[4 + 2] Cycloaddition Reaction To Approach Diazatwistpentacenes: Synthesis, Structures, Physical Properties, and Self-assembly

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• 作者：Junbo Li ; Peizhou Li ; Jiansheng Wu ; Junkuo Gao ; Wei-Wei Xiong ; Guodong Zhang ; Yanli Zhao ; Qichun Zhang
• 刊名：Journal of Organic Chemistry
• 出版年：2014
• 出版时间：May 16, 2014
• 年：2014
• 卷：79
• 期：10
• 页码：4438-4445
• 全文大小：484K
• 年卷期：v.79,no.10(May 16, 2014)
• ISSN：1520-6904

文摘

Three novel diazatwistpentacenes (1,4,6,13-tetraphenyl-7:8,11:12-bisbenzo-2,3-diazatwistpentacene (1, IUPAC name: 9,11,14,16-tetraphenyl-1,6-dihydrobenzo[8,9]triphenyleno[2,3-g]phthalazine); 1,4-di(pyridin-2-yl)-6,13-diphenyl-7:8,11:12-bisbenzo-2,3-diazatwistpentacene (2, IUPAC name: 9,16-diphenyl-11,14-di(pyridin-2-yl)-1,6-dihydrobenzo[8,9]triphenyleno[2,3-g]phthalazine); and 1,4-di(thien-2-yl)-6,13-diphenyl-7:8,11:12-bisbenzo-2,3-diazatwistpentacene (3, IUPAC name: 9,16-diphenyl-11,14-di(thien-2-yl)-1,6-dihydrobenzo[8,9]triphenyleno[2,3-g]phthalazine)) have been successfully synthesized through [4 + 2] cycloaddition reaction involving in situ arynes as dienophiles and substituted 1,2,4,5-tetrazines as dienes. Their structures have been determined by single-crystal X-ray diffraction, confirming that all compounds have twisted configurations with torsion angles between the pyrene unit and the 2,3-diazaanthrance part as high as 21.52掳 (for 1), 24.74掳 (for 2), and 21.14掳 (for 3). The optical bandgaps for all compounds corroborate the values derived from CV. The calculation done by DFT shows that the HOMO鈥揕UMO bandgaps are in good agreement with experimental data. Interestingly, the substituted groups (phenyl, pyridyl, thienyl) in the 1,4-positions did affect their self-assembly and the optical properties of as-resulted nanostructures. Under the same conditions, compounds 1鈥?b>3 could self-assemble into different morphologies such as microrods (for 1), nanoprisms (for 2), and nanobelts (for 3). Moreover, the UV鈥搗is absorption and emission spectra of as-prepared nanostructures were largely red-shifted, indicating J-type aggregation for all materials. Surprisingly, both 1 and 2 showed aggregation-induced emission (AIE) effect, while compound 3 showed aggregation-caused quenching (ACQ) effect. Our method to approach novel twisted azaacenes through [4 + 2] reaction could offer a new tool to develop unusual twisted conjugated materials for future optoelectronic applications.