Metal-organic coordination polymers based on imidazolyl- and benzimidazolyl-containing 4,4′-bipy type ligands

摘要

Two new semirigid ligands 2,2′-bis(imidazol-1-ylmethyl)-4,4′- bis(4-pyridyl)biphenyl(L1) and 2,2′-bis(benzimidazol-1-ylmethyl)-4, 4′-bis(4-pyridyl)biphenyl(L2) were designed and synthesized. Six new coordination compounds, {Cd(L1)Br_2}_n (1), {Cd(L1)(1,2-bdc)(H_2O)×H_2O}_n (2), {Zn(L1) (1,3-bdc)×2.7H_2O}_n (3), {Co(L1)(1,3-bdc) ×H_2O}_n (4), (1,2-bdc = 1,2-benzenedicarboxylate, 1,3-bdc = 1,3-benzenedicarboxylate, {Cd(L2)_2(NO_3) _2×2H_2O}_n (5) and, [Ni(L2) _2(H_2O)_2](ClO_4)_2× 3H_2O (6) based on them were obtained and characterized by single-crystal X-ray diffraction methods. 1 is a 2D infinite spongy cushion-like network. In 2, two bridging 1,2-bdc anions chelate two neighboring Cd(II) atoms with their carboxylate groups to form a 1D double chain. 3 displays a 2D network in which the wavelike {Zn(1,3-bdc~(2-))}n chains are linked to each other by bidentate L1. 4 adopts a unique 3D framework, in which the coplanar {Co(1,3-bdc~(2-))}n chains are connected to each other through tridentate L1. 5 features a 1D double chain motif composed of a square bimetallic ring as the building block. 6 is mononuclear nickel complex. The photoluminescence properties of L1-L2, 1-3 and 5 were investigated, and all of them exhibit intense fluorescent emissions in the solid state at room temperature.