Supramolecular architectures of cadmium(II) built of 2,2'-biimmidazole and bifunctional carboxylates: Syntheses, crystal structure and properties

摘要

A series of four new supramolecular complexes of cadmium(II), {[CdBr(H(2)biim)(PyCO2)(H2O)](H2O)}infinity(1) (H(2)biim = 2,2'-biimidazole, PyCO2 = isonicotinate), [Cd(H(2)biim)(2)(HBDC)(2)](2) (H2BDC = terephthalic acid), [Cd(H(2)biim)(2)(H2O)(2)](BDC) (3) and [Cd(H(2)biim)(2) (H2O)(2)](PyCO2)(2) (.) 4H(2)O (4) have been prepared and characterized by X-ray crystallography, IR, fluorescence spectra and thermogravimetric analysis. Compound I exhibits an infinite chain-like structure through bridging isonicotinate. Strong interchain hydrogen bonds between isonicotinate and H2biim result in the robust 2-D sheet Structure, responsible for the insolubility. The similar hydrogen bonds between H(2)biim and the coordinated 1,4-bdc and complementary hydrogen bonds between monoprotonated bdc are responsible for the robust 2-D layered structure of 2 that is insoluble in aqueous solution. 1,4-Bdc becomes uncoordinated in the soluble complex 3, although it has hydrogen bonded 2-D structure as well. (c) 2005 Elsevier B.V. All rights reserved.