分子内弱相互作用对共轭性的影响  

Influences of Intramolecular Weak Interactions on Conjugation

作　　者：张融 周颖 晏琦帆 ZHANG Rong;ZHOU Ying;YAN Qifan(Key Laboratory for Advanced Materials,Ministry of Education,School of Chemistry and Molecular Engineering,East China University of Science and Technology,Shanghai 200237,China)

机构地区：[1]华东理工大学化学与分子工程学院结构可控先进功能材料及其制备教育部重点实验室

出　　处：《华东理工大学学报（自然科学版）》2019年第6期899-909,共11页Journal of East China University of Science and Technology

基　　金：国家自然科学基金（J100-4-1615）

摘　　要：以[2,2]对环蕃、三蝶烯、9,9’-螺二芴为连接单元,通过Buchwald-Hartwig/Suzuki偶联反应,连接富电子二苯氨基/缺电子萘酰亚胺片段,合成了化合物1~6和化合物7~12。在化合物1~6和7~12中,两个富电子中心或两个缺电子中心通过本共轭、交叉共轭、π-π堆积以及直接π-共轭方式连接。光物理和电化学测试表明,中性状态下基态共轭性以直接π-共轭最好,本共轭、交叉共轭次之,π-π堆积最差;在正离子自由基状态下共轭性以直接π-共轭最好,本共轭、交叉共轭次之且相近;负离子状态下共轭性则由于缺电子中心和连接单元之间的π-共轭作用被π-平面之间的扭转角削弱,化合物7~12中的连接方式都未能体现出差异。Organic π-conjugated compounds have received great research attention due to their wide optoelectronic applications. Previous studies on tuning single molecular photoelectric properties of organic π-conjugated compounds focused on developing new π-skeletons and introducing electron-donating and withdrawing substituents. However, the influences of intramolecular weak interaction on the optoelectrical properties of organic π-conjugated compounds are lacking of study. Herein, we designed and synthesized compounds 1~ 6 and 7~ 12 via Buchwald-Hartwig/Suzuki coupling reactions, with [2,2]paracyclophane(cyclophane), triptycene, and 9,9 ’-spirobifluorene(spirofluorene) as the linking units, two electron-rich diphenylamino or electron-deficient naphthalimide as the substituents. In compounds 1~6 and 7~12, the two electron-rich or electron-deficient centers interact with each other via homo-conjugation, cross-conjugation, π-π stacking, and π-direct conjugation. Photophysical and electrochemical measurements revealed that at neutral state, interactions(conjugation-effect) created by homoconjugation in spirofluorene were lower than those created by direct π-conjugation, but were stronger than those created by cross-conjugation in spirofluorene, homo-conjugation in triptycene, and π-π stacking in cyclophane. When electronrich compounds 1~6 lost one electron, converting into a monocation, conjugation effect decreases in the following order: Direct π-conjugation, homo-conjugation in spirofluorene, homo-conjugation in triptycene, cross-conjugation in spirofluorene. All these results demonstrated that optoelectronic properties of π-conjugated organic molecules could be tuned by the intramolecular weak interactions.

关 键 词：分子内弱相互作用 共轭作用 [2 2]对环蕃 三蝶烯 9 9’-螺二芴 

分 类 号：O69[理学—化学]