Construction and second-order nonlinear optical properties of two 1D zigzag chains with crisscross and parallel arrangements

Two noncentrosymmetric d(10) metal centered coordination polymers with formula [Zn(PTA)Cl-2] . H2O (1) and [Hg-3(PTA)(3)Cl-6] (2) have been successfully prepared by the reaction of rigid non-centrosymmetric ligand 3,5-dimethyl-N-(pyridin-4-ylmethylene)-4H-1,2,4-triazole-4-amine (PTA) and corresponding metal salts ZnCl2 and HgCl2. Both 1 and 2 feature acentric 1D zigzag chain arrangements, in which each chain is composed of linear 2-connected PTA ligands and V-shaped 2-connected metal nodes Zn(II) or Hg(II). Complex 1 possesses C-2 symmetric eqitlateral 1D zigzag chain structure and corresponding crisscross array. In contrast with 1, 2 displays dissymmetric ineqitlateral 1D zigzag chain structure and common parallel arrangement. Being their acentric essence as well as colorless and transparent merits, the preliminary powder NLO properties of 1 and 2 were invesigated in solid-state. The results indicated that the SHG intensities of 1 and 2 are about 1 and o.5 times that of commercial KDP.