Syntheses,Structures And Properties Of Keggin-Type Polyoxometalate Hybrid Compounds Constructed By N-Heterocyclic Ligands

Polyoxometalate-based hybrid compounds constructed by N-heterocyclic ligands,that is,the organic components contained in the compounds are used to modify the polyoxometalates,obtaining polyoxometalates with various structural types and excellent properties are now used in catalysis,materials,and other fields.In this paper,ten kinds of Keggin-type organic-inorganic hybrid compounds were successfully obtained with different kinds of N-heterocyclic ligands,The single crystal structures of the compounds were determined and a series of characterizations such as infrared spectroscopy,X-ray powder diffraction,and thermal weight loss analysis were carried out.At the same time,the fluorescent properties,electrochemical properties,magnetic properties,and photocatalytic degradation of organic dyes of some compounds were investigated.1.Using 2-phenyl-lH-phenanthro[9,10-d]imidazole(ppi)organic ligand,four Keggin-type Poly oxometalate hybrid compounds were synthesized by mixed solvent heat and conventional aqueous solution methods.Compounds 1-3 all are formed three-dimensional supramolecular structure by hydrogen bonds and π-π stack,Compound 4 is formed a two-dimensional layered structure by hydrogen bonds.The photodegradation of organic dye(RhB)by the compounds 1-4 showed certain catalytic activity.(Hppi)5[BW12O40]·3H2O(1)(Hppi)4[SiW12O40]·6H2O(2)(Hppi)3[PMo12O40]·(ppi)H2O(3)(Hppi)3[PW12O40]·5H2O(4)2.Using 2,4,5-triphenylimidazole(tpi)organic ligand,compounds 5-8 are successfully synthesized by mixed solvent heat and conventional aqueous solution methods.Compound 5 shows three-dimensional supramolecular structure by hydrogen bond.Compounds 6-8 exhibit two-dimensional layered structure by hydrogen bond.Dye decolorization experiments show that compounds 7and 8 have a certain decolorization ability to the organic dye methylene blue(MB).(Htpi)5[BW12O40]·2H2O(5)(Htpi)4[SiW12O40]·2H2O(6)(Htpi)3[PMo12O40]·(tpi)·6H2O(7)(Htpi)3[PW12O40]·1.5 H2O(8)3.Using pyrido[3’,4‘:5,6]pyrazino[2,3-f][1,10]phenanthroline(ppy)and 1H-imidazo[4,5-f][1,10]-phenanthroline(ip),two Keggin-type Polyoxometalate hybrid compounds containing transition metal Cu were obtained by hydrothermal synthesis.Compounds 9 and 10 are all one-dimensional chain structures.Electrochemical performance studies show that compounds 9 and 10 exhibit good electrocatalytic ability for H2O2 reduction.Magnetic measurements show that compounds 9 and 10 exhibit antiferromagnetic behavior.[Cu2(H2O)4(ppy)2(SiW12O40)]·2H2O(9)[Cu2(H2O)2(ip)2(SiW12O40)]·7H2O(10)...