A noncentrosymmetric coordination polymer based on the benzophenone-3, 3′-disulfonyl-4,4′-dicarboxylate ligand exhibiting second-harmonic-generation responses

A 3D coordination polymer [CdK6(mu(2)-H2O)(2)(BODSDC)(2)(H2O)](n) (1) based on the novel benzophenone-3,3'-disulfonyl-4,4'-dicarboxylate (BODSDC4 similar to) ligand was synthesized and structurally characterized. The carboxylate and sulfonate groups of the organic ligands as well as the bridging water molecules connect the Cd2+ and K+ ions to produce a 2D layer, which is linked by the benzophenone moieties to give a 3D pillared framework. Compound 1 crystallizes in an acentric space group of Cc and has a large second-harmonic-generation (SHG) response of 1.3 times that of potassium dihydrogen phosphate (KDP) in the particle size of 25-210 mu m. Further SHG measurements revealed that the material is type-I phase-matchable. The observed SHG efficiency is associated with the unsymmetrical geometry of the organic ligand and the distorted coordination polyhedrons of metal centers.