基于萘二酰亚胺衍生物的给受体共晶的分子自组装和荧光变化

Molecular self-assembly and fluorescence change of donor-acceptor cocrystal based on naphthalimide derivatives

由两种或两种以上不同组分通过π-π相互作用、电荷转移和氢/卤键等非共价相互作用形成的有机共晶体,因其在有机光电子领域中的应用而受到广泛关注.本文通过溶液共结晶的方法制备了三种电荷转移共晶体,以晕苯和芘作为给体,萘二酰亚胺衍生物N,N′-二甲基-1,4,5,8-萘四甲酸二酰亚胺(N,N′-dimethyl-1,4,5,8-naphthalenetetracarboxylic diimide,NDI-1)和N,N′-双(乙基)-1,4,5,8-萘四甲酸二酰亚胺(N,N′-bis(ethyl)-1,4,5,8-naphthalenetetracarboxylic diimide,NDI-2)作为受体.详细的结构表征阐明了三种电荷转移共晶体中的混合堆积模式,堆积柱间的π-π相互作用、相邻分子柱间的C–H···O氢键形成的扩展网络支撑了整个晶体构型.有趣的是,与给体化合物相比,三种共晶体显示出不同的荧光发射现象,这与给受体之间形成受激电荷转移态相关.这种共结晶方法为新型有机发光双组分电荷转移复合物的设计提供了新的机遇.

Organic cocrystals formed by two or more components through π-π interactions, charge transfer, and hydrogen/halogen bondings have attracted extensive attention because of their applications in the field of organic optoelectronics. Here, we prepared three charge-transfer cocrystals by solution-process self-assembly method which used Coronene and pyrene as donors, N,N′-dimethyl-1,4,5,8-naphthalenetetracarboxylic diimide(NDI-1) and N,N′-bis(ethyl)-1,4,5,8-naphthalenetetracarboxylic diimide(NDI-2) as acceptors. Detailed structural characterizations clarified the mixed stacking mode in the charge-transfer cocrystals, and the supramolecular network was stabilized by C–H···O hydrogen bonds and π-π interactions. Interestingly, compared with the original donors, three cocrystals show different fluorescence emissions, which is related to the formation of charge-transfer states between donors and acceptors. This cocrystal strategy provides a new opportunity for the design of new organic light-emitting chargetransfer complexes.