Synthesis, Crystal Structure and Photoluminescence of a 2D Two-fold Interpenetrating Cd(II) Coordination Polymer Based on a Flexible Reduced Schiff Base Ligand

By the reaction of cadmium chloride with a reduced Schiff base ligand (H2L = N-(4-carboxybenzyl)-glycine), a novel Cd(II) compound [Cd(HL)(2)]center dot 4H(2)O (1) has been obtained. Single-crystal X-ray diffraction analysis reveals that it crystallizes in orthorhombic, space group Pbcn with a = 13.9788(8), b = 24.4204(14), c = 13.9580(8) angstrom, V = 4764.8(5) angstrom(3), Z = 8, M-r = 600.84, D-c = 1.675 g/cm(3), mu = 0.983 mm(-1), F(000) = 2448, S = 1.084, R = 0.0806 and wR = 0.1705 (I > 2 sigma(I)). It displays a 2D two-fold interpenetrating structure. The Cd(II) ions are six-coordinated. The cross-linkage of Cd(II) ions by the bridge of HL anions results in a [Cd(HL)(2)] layer. Every two [Cd(HL)(2)](n) layers are penetrated with each other, resulting in a two-fold interpenetrating double-layer structure by pi-pi. stacking interactions and hydrogen bonds. Such double-layers are further linked by hydrogen bonds into a supramolecular structure. Photoluminescent investigation shows that compound 1 displays strong emission in the purple region.