超分子屏蔽效应对富勒烯自由基C_(59)N·稳定性的影响及其诱导的(C_(59)N)_(2)中键接碳笼C-C键的转移重构

Effect of supramolecular shielding on the stability of fullerene radical C_(59)N·and its induced reconstruction of C-C bond in(C_(59)N)_(2)

富勒烯自由基通常是在空气中短暂存在或不稳定的短寿命物种,超分子屏蔽是近年来被发展用于稳定富勒烯自由基稳定的一种有效策略.本文将共价桥联碳质π电子共轭双嵌N分子碗作为客体C_(59)N·富勒烯自由基的理想宿主体,通过密度泛函理论计算研究了二者之间的主客体相互作用、热力学、自旋电子密度等性质.结果发现C_(59)N·富勒烯自由基嵌螯在该钳形双分子碗的凹穴内而被屏蔽,从而有效避免单电子结构的暴露和C_(59)N·自由基之间的化学二聚,即显著增强其动力学稳定性和寿命,这种策略对富勒烯自由基在自旋电子学、超分子电子器件或光电转换器件等领域的应用具有潜在指导价值.此外,本研究还发现通过超分子屏蔽策略,理论上可以实现对(C_(59)N)_(2)二聚体分子中键连两个碳笼的C-C进行重构,这也为富勒烯相关体系中C-C键构建的提供了一种新的思路与途径.

Fullerene radicals are usually short-lived or unstable species in the air.Supramolecular shielding is an effective strategy developed to stabilize fullerene radicals in recent years.In this paper,covalently bridged carbonaceousπelectron conjugated double embedded N atom bimolecular-bowl is used as the ideal host of guest C_(59)N·fullerene radical.The host-guest interaction,thermodynamics and spin electron density are studied by density functional theory.The results show that the C_(59)N·fullerene free radical is blocked in the recess of the pincer bimolecular-bowl,so as to effectively avoid the exposure of single electron and the chemical dimerization between C_(59)N·free radicals,that is,significantly enhance its dynamic stability and lifetime.This strategy has potential guiding value for the application of fullerene radicals in spintronics,supramolecular electronic devices and photoelectric converters.In addition,it is also found that through the supramolecular shielding strategy,we can theoretically reconstruct the C-C bonded to two carbon cages in(C_(59)N)_(2) dimer molecules,which provides a new way for the construction of C-C bond in fullerene related systems.