title: Asymmetric multibranched conjugated molecules: synthesis, structure and photophysical properties.
abstract: The symmetric multibranched π-conjugated compounds with C3 or C6 configuration have been intensively studied. The reports on asymmetric multibranched compounds are very limited. In this work, we designed and synthesized two asymmetric multibranched π-conjugated molecules using truxene as the central core, diphenylamino and thiophenyl (or thiophenylethynyl) groups as the different branches respectively: 2,7-di(N,N-diphenylamino)-12-(2-thiophenyl)-5,5',10,10',15,15'-hexaethyltruxene and 2,7-di(N,N-diphenylamino)-12-(2-thiophenylethynyl)-5,5',10,10',15,15'-hexaethyltruxene. Their photophysical properties have been explored combining with their theoretical calculation and X-ray single-crystal structure of a key intermediate. Though their different π-conjugation length of branches, the two title compounds exhibit almost same absorption maxima. However, their emission peaks behave a gradual red-shift with the increase of the conjugation length. The theoretical calculation results indicate that the two asymmetric compounds behave a main transition from the HOMO-1 to the LUMO or from the HOMO to the LUMO+1 upon excited.
authors: College of Science, Northwest A&F University, Yangling 712100, PR China; Hospital, Northwest A&F University, Yangling 712100, PR China.
authors: Li
authors: L
authors: Zhao
authors: College of Science, Northwest A&F University, Yangling 712100, PR China.
authors: Wenji
authors: W
authors: Wang
authors: College of Science, Northwest A&F University, Yangling 712100, PR China; State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, PR China. Electronic address: yuanms@nwsuaf.edu.cn.
authors: Mao-Sen
authors: MS
authors: Yuan
mesh_terms: D018360:Crystallography, X-Ray; D005449:Fluorenes / Q000138:chemical synthesis* / Q000737:chemistry*; D005663:Furans / Q000737:chemistry; D049449:Luminescence; D008968:Molecular Conformation; D055585:Physical Phenomena; D012997:Solvents; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet
chemical_list: D005449:Fluorenes; D005663:Furans; D012997:Solvents; C018674:tetrahydrofuran
keywords: Charge transfer; Crystal structure; Photophysical properties; Thiophene; Truxene