Catalytic Activity Of A Diruthenium(?) Complex For Water Oxidation And Its Assembly Properties

As an important step in the process of photosynthesis,the water oxidation provides not only electrons and protons to fix carbon dioxide,but also oxygen for the biosphere.In artificial photosynthesis process,the development of highly efficient catalyst towards water oxidation is an important research topic and what get hydrogen to solve the problem of environment.Transition metal complexes with rich optical,redox and catalytic properties have attracted much attention from researchers.In particular,some ruthenium complexes,showing good catalytic activities to some reactions,have been the focuses of many research works.In this work,we investigated the catalytic activity of a binuclear ruthenium complex[Ru2(?-O)(?-OOCCH3)2(2,2'-bpy)2(H2O)2](PF)2(1)(2,2,-bpy=2,2,-pyridine)for the water oxidation reaction,and then used(1)as a building block to construct heteronuclear complex systems by reacting with dinuclear iron complexes.The research work includes three parts below:1.In the solution of HClO4 with different oxidant {Ce(NH4)2(NO3)6 or KHSO5},the catalytic activities of complex(1)for water oxidation under different pH and concentrations have been investigated.When Ce(NH4)2(NO3)6 was used as the oxidant,at pH=0.60?C{(1)}=0.20 mmol.L-1?C(Oxidant)=160 mmol.L-1,(1)showed the best catalytic activity with a turnover number(TON)of 7.38.When KHSO5 was used as the oxidant,at pH=1.20?C{(1)}=0.20 mmol.L-1?C(oxidant)=160 mmol.L-1,(1)showed the best catalytic activity with a turnover number(TON)of 9.66.2.Electrochemical catalytic activity of(1)was measured in homogeneous and heterogeneous conditions.In the homogeneous solution system,the complexes(1)showed catalytic activities with a Faraday efficiency of 76%.When loaded on the ITO electrode,(1)showed catalytic activities with a Faraday efficiency of 91.7%.3.Complex(1)was used to react with dinuclear iron complexes to prepare four hetero-nuclear complexes {[Ru2(?-O)(?-OOCCH3)2(2,2'-bpy)2(4,4'-bpy)2Fe2O(X)2]6+ {4,4'-bpy=4,4'-bipyridine?X=1,10-phenanthroline(6)or 4,4'-dimethyl-2,2'-bipyridine(7)};[Ru2(?-O)(?-OOCCH3)2(2,2'-bpy)2(C12H12N2)2Fe2O(X)4]6+ {C12H12N2= 1,2-bis(4-pyridy l)ethane?X= 1,10-phenanthroline or 4,4,-dimethyl-2,2,-bipyridine)} which have been characterized by UV-vis?ESI-MS and 1HNMR.Its shows that:The binuclear ruthenium and the binuclear iron units are linked by different bridging ligands(4,4'-pyridine?1,2-di(4-pyridyl)ethane what made the complexes skeleton characteristic absorption peak shift.