溶液酸碱性对腺嘌呤分子吸附构型影响的SERS光谱研究

核酸碱基是构成核酸的基本单元,有关核酸碱基结构的研究是核酸研究工作的重要基础。本研究借助于表面增强拉曼散射技术,对不同pH值条件下腺嘌呤分子在金表面的吸附构型及其变化特征进行了研究。研究结果表明,随着溶液酸性的增强、腺嘌呤分子质子化程度的增大,腺嘌呤分子在金表面的吸附态倾向于由通过氨基和嘌呤环上7位的氮原子作为结合点的直立吸附转变为分子平躺的吸附形式。这一转变过程通过腺嘌呤的环呼吸全对称伸缩振动的特征谱峰其强度有规律的显著变化而得以表征。有关这一谱峰的增强作用可以通过表面增强拉曼散射的电荷传递(CT)机理来加以说明。

SERS Study on the Effect of Solution Acid-base Properties on Adsorption Conformation of Adenine Molecules

Nucleic acid is among the most important substances related to life.It is of great significance to study the structure,property of nucleic acid molecules as well as the interaction between them.Based upon the fact that adenice is one of the basic units of nucleic acid,study of the adenine will helps the study of nucleic acid molecules.In this research,surface enhanced Raman scattering(SERS) technique is used to obtain the information about conformation and structure changes of adenine molecules adsorbed on gold surface when solution pH was changed.The results obtained here reveal that with increasing of protonation degree of adenine molecules as a result of lowering in solution pH, the adsorotion configurations of adenine molecules on gold will transfer from its originally vertical adsorption configuration at high pH to a flat adsorption configuration at low pH.This change was characterized by the relative intensity variation of a characteristic band,which is corresponding to the totally symmetric ring breathing vibration of adenine molecules,with solution pH.Thhis adsorption configuration change can be explained by the charge transfer mechanism of SERS.This research provides us significant information about nucleic acid bases and it will help our spectroelectrochemical study of nucleic acid in the futrure.