Synthesis And Photoelectric Properties Of Pyrene-based Sulfides

Recently, organic photoconductive materials develop rapidly because of its potential application in the field of organic semiconductor. Pyrene as a typical condensed aromatic enriched in coal tar has aroused great attentions for its strong π electron resonance energy, easy modifiability and unique fluorescence properties. Therefore, pyene-based compounds are promising organic photoconductive materials. In this paper, pyrene was choosen as a precursor, and a series of pyrenyl sulfides have been designed and synthesized. Besides, their photoelectric properties and the relationship between photoelectric properties with molecular structure have been investigated. The concrete contains as follows:1. Based on 1-, 2- and 4-bromopyrenes, eight mono-substituted pyrene-based sulfides were synthesized. 1-position and 4-position benzene-containing pyrene-based sulfides behave weak luminescence in the dilute solution, but strong in the solid state with distinct red shift in emission wavelength, show aggregation-enhanced excimer emission(AEEE) property. Through the single crystal structure analysis, their moleculars were found having a twisted configation, and there exist different slip amount π-π and C-H···π interactions between the moleculars.While, 1-position and 4-position merhylthio-substituted pyrene-based sulfides give strong luminescence emission in the dilute solution and solid state. Studies on crystal structure have shown that their molecular configation are planar structure, there exist weak π-π interactions between the moleculars. 2-position substituted pyrene-based sulfides show similar spectroscopic properties with pyrene. Moreover, the emitting color of 1-position substituted pyrene-based sulfides changes obviously along with the molecular configation and packing state.2. Based on 1,6- and 1,8-dibromopyrenes, four disubstituted pyrene-based sulfides were synthesized. Since the conjugation system enlarged, absorption and emission wavelength of the four compounds shows a certain red shift compared to mono-substituted pyrene-based sulfides. Disubstituted benzene-containing pyrene-based sulfides behave slightly weaker luminescence than pyrene in the dilute solution, but stronger in the solid state. Through the single crystal structure analysis, their moleculars were found having a twisted configation, and there exist π-π and C-H···π interactions. Merhylthio-bisubstituted pyrene-based sulfides emit strong luminescence in the dilute solution, but weaker in solid state. Studies on crystal structure have shown that their molecular configations are planar structures, and there exist strong π-π interactions.3. Based on 7-tert-butyl-1-bromopyrene and 7-tert-butyl-1,3-dibromopyrene, four Y-shaped pyrene-based sulfides were synthesized. Y-shaped benzene-containing pyrene-based sulfides behave weak luminescence in the dilute solution, but strong in the solid state with distinct red shift in emission wavelength, show AEEE property. The single crystal structure analysis found that their molecular configations are also twisted, and there exist π-π and C-H···π interactions. Merhylthio-disubstituted Y-shaped pyrene-based sulfides emit strong luminescence in the dilute solution, but weaker in solid state. Studies on crystal structure have shown that its molecular configation is a planar structure, but the pyrene planar is somewhat bent due to the steric hindrance of tert-butyl. Besides, the distances between dimers become larger. To a certain extent, that could decrease the formation of π-π packing.