A series of five divalent zinc and cadmium coordination polymers based on a new bifunctional ligand: syntheses, crystal structures, and properties

Abstract

A series of five coordination polymers, namely, [Zn(L)₂(H₂O)₂]·3H₂O (1), [Cd(L)₂(H₂O)₂]·3H₂O (2), [Zn(L)Cl]·2H₂O (3), [Cd(L)Cl] (4), [Cd(L)(NDC)_0.5] (5) (HL = 3,5-bis(imidazol-1-ylmethyl)benzoic acid hydrochloride, H₂NDC = naphthalene-1,4-dicarboxylic acid), have been hydrothermally synthesized through the reaction of HL with divalent zinc and cadmium salts, and their structures have been characterized. Due to various coordination modes and conformations of the versatile 3,5-bis(imidazol-1-ylmethyl)benzoic acid ligand, these complexes exhibit structural and dimensional diversity. Complexes 1 and 2 are isostructural and exhibit a meso-helical chain structure, and the chains are further connected through the hydrogen bonds to generate a 3D supramolecular network. Complex 3 features a 2D network structure with (6,3) topology. Complex 4 displays a 2-fold interpenetrating ant topological net with the point (Schläfli) symbol of {4².6}₂{4⁴.6².8⁸.10}. Complex 5 shows a (3,8)-connected tfz-d framework (4³)₂(4⁶·6¹⁸·8⁴) topology. The thermal stability, luminescent properties and powder X-ray diffraction (PXRD) were investigated.