Syntheses, crystal structures and photophysical properties of a series of cadmium(II) coordination polymers

Three cadmium(II) coordination polymers [Cd(NA)(2)-(H2O)(2)]. (1), {[Cd(NA)(phen)(NO3)]center dot(H2O)(1/2)}(n) (2), {[Cd(NA)-(CH3C6H4COO)(H2O)(2)]center dot(CH3C6H4COOH)}(n) (3) (HNA = nicotinic; acid, phen = 1, 10-phenanthroline) have been synthesized by hydrothermal method. Their single-crystal structures were determined by X-ray diffractometry. The absorption, excitation and emission. spectra were investigated and all the complexes emit strong fluorescence: lambda(em)(max) = 544 nm (lambda(ex) = 492 nm), 1; k(max)(em) = 466 nm, 1 (lambda(em)(max) = 393 nm), 2; lambda(em)(max) = 430 nm (lambda(ex) = 313 nm), 3. At room temperature in the solid state the fluorescence lifetimes of the complexes were investigated and the relationships between the spectra were discussed as well as the connections of luminescence and crystal structures.