Synthesis and characterization of four coordination compounds with 3,5-dicarboxy-1-(3-cyanobenzyl)pyridin-1-ium bromide and investigation of the photoreaction of 2D cadmium(II) compound

Abstract

Four new Cu(II) and Cd(II) coordination compounds, formulated as the {[Cu2(μ-cbpy)2(μ-cbpy)2(H2O)2]⋅2H2O}n (1), {[Cu(μ-cbpy)2]⋅2H2O}n (2), [Cu(cbpy)2(im)2]⋅4H2O (3) and [Cd(μ-cbpy)2(H2O)2]n (4) (H2cbpyBr: 3,5-dicarboxy-1-(3-cyanobenzyl)pyridin-1-ium bromide, im: imidazole) were synthesized and characterized by elemental analysis, IR spectroscopy and single crystal X-ray diffraction techniques. Structural analysis indicates that compounds 1, 2 and 4 exhibit 2D layer structures which are are further linked into 3D supramolecular architectures through hydrogen bonding, C−H⋯O, C−N⋯π and π⋯π interactions whereas compound 3 exhibits mononuclear structure. The photoreaction property of compound 4 was investigated and it exhibited color change from pale yellow to dark yellow under 365 nm UV lamp. The thermal properties and phase purities of compounds 1–4 were investigated by thermal analyses (TG, DTA and DTA) and powder X-ray diffraction (PXRD) techniques.