Preparation Of Osmium(Ⅱ) Complexes Based On Triazole And Applications For Photocatalytic Oxidation Of Benzylamine

In this thesis, we describe the synthesis and characterization of five Os(Ⅱ) com-plexes(i.e., [Os(fptz)2(PPhMe2)2](1, fptzH=3-trifluoromethyl-5-pyridyl-],2,4-triazole), [Os(fptz)2(CO)(L1)](2, L1=PPh3; 3, L,=pyridine), [Os(dtbbpy)(dttz)(PPhMe2)2](4, dtbbpy=4,4’-di-tert-butyl-2,2’-bipyridine, dttzH2=5,5’-di(trifluoromethyl)-3,3’-di-1,2,4-triazole, [Os(dtbbpy)(dttz)PPhMe2CO](5). Os(Ⅱ) complexes was used phosphine ligands or pyridyl as an auxiliary ligand. The target product was purified by silica gel column and recrystallization. The structure was characterized by 1H NMR, ESI-MS and X-ray single crystal diffraction. The optical properties were characterized by using ultraviolet visible spectrophotometer, fluorescence spectrometer, transient fluorescence spectroscopy and infrared spectroscopy. It shows that complexes does not contain carbonyl have a good absorption in visible region. Redox potential shows that complex 1 has a potentially excellent photosensitizer characteristics; The photophysical and electrochemical properties were measured and discussed using the results of density functional theory (DFT) calculations.Os(Ⅱ) complexes have been successfully utilized as good photocatalysts to promote aerobic oxidative coupling of amines to imines with molecular oxygen in air as a green oxidant. The use of complex 1 leads to the most effective catalysis for the oxidative coupling of benzylamine with molecular O2(air) as the oxidant because of the complex’s strong absorption of visible light and longlived triplet state. The application of a low catalyst loading of complex 1 to the oxidative coupling of a wide range of amines affords the corresponding imines efficiently and selectively in most cases. The reaction mechanism was investigated via relevant control and quenching experiments. The results indicated that the reaction occurs via an active 1O2 involved pathway. The 1O2-generating ability of complex 1 as a photosensitizer was evaluated using 9,10-dimethylanthracene (DMA) as a chemical trap for 1O2...