Studies On The Synthesis And Properties Of Aromatic Heterocyclic Small Molecular Photoelectric Functional Materials

The design, synthesis, characterization and application of organic molecules aselectro-optical materials have become an active and interesting subject due to theirextensive application in many fields. In this thesis, thirteen kinds of aromatic heterocycliccompounds including carbazole heterocyclic schiff bases, ethylene type bis-benzimidazolederivatives and acetylacetone shrink2-aminobenzimidazole schiff base complexes of rareearth metals were designed and synthesized. The above compounds were characterized byelemental analysis, IR,1HNMR and Using UV-Vis, fluorescence, cyclic voltammetry,and thermal analysis to show their performance. The details were as follows:(1) Intermediate N-ethyl-3,6-diamino-carbazole and quinoxalin-2-carbaldehyde weresynthesized by carbazole, o-phenylenediamine and fructose which were choosed as rawmaterials. Then four kinds of unreported double schiff bases including quinoxaline-2-formaldehyde shrink N-ethyl-3,6-diaminocarbazole(S1), salicylaldehyde shrink N-ethyl-3,6-diaminocarbazole(S2), cinnamic aldehyde shrink N-ethyl-3,6-diaminocarbazole (S3),furfurylidene shrink N-ethyl-3,6-diaminocarbazole (S4) were synthesized by dehydrationcondensation which using salicyl aldehyde, cinnamic aldehyde, furfural,quinoxaline-2-formaldehyde and N-ethyl-3,6-diaminocarbazole as reactant. The results offluorescence test showed that their solution fluorescence emission peaks were at410,430nm(violet fluorescence),532nm (green fluorescence),442nm(blue-violet fluorescence),446nm (blue-violet fluorescence) respectively. Solid fluorescence spectroscopy showedthat S1, S2had emission peaks at572nm (yellow fluorescence) and548nm (greenfluorescence). Comparing to the solution, the peaks occurred red shift. S2had a significantAIE performance. Cyclic voltammetry (CV) test results showed that ionization potential ofS1-S4=4.99-6.17eV which match with an ionization potential of the positive electrodeITO (4.8eV), showing that S1-S4had good hole transporting ability. TG/DTA analysisshowed that the thermal decomposition temperature of S1-S4=319-363℃, showing thatS1-S4had good thermal stability.(2) Intermediates bibenzimidazole methane and N-ethyl-carbazole-3-carbaldehydewere synthesized using carbazole, o-phenylenediamine and malonate as main rawmaterials. Then three kinds of bis-benzimidazole derivatives including1,1-bis (benzoimidazol-3-yl)-2-(N-ethyl-carbazol-3-yl) ethylene (Y1),1,1-bis (benzoimidazol-3-yl)-2-(quinoxalin-2-yl) ethylene (Y2) and1,1,1，,1，-tetrakis (benzoimidazol-3-yl)-1,4-divinylbenzene (Y3) were synthesized by dehydration condensation which using N-ethyl- carbazole-3-carbaldehyde, quinoxaline-2-formaldehyde and terephthaldehyde as reactant.The results of fluorescence test showed that their solution fluorescence emission peakswere at470nm,491nm,503nm respectively, which showing that Y1and Y2wereblue-green fluorescence, and Y3was green fluorescence. Solid fluorescence spectroscopyshowed that Y1-Y3had strong solid fluorescence peak at484nm(blue-greenfluorescence),610nm(yellow fluorescence),551nm (green fluorescence). Comparing tothe solution, the peaks occurred red shift. Y1, Y3had significant AIE performance. Cyclicvoltammetry (CV) test results showed that ionization potential of S1-S4=5.43-5.67eV,matched with an ionization potential of the positive electrode ITO (4.8eV), showing thatY1-Y3had good hole transporting ability, but the electron affinity of Y1is2.85eV,matched with PBD, showing that Y1aslo had good electron transporting ability. TG/DTAanalysis showed that the thermal decomposition temperature of Y1-Y3=421-500℃,showing that Y1-Y3had good thermal stability.(3) Using acetyl acetone (Acca) and2-amino-benzimidazole (Abm) and rare earthmetals of nitrate as raw materials, with the mole ratio Acca: Abm: RE (NO3)3=2:2:1, sixnew schiff base complexes C1-C6were synthesized by“one-pot”. The structure of targetcompounds were characterized by Elemental Analysis, IR,1H NMR and TG-DTA tests.Their formula were Re (L)2(NO3)3(Re=Nd (Ⅲ), Tb (Ⅲ), L=C12H13N3O) and ReL0(NO3)3(Re=Eu (Ⅲ), Ce (Ⅲ), Dy (Ⅲ) Sm,(Ⅲ), L0=C19H18N6). Their conductivity was105-120μS/cm, greater than the conductivity of the DI water (90μS/cm) in the sameconditions which descriped that C1-C6are ionic complexes. The results of fluorescencetest showed that their solution fluorescence emission peaks all at477nm, which wasblue-green fluorescence. Solid fluorescence spectroscopy showed that they had strong solidfluorescence peak at454-500nm, which was blue-green fluorescence. Comparing to thesolution, the peaks occurred red shift. Cyclic voltammetry (CV) test results showed thationization potential of C1-C6=5.03-5.47eV, matched with an ionization potential of thepositive electrode ITO (4.8eV), showing that C1-C6had good hole transporting ability.TG/DTA analysis showed that the thermal decomposition temperature of Y1-Y3=223-262℃.In conclusion, eleven heterocyclic compounds with strong solid fluorescenceincluding S1, S2, Y1-Y3, C1-C6(ionic complexes) and Three heterocyclic compounds withAIE performance including S2, Y1, Y3were obtained from the three series products. Threeseries can be used as a hole transport material, thereinto Y1was a bipolar material whichhad light-emitting properties and carriers (holes and electrons) transmission performance.