[The Design, Synthesis, Characteristics and Photoelectric Properties Research of A Bulky Steric Hindrance 9-Phenyl-Fluorene Functionalized Aniline Intermediate].

ABSTRACT

In this paper, with sulfuric acid as a catalyst and acetic acid as solution at the temperature of 120 ℃ and refluxing period for 24 hours, a sterically hindered bulky 9,9-diarylfluorene intermediate of [9-(4-anilino)-9-phenyl-fluorene] had been successfully designed and synthesized with Friedel-Crafts reaction. The molecular structure of this compound was characterized in detail with nuclear magnetic resonance hydrogen spectrum, mass spectrometry, infrared ray, and so on. Nuclear magnetic resonance hydrogen spectrum and infrared ray spectrum of the compound indicated that the characteristic functional group amino of the compound at 6.55 ppm, 3 481 and 3 385 cm-1, respectively. UV-visible and fluorescence spectra properties of 9-(4-anilino)-9-phenyl-fluorene were characterized and discussed preliminarily, respectively. The research results show that the 9-(4-anilino)-9-phenyl-fluorene with bulky steric hindrance effects has four main absorption peaks with wavelength of 243, 257, 298 and 311 nm in dichloromethane solution, respectively. Moreover, with the excitation wavelength of 308 nm, an emission spectrum curve was obtained with wavelength of 300～500 nm, which has the maximum emission peak of 328 nm with a slim peak at about 405 nm and a long tail to 500 nm. The long tail was probably attributed to the interaction of intermolecular hydrogen bonding from aniline. The appropriate scope of fluorescence emission (300~500 nm) make the compound overlap with the absorption spectra of the classic blue material Bis(3,5-difluoro-2-(2-pyridyl)phenyl-(2-carboxypyridyl)iridium (Ⅲ) (FIrpic) (300~500 nm). It is possible to obtain excellent host materials through proper molecular tailoring and prepare well for high performance light-emitting device. In order to further understand the photoelectric properties of the compound, we used acetonitrile as solvent and tetrabutylammonium hexafluorophosphate as electrolyte, and the electrochemical properties of the compound was characterized with cyclic voltammetry measurements.The onset of the reduction and oxidation potential of the compound are -0.759 and 0.898 V, and the corresponding HOMO and LUMO energy levels are -5.38 and -3.72 eV, which wolud be beneficial to holes and electrons injection/transportation and further modified to be excellent host materials. All of these data would provide a useful reference for further fabrication of organic semiconductor luminescent device with high performance.