Cadmium(II) Complexes with Mixed cis- Epoxysuccinate and 2,2-Bipyridyl-Like Ligands: Syntheses, Crystal Structures, and Luminescent Properties

Two new CdII complexes, [Cd(ces)(phen)](infinity) (1) and {[Cd(ces)(bpy)(H2O)](H2O)}(2) (2), were prepared by slow solvent evaporation methods from mixtures of cis- epoxysuccinic acid and Cd(ClO4)(2)center dot 6H(2)O in the presence of phen or bpy co- ligand (ces = cisepoxysuccinate, phen = 1,10- phenanthroline, and bpy = 2,2'- bipyridine). Single- crystal X- ray diffraction analyses show that complex 1 has a one- dimensional (1D) helical chain that is further assembled into a two- dimensional (2D) sheet, and then an overall three- dimensional (3D) network by the interchain C-H center dot center dot center dot O hydrogen bonds. Complex 2 features a dinuclear structure, which is further interlinked into a 3D supramolecular network by the co- effects of intermolecular C- H center dot center dot center dot O and C-H center dot center dot center dot pi hydrogen bonds as well as p u u u p stacking interactions. The structural differences between 1 and 2 are attributable to the intervention of different 2,2'- bipyridyl- like co- ligands. Moreover, 1 and 2 exhibit intense solid- state luminescence at room temperature, which mainly originates from the intraligand pi-pi* transitions of aromatic co- ligands.