Five bis(imidazole)-based Coordination Polymers Tuned by Central Metal Ions and S-containing Dicarboxylates: Syntheses, Structures, and Properties

Abstract

Five new coordination polymers, namely [Zn(2-CMSN)(biim-4)] (1), [Co2(2-CMSN)2(biim-4)(H2O)4] (2), [Ni(2-CMSN)(biim-4)0.5(H2O)2] (3), [Cd(2-CMSN)(biim-4)0.5(H2O)2] (4), and [Cd(ADTZ)(biim-4)1.5]·5H2O (5), (2-H2CMSN = 2-carboxymethylsulfanyl nicotinic acid, H2ADTZ = 2,5-(S-acetic acid) dimercapto-1,3,4-thiadiazole, biim-4 = 1,1′-(1,4-butanediyl)bis(imidazole)) have been synthesised under hydrothermal conditions and structurally characterised by single-crystal X-ray diffraction analysis, infrared spectroscopy, elemental analysis, thermogravimetric analysis, and powder X-ray diffraction. Complex 1 shows a 2D undulated sheet, which is constructed from 1D meso-helical [Zn-(biim-4)]n chains and linear [Zn-(2-CMSN)]n chains. Complexes 2–4 exhibit a similar 2D (4,4) grid network constructed from zigzag [M-(2-CMSN)]n chains and linear [M-(biim-4)]n chains (M = CoII, NiII and CdII), which possesses a ‘4+2’ type six-membered ring. Complex 5 displays a 3D architecture derived from 2D Cd-(biim-4) layers and double ADTZ linkers with diamond-type 66 topology. The effects of the central metals and S-containing dicarboxylates on the structures of the title coordination polymers have been discussed. The luminescent properties of complexes 1, 4, and 5 have been studied. Complex 5 exhibits photocatalytic activity for dye degradation under ultraviolet light and good stability towards photocatalysis.