羧脒盐桥介导的单重态能量传递直接观察

Direct Observation of Singlet-Singlet Energy Transfer Mediated by an Amidinium Carboxylate Salt Bridge

设计构建了以羧脒盐桥联接的萘和蒽超分子组装体系,NA-(脒基-羧基)-An以及相应的模型体系.稳态和时间分辨荧光光谱研究表明,置于羧脒盐桥两端的萘和蒽基团之间发生了从萘到蒽的单重态能量传递,NA-(脒-羧)-An超分子体系中单重态能量传递效率和速率常数分别大于0.99和9.9×109s-1.推测羧脒盐桥介导了体系中的单重态能量传递过程,单重态能量传递‘通过键’以电子交换机制进行.

The Amidinium-Carboxylate salt bridge system bearing a pair of singlet energy transfer donor （naphthalene,NA） and acceptor （anthracene,An）,NA-（amidinium-carboxylate）-An was designed and assembled. Steady-state and time-resolved fluorescence studies demonstrate that the singlet-singlet energy transfer from NA to An can occur efficiently within the supramolecular system NA-（amidinium-carboxylate）-An. The efficiency and rate constant are estimated to be larger than 0.99 and 9.9×109 s-1. We infer that the singlet-single energy transfer proceeds via a ‘through-bond’ electron exchange mechanism,and mediated by the amidinium-carboxylate salt bridge.