Synthesis And Property Of Zinc Complex 8-hydroxyquinoline

Organic ligand metal complexes with 8-hydroxyquinoline has been extensively appliedto the OLED. Due to the complexes have low consumption, high brightness, good filmformation and thermal stability, so these complexes has become the ideal organiclight-emitting materials. But the emission of these complexes is yellow-green, and can’t meetthe demand of full color. The emission spectrum of metal complexes 8-hydroxyquinolinewere mediated by chemical modification. This approach has made important application valueto enich the application range of the eletroluminescene materials and optimize theeletroluminescene equipments.In this study, four kinds of 8-hydroxyquinoline conjugate bonded derivatives and theirZn complexes were designed and synthesised. The preparation departs from2-methyl-8-quinolinol, which reacts to the 4-methoxy-benzaldehyde, 4-dimethy-laminobenzaldehyde, 2-(4-imidazolylstyryl)-8-quinolinol, N-ethyl-3-formylcarbazole bycondensation reaction with acetic anhydride as solvent yield acetyl 8-hydroxyquinolinederivatives. Their dehydrated derivatives yield after hydrolysis and neutralization. Their Zncomplexes yield by ligands reacted with acetic zinc. These novel compounds werecharacterized by IR,1H NMR and elemental analysis. And the melting point of these novelcompounds were measured by melting point apparatus.The experiment proves that the influence factors of condensation reaction were discussedin this paper. The results showed that preparation of four kinds of 8-hydroxyquinoline ligandshad the same optimum reaction conditions, that the optimum mole ratio of aldehydes to2-methyl-quinolin-8-ol is 1.1:1, the reaction time is 40 h, the suitable temperature is 130℃.The optical characterization of these new substituted 8-hydroxyquinolines are beingdiscussed. The photoluminescence spectra show that emission peaks of complexes 1, 2, 3 and4 are at 593 nm, 601 nm, 628 nm and 586 nm, with yellow, orange red, red and orange yellow light emitted, respectively. After analysised the emission spectrum of the compounds, all themax luminescent wavelengths are red shifted 100 nm compared with2-methyl-8-hydroxyquinoline zinc. It is possibly suggested that the different fluorescencespecteum is ascribed to the formation of the new transition energy level caused by thesubstitution of conjugated systems, which leads to the change of the energy gap betweenHOMO and LUMO, these complexes were synthesized successfully which can control theemission spectrum range. The thermo-gravimetric measurement was measureed on these2-substituted-8-hydroxyquinoline Zn complexes from 20 to 700℃. The results showed thatthey had good thermal stability. Complex 3 had favorable performance in fluorescence, Weprepare organic electroluminescent device and the properties of device were tested.