Syntheses and crystal structures of cadmium(II)X2-hexamethylenetetramine (X = Br−/I−/SCN−) coordination polymers having different dimensionality

Four new coordination polymers of cadmium(II) with hexamethylenetetramine (htm) have been synthesized and characterized by routine physicochemical techniques as well as by X-ray single crystal structure analysis. They are [CdBr(htm)(SCN)(H2O)2·CH3OH]n (1), [CdI(htm)(SCN)(H2O)2·0.5(CH3OH)]n (2), [Cd2(htm)3(SCN)4(H2O)]n·nH2O (3) and [Cd3Br6(htm)2(H2O)5·(htm)(H2O)6]n (4). Complexes 1, 2 and 3 exhibit 1D polymeric structure and complex 4 shows a 2D undulated layered arrangement, containing Cd6(htm)6 hexagonal units as building block, which extended to a 3D supramolecular architecture through hydrogen bonding. Thorough thermal investigation suggest that as far as the thermal stability of Cd(II)-htm bond is concerned it attains the maximum in complex 1 and minimum in complex 4. In case of complex 3 the thermal study inferred that CdS end product was obtained at ∼730 °C, whereas in case of other complexes the thermally stable end product remained unidentified. Solid state fluorescence study shows that all the complexes are luminescent at room temperature except complex 3.

Four new coordination polymers of cadmium(II)X2-hexamethylenetetramine system (X = Br/I/SCN) have been synthesized, characterized and their solid state thermal and luminescence studies were performed. Complexes 1, 2 and 3 exhibit 1D polymeric structure and complex 4 shows a 2D layer structure, which can be extended to a 3D supramolecular architecture through hydrogen bonding.Figure optionsDownload as PowerPoint slide