Design of metal-organic NLO materials: complexes derived from pyridine-3,4-dicarboxylate

Abstract

Two new polymeric complexes, [Zn(pydc)]_n (1) and [Co(pydc)(H₂O)₂]_n·nH₂O (2) (pydc = pyridine-3,4-dicarboxylate), have been synthesized and characterized. Complex 1 crystallizes in an acentric space group Pna2₁ and consists of a 3D network with unsymmetrical pydc linkers arranged in a parallel mode. Complex 2 crystallizes in the centric space group P−1, in which pydc ligands link Co(II) metal ions to generate a 2D layer structure with (4,4) topology nets. The Kurtz powder measurement shows that 1 exhibits a powder SHG efficiency about 5 times higher than that of potassium dihydrogen phosphate (KDP) and represents the first NLO-active 3D coordination network with parallel arrangement of dipolar ligands.