Syntheses, characterization and fluorescent properties of two square pyramidal Cu (II) inorganic-organic hybrid polymers

Two copper(II) carboxylate polymers of formula [Cu2(OOCCH3)4(4,4′-bpy)]·DMF 1 and [Cu(OOCCH2COO)(DMF)] 2 (DMF=N,N-dimethylformamide) have been synthesized in mixed DMF-CH3OH-H2O solution and characterized by X-ray diffraction, FT-IR, UV-vis, EPR, XPS and fluorescence. The structure of 1 consists of a two-dimensional supramolecular layer constructed by intermolecular π-π interactions of the bipyridine rings from adjacent one-dimensional [Cu2(OOCCH3)4(4,4′-bpy)] chains. The space between the two neighboring layers is filled by the solvent DMF molecules and thus a sandwich-like supramolecular structure was formed. Polymer 2 contains a three-dimensional chiral framework constructed only by malonate ligand with syn-anti and anti-anti coordination modes. The fluorescent properties of 1 and 2 have been measured showing strong fluorescent emissions at room temperature.