Study On Synthesis And Properties Of Transition Metal Rhenium Diimide Complex

Metal rhenium(Re)complexes have attracted many attention for their relatively good chemical stability and excellent photochemical properties.In this work,eight different imidazophenanthroline ligands were designed and synthesized by using 1,10-phenanthroline and benzaldehyde derivatives as raw materials.The further addition of aniline under nitrogen protection provide two aryl substituted imidazophenanthroline ligands.The newly obtained ten ligands were employed to reacted with the penta-carbonyl rhenium bromide and ten transition metal rhenium complexes were obtained.After that,the structures and properties of these compounds were studied carefully.The main content of the work can be divide into three parts:1.Using 1,10-phenanthroline and benzaldehyde derivatives as raw materials,three kinds of imidazophenanthroline electron-donating ligands,namely L1?L3,were synthesized.Three new transition metal rhenium complexes were synthesized with L1?L3 as ligands,namely 1?3.The structures and properties of the ligands and complexes were characterized by IR,UV-Vis,NMR and electrochemistry.The maximum emission peak of ligand L1 in dichloromethane solution is around 377 nm,and the maximum emission peaks of ligands L2 and L3 are around 421 nm,which is red-shifted by 44 nm compared with L1 The electron cloud density of the ligand is reduced.At the same time,these emissions are attributed to the occurrence of an electronic transition in the ligand.The maximum peak of the three complexes in the dichloromethane appeared at about 565 nm,which is a relatively obvious orange-yellow light emission and can be attribute to the charge transition from metal to ligand.The structure of molecules was optimized using density functional theory(DFT),and the absorption and emission spectra of molecules were studied using time-dependent density functional theory(TD-DFT).2.Five different imidazophenanthroline electron-withdrawing ligands,namely L4-L8,were synthesized from different benzaldehyde derivatives.The reaction of these five ligands with rhenium bromide pentacarbonyl gave five different complexes,namely 4?8.The structures and properties of these ligands and complexes were characterized by IR,UV-Vis,NMR and electrochemical methods.The emission spectra of the ligands in dichloromethane shows that the maximum emission peaks of the five ligands are around 415 nm,which is attribute to the electronic transition of ???*in the ligand.It can be seen from the emission spectrum of the complex dichloromethane that the complexes are all orange-yellow light emission,which is attributed to the charge transition between the metal and the ligand.At the same time,it was found that the introduction of fluorine atoms,chlorine atoms,and bromine atoms makes the complex The emission spectrum of the object has a blue shift.The structure of molecules was optimized using density functional theory(DFT),and the absorption and emission spectra of molecules were studied using time-dependent density functional theory(TD-DFT).3.Based on above work,aniline was added under the protection of nitrogen to obtain two new ligands,namely L9 and L10.Then,two transition metal rhenium complexes were obtained,namely 9?10.The emission spectrum of the ligand in dichloromethane shows that the maximum emission wavelength of the two ligands is about 425 nm,which is because the electronic transition of ???in the ligand.The emission spectrum of the complex dichloromethane depicted that the maximum emission wavelength is about 565 nm,which is attribute to the charge transition between the metal and the ligand.The structure of molecules was optimized using density functional theory(DFT),and the absorption and emission spectra of molecules were studied using time-dependent density functional theory(TD-DFT).