扩环荧光碱基类似物x-腺嘌呤分子基态和激发态性质的理论研究

近年来, 设计合成荧光碱基类似物成为科学家研究的一个热点. 利用含时密度泛函理论考察了腺嘌呤类似物x-腺嘌呤的电子激发态性质, 计算了其电子吸收光谱和荧光光谱, 并对其若干低能电子激发态进行了详细解析归属. 同时考察了甲醇溶剂、糖环和与胸腺嘧啶配对对其光谱性质的影响. 研究表明, 在低能区域, x-腺嘌呤的吸收光谱与天然腺嘌呤相比发生了很大红移, 使其可以被选择性地激发. 计算得到的吸收光谱和荧光光谱与实验值符合很好. 溶剂化和糖环对x-腺嘌呤的电子吸收光谱具有增色效应, 同时发现溶剂化和糖环均使其荧光发生红移, 而碱基配对对其最低激发态ππ^* 和荧光发射无显著影响, 但使其最低nπ^* 态发生显著蓝移. 关键词： x-腺嘌呤')" href="#">x-腺嘌呤 电子吸收光谱 荧光光谱 含时密度泛函

Theoretical study of the ground and excited state properties of newly designed size-expanded adenine analogue x-adenine

Recently, creating unnatural fluorescent nucleobase analogues has gained increasing attention. In this work, a detailed computational investigation on the photophysical properties of the fluorescent adenine analogue x-adenine (xA) is carried out. The ten lowest low-lying exited states are analyzed and assigned. The effects of methanol solution, linking to deoxyribose, and base pairing on its absorption and emission processes are considered. The calculated excitation and emission energies are in good agreement with the measured data available. It is found that linking to deoxyribose and methanol solution have a hyperchromic effect on xA. Also it is found that methanol solution and linking to deoxyribose will lead to the red shift of fluorescence, while base pairing does not have obvious effects on the lowest ππ^* state and fluorescence emission but produces the blue shift of lowest nπ^* to some extent.
Keywords： x-adenine')" href="#">x-adenine electronic spectra fluorescence spectra time-dependent density functional theory