Crystal Structure of Dimeric Units Cd-2(ncpo)(2)(phen)(2)(H2O)(2) Constructed by Flexible Dicarboxylic Acid with Fluorescent Emission

A dimeric coordination complex Cd-2(nCPO)(2)(phen)(2)(H2O)(2) was constructed by a flexible dicarboxylic acid, 2-nitro-4-carboxylphenoxyacetic acid. Its crystal structure was determined by X-ray single-crystal diffraction analysis. The crystal is of monoclinic system, space group P2(1)/n with a = 17.2616(3), b = 12.7460(2), c = 18.4041(3) angstrom, beta= 94.432(1)degrees, C42H30Cd2N6O16, M-r = 1099.52, V = 4037.09(12) angstrom(3), D-c = 1.809 g/cm(3), F(000) = 2192, mu = 1.139 cm(-1) and Z = 4. The final R = 0.0218 and wR = 0.0703 for 8288 observed reflections with I > 2 sigma(I). There are two crystallographically independent but structurally very similar molecules in the unit cell of the title complex. It is noticeable that the ligand ncpo(2-) displays a good flexibility, demonstrating different modes from the rigid ligands. The luminescence property has been investigated, which shows photoluminescence at 465, 490 and 574 nm upon excitation at 320 nm in the solid state at room temperature.