Vibrational spectral investigation on xanthine and its derivatives-theophylline, caffeine and theobromine
Vibrational spectral investigation on xanthine and its derivatives-theophylline, caffeine and theobromine
复制标题
DOI：
10.1016/j.saa.2004.03.030
复制
发表时间：
2005-01-01
影响因子：
4.4
通讯作者：
Ponnusamy, S
中科院分区：
文献类型：
--
作者：
Gunasekaran, S;Sankari, G;Ponnusamy, S
对黄嘌呤、咖啡因、茶碱和可可碱四种具有相似环结构但侧链取代不同的化合物进行了正态坐标分析。黄嘌呤的化学名称为2,6-二羟基嘌呤。咖啡因、茶碱和可可碱是甲基化黄嘌呤。考虑到甲基作为点质量，基于与结构相关的 C-s 点群对称性，振动简正模态的数量可以分布为 Gamma(vib) = 27 A' + 12 A"。在本工作中，考虑了 15 A' 和 12 A" 简正模态。构建了一组新的正交对称坐标。法向坐标分析采用Wilson F-G矩阵法。通过使用化合物的 FTIR 和 FT Raman 光谱，得到了令人满意的振动带分配。势能分布是用力常数的到达值计算的，因此已经检查了频率分配的一致性。 (C) 2004 Elsevier B.V. 保留所有权利。
A normal coordinate analysis has been carried out on four compounds having a similar ring structure with different side chain substitutions, which are xanthine, caffeine, theophylline, and theobromine. Xanthine is chemically known as 2,6-dihydroxy purine. Caffeine, theophylline and theobromine are methylated xanthines. Considering the methyl groups as point mass, the number of normal modes of vibrations can be distributed as Gamma(vib) = 27 A' + 12 A" based on C-s point group symmetry associated with the structures. In the present work 15 A' and 12 A" normal modes are considered. A new set of orthonormal symmetry co-ordinates have been constructed. Wilson's F-G matrix method has been adopted for the normal coordinate analysis. A satisfactory vibrational band assignment has been made by employing the FTIR and FT Raman spectra of the compounds. The potential energy distribution is calculated with the arrived values of the force constants and hence the agreement of the frequency assignment has been checked. (C) 2004 Elsevier B.V. All rights reserved.