effects on structures of Cd ^II complexes containing 2,2'-bipyridine (2,2'-bpy) ligands have been studied, and compared with ZnII-(2,2'-bpy) complexes. For each anion, different structures have been obtained in both ZnII-(2,2'-bpy) and Cd ^II-(2,2'-bpy). Polymeric structures of Cd ^II-2,2'-bpy complexes can be produced by hydrogen bonding interactions as shown in ZnII-2,2'-bpy complexes. In addition, the bigger size of a Cd ^II ion gives higher coordination numbers forming variety of structures, and it makes that chlorides can act as bridging ligands to form a one-dimensional structure. The compound 5 catalyzed efficiently the transesterification of a variety of esters with methanol, while the rest of the compounds have displayed very slow conversions. In addition, the emission bands of complexes 1, 2, 4, and 6 are blue-shifted compared to the corresponding ligand 2,2'-bpy, whereas 3 and 5 showed the similar emission observed for the ligand.