Synthesis,Photophysical And Electrochemical Properties Of New Metal Rhenium Complexes

In this work,a series of 1,10-phenanthroline derivatives of planar rigid bidentate ligands and 2-methylimidazole ligand were employed as main and auxiliary ligands reacted with transition metal rhenium to afford 11 kinds of rhenium complexes.All complexes were characterized by nuclear magnetic resonance and infrared spectroscopy,and the photophysical and electrochemical properties of the complexes were studied by UV-Vis、 fluorescence and electrochemical tests.For all ligands and complexes,the relationship between chemical structure and properties was preliminary studied.This thesis mainly includes the following three parts:1.Four complexes,Re(mdpqn)Br(1),Re(dpqc)Br(2),Re(mdpqn)(imH)(3),Re(dpqc)(imH)(4),were synthesized by using main ligands 2-methylpyrazino [2,3-f] [1,10] phenanthroline(mdpqn)(L1),10,11,12,13-tetrahydrobipyridine [3,2-a:2’,3’-c] phenazine(dpqc)(L2),and auxiliary ligands 2-methylimidazole.The structures of L1,L2 and 1~4 were characterized by nuclear magnetic resonance spectroscopy.The results of their UV-Vis and fluorescence spectra showed that the structure of methyl and cyclohexane in the main ligand had no significant effect on the UV-Vis absorption and emission of the complexes,and the introduction of the auxiliary ligand 2-methylimidazole increase the UV-Vis absorption range of the complex to the maximum.The emission wavelength undergoes a blue shift of about 30 nm.Electrochemical studies show that the introduction of auxiliary ligands 2-methylimidazole changes the energy level structure of the complexes.2.Five complexes,Re(dppz)Br(5),Re(dppzBr)Br(6),Re(dppz-11-CooEt)Br(7),Re(dppz)(imH)(8),Re(dppz-11-CooEt)(imH)(9),were synthesized by using main ligands bispyridine [3,2-a:2’,3’-c] phenazine(dppz)(L3),dipyridylethyl [3,2-a:2’,3’-c] Phenazine-11-carboxylic acid ester(L4),12-bromopyrido [2’,3’:5,6] pyrazino [2,3-f] [1,10] phenanthroline(L5),and auxiliary ligands 2-methylimidazole.The structures of L3~5 and 5~9 were characterized by nuclear magnetic resonance spectroscopy,infrared spectroscopy.The results of their UV-Vis and fluorescence spectra show that the introduction of bromine and ethyl acetate groups in the main ligand both increased the UV-Vis absorption intensity of the complex in the low energy region and decreased the low energy emission intensity of the complex.The introduction of auxiliary ligands further increased the UV-Vis absorption intensity of the complex.The low-energy region of the complex 9 containing a carboxylic acid ester structure produces weaker emission,while the low-energy region of the complex 8 containing a bromine structure emits a blue shift in the wavelength.Electrochemical studies have shown that the introduction of different substituents of the main ligand and the introduction of the co-ligand can change the energy level structure of the complex.3.Two complexes,Re(dppp2)Br(10),Re(dppp3Br)Br(11)were synthesized by using main ligands pyrido [3’,4’:5,6] pyrazino [2,3-f] [1,10] phenanthroline(dppp3)(L6),12-bromopyrido [2’,3’:5,6] pyrazino [2,3-f] [1,10] phenanthroline(L7).The structures of L6,L7,10 and 11 were characterized by nuclear magnetic resonance spectroscopy.The results of their UV-Vis and fluorescence spectra showed that the introduction of pyridine and bromopyridine structures in the main ligand increased the UV-Vis absorption intensity of the complex in the low energy region and had no significant effect on the emission of the complex.Electrochemical studies showed that the introduction of pyridine and bromopyridine structures changed the energy level structure of the complex.