Synthesis And Photocatalytic Properties Of Bipyridylium Complexes Containing Pyrazole,Pyridazine And Pyrimidinyl Ligands

Bipyridine ruthenium complexes are widely used in electrochemiluminescence and dye-sensitized solar cells due to their excellent photophysical properties.In this thesis,three ligands were designed to synthesize a series of bipyridine ruthenium complexes,and their photocatalytic,redox and photocatalytic properties were discussed.?1?Two pyrazole-trifluoromethyl ligands L1*H₂ and L2*H were synthesized,and the two ligands were refluxed with cis-?bpy?₂RuCl₂·2H₂O and cis-?dmb?₂RuCl₂·2H₂O in EtOH/H₂O?V:V=1:1?to obtain four bipyridylium hydrazines complexes:[?bpy?₂Ru?L1?]?1??[?dmb?₂Ru?L1?]?2??[?bpy?₂Ru?L2?]?PF₆??3??[?dmb?₂Ru?L2?]?PF₆??4?,the crystal structures of 1,3 and 4 were determined by single crystal X-ray diffraction analysis,and 1⁴ were characterized by NMR spectroscopy.The photophysical properties of these complexes were studied.It was found that 1 has the highest fluorescence intensity.Studies on the electrochemical properties of 1⁴ show that the stronger the electron-withdrawing ability of the series of complexes,the higher the oxidation peak potential and the stronger the oxidation.?2?Six pyrazolyl-pyridazine ligands L3^L8 were synthesized,and refluxing the six ligands with cis-?bpy?₂RuCl₂·2H₂O in EtOH to obtain[?bpy?₂Ru?L3?]?PF₆?₂?5??[?bpy?₂Ru?L4?]?PF₆?₂?6??[?bpy?₂Ru?L5?]?PF₆?₂?7??[?bpy?₂Ru?L6?]?PF₆?₂?8??[?bpy?₂Ru?L7?]?PF₆?₂?9??[?bpy?₂Ru?L8?]?PF₆?₂?10?,and the crystal structures of 5,6and 7 were determined by single crystal X-ray diffraction analysis,the ligand L3^L8and the complex 5¹0 were characterized by NMR spectroscopy.The UV visible absorption of these complexes show that the blue shift of 5 is most obvious,because the corresponding ligand L3 contains four electron-donating groups-CH₃,the stronger the electron donating ability,the more obvious the blue shift.The electrochemical test results of the complexes 5¹0 showed that the oxidation peak potentials of the six complexes were all around 1.5V.?3?Five pyrazolyl-pyrimidine ligands L9^L13 were designed and synthesized,and these ligands were separately refluxed with cis-?bpy?₂RuCl₂·2H₂O in EtOH to obtain five corresponding complexes:[?bpy?₂Ru?L9?]?PF₆?₂?11??[?bpy?₂Ru?L10?]?PF₆?₂?12??[?bpy?₂Ru?L11?]?PF₆?₂?13??[?bpy?₂Ru?L12?]?PF₆?₂?14??[?bpy?₂Ru?L13?]?PF₆?₂?15?,and L13 were characterized by NMR.The photophysical properties of 11¹5 were studied,and the results show that 11 has the strongest electron-absorbing ability and the strongest luminescence intensity.The MLCT of the ultraviolet spectrum has a relatively large maximum wavelength of 436 nm and the blue shift is the smallest.The electrochemical results of 11¹5 show that the oxidation peak potential of 11 is the largest?Epa=1.648V?,and the oxidation is strong.?4?Three bipyridylium ruthenium complexes 1,7 and 10 were selected as photosensitizers to study the effects of different photosensitizers on hydrogen production by photolysis of water,the experimental results show that the catalytic effects of the three photosensitizers are similar.The effects of different types of sacrificial agents and sacrificial agents on hydrogen production by photolysis of water were studied.The results showed that the hydrogen production was the highest under the condition that the sacrificial agent was triethylamine and the dosage was 5 mL.