Synthesis of Two-Photon Absorbing Unsymmetrical Branched Chromophores through Direct Tris(bromomethylation) of Fluorene
摘要:
Branched fluorene-based chromophores bearing electron-donating diphenylamino or electron-withdrawing nitro groups were synthesized as well as their linear analogues. An efficient synthetic method was developed via a novel 2,4,7-tris(bromomethyl)-9,9-diethylfluorene intermediate. The bromomethyl groups in this key intermediate were converted to either phosphonate or carboxaldehyde moieties, facilitating preparation of a high functionality branched structure. It was found that the reactivity at position 4 is attenuated in the bromomethyl and phosphorylated derivates, facilitating the selective and systematic functionalization of the fluorenyl system. All compounds were stable up to ca. 350 degrees C, except for a sterically crowded branched derivative. The linear optical properties of the compounds were investigated by UV-visible, steady-state fluorescence, and excitation anisotropy spectroscopic measurements. Fluorescence quantum yields were greater than or equal to 0.84 for symmetric linear and unsymmetric branched derivatives. Very high two-photon absorption (2PA) cross-sections were achieved (5765 GM at 520 nm and 4194 GM at 570 nm), as determined with use of picosecond and femtosecond laser excitation sources, respectively.
Electroluminescent Properties of Novel Fluorene Derivatives with Aromatic Amine Moieties
摘要:
2,7-Bis[(4-diphenylamino)phenylvinylene]-9,9-diethylfluorene(BDPDF, 1) and 2,7-bis[(9-ethyl-3-carbazolylvinylene)-9,9-diethylfluorene(BECDF, 2) have been synthesized and characterized. To evaluate electroluminescent performance, compound 1 and 2 were used as emitting materials and dopant materials, respectively and the basic device structure was ITO/m-MTDATA/a-NPD/1 or 2 or doped DPVBi with 1 or 2/Alq 3 /LiF/Al.The devices using BDPDF(1) and BECDF(2) show EL peak at 470 nm and 486 nm. The device showed a blue light-emission with the CIE chromaticity coordinates of (0.177, 0.268).
In this paper, we reported the synthesis and electroluminescentproperties of blue fluorescent styrylamine derivatives end-capped with a diphenylvinyl group. A new series of styrylamine derivatives have been synthesized via the HornerWadsworth-Emmons reaction. To explore electroluminescentproperties of these molecules, multilayer organic lightemitting devices with the configuration of ITO/NPB/1-5
A series of new N-arylpyrrole-based chromophores with the donor-pi-donor structure have been designed and synthesized via Wittig-Homer-Emmons olefination and Suzuki coupling reactions. The electronic and optical properties of the designed chromophores could be well tuned by modifying the conjugation bridges and changing the groups linked to the pyrrole moieties through the C-N single bond. All the chromophores exhibited two-photon absorption activity in the range of 730-900 nm with a large two-photon absorption cross section (similar to 1000-1700 GM).