Syntheses, crystal structures and photoluminescence properties of three novel organically bonded indium selenates or selenites

Three new organically bonded indium(III) selenates or selenites, namely, In2(2,2′-bipy)2(SeO4)3(H2O)2·2H2O (1), In2(2,2′-bipy)2(SeO4)(C2O4)2·0.5H2O (2) and In2(2,2′-bipy)2(SeO3)2(C2O4) (3) (2,2′-bipy=2,2′-bipyridine) have been synthesized by hydro/solvothermal reactions by using the in situ ligand synthesis technique (2 and 3) and structurally characterized. The structure of compound 1 features a dimer composed of two InO4N2 octahedra bridged by three SeO4 tetrahedra via cornering sharing. The structure of compound 2 shows a 2D inorganic–organic hybrid layer in which the indium (III) ions are bridged by both selenate and oxalate anions, whereas the structure of compound 3 possesses a 2D inorganic–organic hybrid layer composed of the indium (III) ions interconnected by both selenite and oxalate anions. The adjacent layers are further interconnected via π…π interactions between the bipy ligands. Compound 1 displays an intra-ligand luminescent emission band at λmax=360 nm whereas compounds 2 and 3 both exhibit intra-ligand luminescent emission bands at λmax=389 nm.