Synthesis And Structural Characterization Of Iridium (â…¢) Complexes With 2 - Phenylpyridine And Its Derivatives As Ligand

Flat planer-display technique, a new generation of the most competitive preponderance, applied in OLED(Organic Light-Emitting Diode). Luminescent material is a core component of device,and heavy metal complexes with iridium core,of which heavy atom effect can generate the strong spin-orbit coupling as a result of reinforcing intersystem crossing from the singlet to triplet state and achieving strong phosphorescence emission so as to improve efficiency of the luminescence.The type of Ir(C∧N)3,three of the same ligand,have two isomers of facial and meridional type. The facial isomer with C3 axis of symmetry is the product of thermodynamics,and photophysical property is better than the meridional isomer.Thesis makes a research of the specific technology conditions, including reaction mechanism,the ratio of materials,feeding sequence and reaction conditions on the basis of the method of Iridium complexes preparation reported by related literature.Taking the iridium chloride hydrate as raw material,the chlorine bridge dimer as intermediate and selecting high temperature condition of 205℃for the synthesis of the iridium complexes of facial tris-(2-phenylpyridine)Iridium——Fac-Ir(ppy)3 and facial tris-[2-(p-tolyl)pyridine)]Iridium——Fac-Ir(tpy)3. In addition,taking the dimmer and auxiliary ligand Hacac for the synthesis of bis-[2-(p-tolyl)pyridine]Ir(acetylacetonate)——(tpy)2Ir(acac),which belongs to the type of Ir(C∧N)2(LX),and successfully obtain its crystal.For the purpose of it’s molecular structure,these complexes are characterized by the analysis methods of IR,MS,1H-NMR,13C-NMR and the crystal of(tpy)2Ir(acac)is characterized by XRD. The absorption and emission spectra of these complexes on optical properties are detected by means of UV-Vis and photoluminescence spectrum.The results show that the characteristic absorption bands at less than 300 nm are assigned to the spin-allowed( Ï€â†'Ï€*) transitions of the singlet state on ligand,and the two of weaker and broad absorption bands at 400 — 500 nm are assigned to the spin-allowed metal to ligand charge-transfer of the singlet state(1MLCT) and the spin-prohibited metal to ligand charge-transfer of the triplet state(3MLCT).Compared the absorption of S0â†'3MLCT with S0â†'1MLCT,these complexes manifest less red shift of different degrees respectively and similar absorption intensity,it is show the spin-prohibited 3MLCT is close to the spin-allowed 1MLCT due to the exist of Iridium.Moreover, they are measured and found stronger photoluminescence at 512,513,516 nm respectively,indicating that these complexes are green materials.