5-甲基-2-硫代尿嘧啶紫外和振动光谱研究  

Research on UV and Vibrational Spectrum of 5-methy-2-thiouracil

作　　者：王曼[1] 赵彦英[1] 

机构地区：[1]浙江理工大学理学院化学系,杭州310018

出　　处：《浙江理工大学学报（自然科学版）》2013年第4期609-615,共7页Journal of Zhejiang Sci-Tech University(Natural Sciences)

摘　　要：采用密度泛函理论计算获得了5-甲基-2-硫代尿嘧啶(5M2TU)在气相和导体极化连续介质模型(CPCM)中的光谱,通过与FT-Raman实验光谱进行比较,发现加上溶剂模型的计算的拉曼光谱与实验比较吻合。获得了5M2TU在水、甲醇和乙腈中的紫外吸收光谱,发现在不同溶剂中吸收带会发生不同程度的位移。开展了5M2TU的紫外光谱指认,指认了在乙腈溶剂中200～330nm范围内的三个吸收带分别为πH→π*L,πH→π*L+1和πH-2→π*L+1的跃迁。在B3LYP/6-311++G(d,p)水平上,采用CPCM溶剂模型(水溶剂中)优化了5M2TU-nH2O(n=1,2)可能的稳定结构,并获得了它们的计算振动频率。研究结果表明偶极耦合和氢键作用是导致C=O伸缩振动频率向低波数位移的主要原因。This paper obtains the spectrum of 5-methy-2-thiouracil（SM2TU） in gaseous phase and conductor continuum polarized media model（CPCM） through calculation with Density Functional Theory~ finds through the comparison with FT-Raman experimental spectrum that Raman spectrum with the calcu- lation of solvent model matches with the experiment; obtains UV absorption spectra of 5M2TU in water, methyl alcohol and acetonitrile; finds that absorption band will have different degrees of displacement in different solvents; conducts UV spectrum identification of 5M2TU and identifies that three absorption bands within the scope of 200~330 nm in acetonitrile solvent are respectivelyπ-π,πH-πL＋1 and πH-2πL＋1 transition; optimizes the possible stable structure of5M2TU-nH20（n=1,2） with CPCM solvent model （in aqueous solution） at B3LYP/6-311＋q-G（d, p） level and obtains their calculated vibrational frequency. The research structure indicates that dipolar coupling and hydrogen-bond interaction are main reasons causing the shift of C=O stretching vibrational frequency towards lower wave number.

关 键 词：5-甲基-2-硫代尿嘧啶 紫外吸收光谱 羰基伸缩振动 密度泛函理论计算 

分 类 号：O643.15[理学—物理化学]