Synthesis And Characterization Of 1,4-Distyrylbenzene Derivatives

In this dissertation, seven 1,4-distyrylbenzene derivates with different substituent groups have been synthesized by Wittig-Horner reaction. The structures of these compounds were chracterized by methods such as: the melting point testing, FT-IR, 1H-NMR and MS spectra. These compounds have good solubility in organic solvents with strong polarity such as N,N-dimethylformamide, but have different solubility in general solvents. Among the nine compounds, N,N'-(4,4'-(1E,1'E)-2,2'-(1,4-phenylene)bis(ethene-2,1-diyl)bis(4,1-phenylene))bis(4-methyl-N-p-tolylbenzenamine) (4c) and 1,4-bis((E)-2-(9-hexyl-9H-carbazol-3-yl)vinyl)benzene (4f) can also dissolve in chloroform, tetrahydrofuran, dichloromethane, and so on.The effects of the substituent groups introduced to the two sides of 1,4-distyrylbenze and the physical properties of the solvent have been studied by UV-Vis and Fluorescent spectra. The results have showed that the maximum absorption wavelengthsλmax, abs of the compounds in solvents mainly distribute in 350nm~420nm, while the emission wavelengthsλmax, em 430~490nm, emitting blue light, except for 4a, which emitting yellow light (540nm). Substituent groups cause bathochromic shift of both the absorption spectra and fluorescence spectra. With rigid triphenyl amino group and carbazole group, respectively, 4c and 4f both have bathochromic shifts over 40nm compared with non-substituent 1,4-distyrylbenzene. There is no obvious linear correlation between characterization of the absorption spectra (the maximum absorption wavelengthλmax, abs and molar absorption coefficientεmax) and the parameters of the solvents (refractive index n and permittivityε). In a whole,λmax, abs of the compounds increase along with the increase refractive index of the solvent, whileεmax decrease. In addition,λmax, em of the compounds increase along with the increase of permittivity of the solvent. Comparing the differences between the wave numbers ofλmax, abs andλmax, em of 4c and 4f with the function of polarizability in Lippert equation, it have been found good linear correlation between them.The energy levels of the compounds have been calculated from the absorption spectra and cyclic voltammetry. The optical band gaps were calculated by the onset absorption wavelength. The HOMO energy levels of 4c and 4f calculated from cyclic voltammetry were -5.38 and -5.35eV, respectively, which were similar to hole transporting material TPD. Both 4c and 4f are potential blue light emitting hole transporting materials.