Through palladium-catalyzed Heck reaction, a novel fluorescent dentrimer 1,2,4,5-tetra{4-{N, N-di{4-[4-(N, N- diphenylamino)styryl]phenyl}amino}styryl}benzene (TPAB-TPA) was synthesized by aromatic octoiodine-substituted 1,2,4,5-tetra{4-[N, N-bis(4-iodophenyl)amino]styryl}benzene (TPAB-I) and N, N-diphenyl-4-vinylaniline. Its structure was characterized through IR, ¹H NMR, HRMS. A detailed spectroscopic study of the dendrimer TPAB-TPA, including absorption, fluorescence emission, fluorescence lifetime and fluorescence quantum yield, was conducted. The maxima emission wavelengths of TPBA-TPA in toluene, ethyl acetate, THF, dichloromethane and DMF were at 483, 457, 497, 531 and 505 nm, respectively. The absorption peaks of the dendrimer were at 400 nm in dichloromethane solution and at 405 nm in DMF solution. The quantum yield was 0.48 (in toluene), 0.28 (in ethyl acetate) and 0.49 (in dichloromethane). The dendrimer possess high solubility in organic solvents and large Stoke’s shift (3434～6168). The fluorescence lifetime was 1.53 ns in THF and 1.48 ns in dichloromethane. The electrochemical properties of the dendrimer TPAB-TPA were explored by cyclic voltammetry. Its HOMO energy level was -5.16 eV and LUMO energy level was -2.64 eV. An organic electrical memory device with the sandwich structure of indium-tin oxide (ITO)/TPAB-TPA/Al was fabricated. The device exhibits a flash memory effect with a high ON/OFF current ratio nearly 10⁴ and a long retention time above 10³ s with a read voltage 1.0 V.

Key words: dentrimer, Heck reaction, electrical storage, fluorescent properties, electrical bistability