Study of the Synthesis of Oligo(phenylenevinylene)sand Their Photophysical and Optoelectronic Properties /Stereoselective Synthesis of (Z)-a-Phenoxymethy-lene-g-butyrolactone from 2-Propynyloxybenzene

• Main Authors: Sheng-Li Ko, 柯勝利
• Other Authors: none
• Format: Others
• Language: en_US
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/14727160220889249102

博士 === 國立中央大學 === 化學工程與材料工程研究所 === 91 === A series of distyrylbenzene (DSB) derivatives, as oligo(para-phenylene- vinylene) (OPV), were synthesized and assessed as the emitter in organic light emitting diode (OLED) fabrication. The presence of electron-withdrawing cyano group and electron-donating methoxy group at various positions in the molecule to evaluate their influence on the photophysical property and the electroluminescent behavior of these derivatives in OLED were studied. Bright blue emissions were achieved with these materials as a dopant. There were not much difference in the absorption and emission spectra of the compounds containing n-hexyloxy and 2-ethylhexyloxy groups. However, 2-ethylhexyloxy groups produce more saturated blue color in their EL. The compounds with higher fluorescent quantum yield did not result in higher EL quantum efficiency in this multiplayer OLED fabrication as that of compounds with lower fluorescent quantum yield. DSB derivatives with cyano and alkoxy groups grew epitaxially on the friction-transferred poly(tetrafluoroethylene) (PTFE) layer. DSBs/PTFE double layers indicated the remarkable anisotropic feature in absorption and emission properties. We concluded that trans,trans-1,4- di(2-ethyl-hexyloxy)-2,5-bis[2-(4-cyanophenyl)ethenyl]benzene molecules take two kinds of orientations on the PTFE layer in which the long axes of trans,trans-1,4-di(2-ethyl-hexyloxy)-2,5-bis[2-(4-cyanophenyl)ethenyl]benzene are parallel and normal to the substrate surface. On the other hand, the long axes of trans,trans-1,4-di(2-ethylhexyloxy)-2,5-bis[2-(2-cyanophenyl)ethenyl]- benzene and trans,trans-1,4-di(2-ethyl-hexyloxy)-2,5-bis[2-(3-cyanophenyl)-ethenyl]benzene ori- ent inclined and parallel to the substrate, respectively. Treatment of conjugated alkynone with NaI, TMSCl, and water in acetonitrile gave deconjugated (Z)-3-iodo-3-alken-1-one in good yield and with high stereoselectivity (≥95%). Mechanistic study showed that HI, generated from NaI, TMSCl and water, underwent regioselective addition to the conjugated ynone, e.g. 3-decyn-2-one, to form (E)-4-iodo-3-decen-2-one and (Z)-4-iodo-3-decen-2- one. Then, TMSCl catalyzed the deconjugation reaction to form deconjugated (Z)-4-iodo-4-decen-2-one. The application of the above deconjugation reaction was demonstrated by the stereoselective synthesis of (Z)-α-phenoxy-methylene- γ-butyrolactone and its hydrofuran analogues. DNA cleavage study also showed that γ-butyrolactone with (Z)-configuration at α-alkylidene gave better result than its analogue even at 10µM for only 10 min. The development of an efficient method for the preparation of (Z)-α-phenoxy-methylene-γ-butyrolactone and (Z)-α-phenylthiomethyl-γ-butyro- lactone derivatives from 2-propynyoxybenzene and 2-propynylthiobenzene were described.