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

Four new Cu(II) and Cd(II) coordination compounds, formulated as the {[Cu2(mu -cbpy)2(mu -cbpy)2(H2O)2]center dot 2H2O}n (1), {[Cu(mu -cbpy)2]center dot 2H2O}n (2), [Cu(cbpy)2(im)2]center dot 4H2O (3) and [Cd(mu -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 & ctdot;O, C- N & ctdot;pi and pi & ctdot;pi 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.