DNA碱基激光光解的新颖瞬态产物

本文报道了利用纳秒级激光光解瞬态吸收光谱技术研究DNA碱基光解和光敏作用的结果:发现了胸腺嘧啶的一个新激发三重态和胸腺嘧啶羟基加合物自由基的生成;首次观察到胞嘧啶及其衍生物胞嘧啶核苷、脱氧胞嘧啶核苷酸的激发三重态光吸收谱;确证了鸟嘌呤核苷的激发三重态,其pK_a值为8.7;并研究了上述瞬态产物的动态演变过程,总结了其反应机理。     

Novel Transient Species of DNA Bases From Laser Photolysis

The laser photochemistry and photosensitization of DNA bases were carried out by using a nanosecond kinetic spectroscopy. A novel triplet state of thymine and its OH adduct were observed in N_2 and N_2O saturated aqueous solution respectively. The transient absorption spectra of triplet cytosine, cytidine and deoxycytidine monophosphoric acid were observed for the first time. Triplet guanosine was confirmed and its pK, value, 8.7, was obtained. Kinetic studies of the growth-decay of the above transient species were performed and their reaction mechanisms were elucidated in detail.     

抗氧化剂防止品红甲亚胺染料光褪色的作用机制

本文利用激光光解动态吸收光谱研究了氧与品红甲亚胺染料间的作用,发现染料的光褪色不仅与单重态氧有关,氧的自由基负离子也可能是引起褪色的一个重要因素.还研究了抗氧化剂对品红甲亚胺染料激发态的影响,证实前者对染料激发态有猝灭作用,据此对抗氧化剂防止品红甲亚胺染料光褪色机理作了进一步探讨.