Synthesis,Characterization And Quantitative Calculation Of Terpyridine Ligands And Metal Complexes

In this thesis,the following research contents are reported:1.Based on the study of 8 substituted 4'-phenyl-2,2,:6',2"-terpyridine compounds in our group(-H(L1),-OCH3(L2),-S02CH3(L3),-CN(L4),-CH3(L5),-Ph(L6),-I(L7),-p-PhCH3(L8)).Three new 4'-(4-substituted)-phenyl-2,2':6',2"-terpyridine compounds(-COOH(L9),-F(L10),-OH(L11))were synthesized.After characterization,the fluorescence properties of these compounds were measured.The results show that the maximum fluorescence peaks of the compounds occur to red shift in comparison with L1 when the substituent on the benzene ring is the electron donor group,which occur to blue shift when the substituted is the electron receptor group.This result indicates that the different electronegativity substituents on 4'-phenyl influence the fluorescence properties of 4'-phenyl-2,2':6',2"-terpyridine compounds.2.In order to study the fluorescence properties of terpyridine metal complexs,a series of zinc,silver and cadmium metal complexes with substitueted 4-phenyl-2,2':6',2"-terpyridine ligands(L5,L9 and L11)were synthesized.The metal complexes were characterized by IR,NMR and X-ray diffraction.In the crystal structures,the results show that the hydrogen bond and ?-? stacking interaction act as the mainly forces to form the three-dimensional network system.Four main factors have been found to affect the fluorescence properties of terpyridine metal complexes,including substituents with the different electronegativity properties at the 4'-phenyl;the properties of anions;coordination model and the metal cations.At the same time,in order to study the effect of substituents on the fluorescence properties of terpyridine metal complexes,the fluorescence of eight zinc dibromide complexs with substitueted 4'-phenyl-2,2':6',2"-terpyridine were meansured.The results are indicative that there is only a single fluorescence emission peak,which is obviously different to the fluorescence emission peaks of ligands.The change of the maximum emission peak is similar to the fluorescence of ligands.These results indicate that the substituents of different electronegativity have the same effect on the fluorescence properties of substitueted 4'-phenyl-2,2':6',2"-terpyridine complex.3.The DFT quantum chemical calculations of three ligands and eight 4'-phenyl-terpyridine zinc dibromide complexes have been carried out on the gaussrian 09 software packages.In the geometry optimization calculation of ligands,Type A structure is closer to the real structure of three terpyridine ligands.In the calculation of the HOMO-LUMO orbit and the energy gap of the three ligands,it is found that the excitation process of the ligand is ILCT,and the fluorescence emission spectra of the ligands were also be simulated.The simulation results are well coincide with the experimental values.After the analysis of the charge transfer,a conclusion is obtained that the substituents have an effect on the charge transfer amount on the pyridine ring of the terpyridine.When the charge transfer amount on the pyridine ring increases,the conjugation effect strengthen and cause the intensity of fluorescence increasing with the red shift,otherwise,the blue shift is found and the intensity of fluorescence declines.After the same calculation of the complexs,a result is found that the excitation process belongs to MLCT,which is similar to the result of the ligand calculation.The calculation results of the fluorescence emission spectrum are also fit to the experimental results.At the same time,the electron receptor groups reduce the energy of the ground state of the terpyridine compounds,but the energy gap of HOMO-LUMO are also decrease,making the complexes easier to excite.It is also found that with the change of the properties of the substituent electrons,the charge transfer on the zinc dibromide also change).After the charge transfer from the zinc dibromide,it mainly distributes in the pyridine ring.When the charge transfer amount on the pyridine ring increases,the conjugation effect strengthens and the intensity of the fluorescence increases with the red shift,otherwise the fluorescence occurs to the blue shift and its intensity declines.The results show that the influence of substituents on the fluorescence properties of terpyridine series compounds is mainly related to the change of charge transfer on the pyridine ring.