Two Gold (Ⅰ) Complexes Derived From P-s Hybrid Ligands: Synthesis And Catalytic Performance In The Photodegradation Of Aromatic Pollutants

In recent years, Au-containing materials have received much attention for their photocatalysis applications in organic reactions, hydrogen production by water splitting and the conversion of environmental pollutants. In the case of the conversion of pollutants, the known photocatalysts are usually Au nono-materials, but rarely Au coordination compounds up to now. In this thesis, a P-S hybrid ligand N,N-bis(diphenylphosphanylmethyl)-amino-thiocarbamide(dppatc) was selected to react with HAu Cl4?4H2O. Two new complexes were separated and structurally determined. Their catalytic activities toward the photodegradation of nitroaromatics and azo pollutants in aqueous solutions were also investigated. The main contents of this thesis are described as follows:(1) A minireview has made on the applications of Au-containing materials as photocatalysts in organic reactions, hydrogen production by water splitting and the conversion of environmental pollutants. Au coordination compounds are used as photocatalysts in organic coupling reactions, while Au nanoparticles and Au nanocomposites have been widely used as photocatalysts in the organic oxidation reactions, hydrogen generation by water splitting and the conversion of environmental pollutants. This indicates that Au-containing materials have good absorption toward light and can be used as photocatalysts.(2) Solvothermal reactions of HAu Cl4?4H2O with dppatc at 80 °C and 115 °C produced two Au-P-S complexes, [Au2(dppatc)2]Cl2(1) and [Au2(dppmt)2]n(2)(dppmt H =(diphenylphosphino)methanethiol), respectively. 1 and 2 were characterized by elemental analyses, IR and UV-vis spectra, 1H NMR,31 P NMR,thermal-gravity analyses, powder X-ray diffraction and single crystal X-ray diffraction analysis. Compound 1 contains a dinuclear [Au2(dppatc)2]2+ dication. While compound 2 has a one dimensional formed by Au…Au interactions, in which the ligand dppmt was in-situ generated from dppatc.(3) The catalytic activities of compounds 1 and 2 were investigated by using them as the catalysts in the photodegradation of nitrobenzene, p-nitrophenol and 2,4-dinitrophenol in aqueous solutions. The degradation reactions followed the zero-order kinetic model, in which three nitroaromatics could be decomposed into CO2 and H2 O in 92-96% yields. Compound 1 exhibited a better photocatalytic activity than compound 2. Both compounds were stable during the photodegradation when there have no obvious efficiency decay occurred after 5 cycles. The mechanism of the catalytic photodegradation is proposed to be the ·OH radical mediated route.(4) The catalytic activities of compounds 1 and 2 were evaluated by employing them as the catalysts in the photodegradation of a group of azo dyes and p-aminoazobenzene. These azo dyes can be fully oxidized into CO2 and H2 O within 40-180 min. The catalytic photodegradation reaction was also subjected to zero-order kinetics. The yield of CO2 generated from the reaction was 88-98%. The fact that most of the nitrogen and sulfur atoms had been converted into NH4+, NO3- and SO42- proved that the azo dyes have been fully oxidized into harmless inorganic ions.