Three New Zn(II)/Cd(II) Coordination Polymers Constructed with 2-Mercaptonicotinic Acid and 1,2-Di(4-pyridyl)ethylene: Syntheses and Structure Analysis

Three new Zn(II)/Cd(II) coordination polymers based on 2-mercaptonicotinic acid (H(2)mna) with 1,2-di(4-pyridyl)ethylene (dpe) introduced as a bridging ligand have been synthesized via hydrothermal method and structurally characterized by single-crystal X-ray diffraction as well as elemental analysis and IR. As reported in this paper, [Zn-2(dpe)(0.5)(mna)(2)] (1) can be classified as a two-dimensional layer structure in which the 1D chain composed of Zn(II) and mna ligands is bridged by dpe ligands, while the complex named [Zn-4(dpe)(4)(mna)(4)] (2) is a tetra-nuclear cluster compound. These two compounds are further extended to three-dimensional structures by hydrogen bonds along with C-H center dot center dot center dot pi and pi center dot center dot center dot pi interactions. Compound 3 with general formular [Cd-2(dpe)(0.5)(mna)(2)]center dot H2O belongs to a three-dimensional porous structure in which the 2D metal layers formed by the coordination of Cd(II) and mna ligands are connected with the bridging of dpe ligands.