A stable second-order NLO and luminescent Cd(II) complex based on 6-hydroxynicotinic acid

Employing an unsymmetrical 6-hydroxynicotinic acid as a bridging ligand, we have prepared a new NLO-active two-dimensional cadmium coordination polymer [Cd8(nicO)8(phen)8 · (H2O)]n (1) (H2nicO = 6-hydroxynicotinic acid, phen = 1,10-phenanthroline) under hydrothermal condition. At room temperature, 1 shows strong fluorescent emission bands in the solid state and a SHG efficiency of about 8 times that of KDP (KH2PO4). On the basis of TG/DTA analyses, the structure is thermally stable up to 370 °C.