Spectroscopic investigation on cocrystal formation between adenine and fumaric acid based on infrared and Raman techniques
Spectroscopic investigation on cocrystal formation between adenine and fumaric acid based on infrared and Raman techniques
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基于红外和拉曼技术的腺嘌呤与富马酸共晶形成的光谱研究
DOI：
10.1016/j.saa.2015.09.020
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发表时间：
2016-01-15
影响因子：
4.4
通讯作者：
Hong, Zhi
中科院分区：
文献类型：
--
作者：
Du, Yong;Fang, Hong Xia;Hong, Zhi
腺嘌呤作为双链DNA的重要组成部分，由于其分子结构中存在丰富的氢键供体和受体，因而具有强大的氢键能力。因此，利用分子间氢键效应，腺嘌呤与其它小分子之间容易形成共晶。本文以腺嘌呤和富马酸的共晶为模型体系，用傅里叶变换红外光谱和拉曼光谱技术对其进行了表征。实验结果表明，腺嘌呤与富马酸形成的晶体具有独特的光谱特征。采用密度泛函理论（DFT）方法对腺嘌呤、富马酸及其共晶的分子结构进行了优化，并模拟了它们的振动模式。结合理论和实验振动结果，发现共晶形成后，共晶内氨基和羰基的弯曲和伸缩振动特征带向低频移动，相应的键长也有所增加.根据DFT模拟结果，对实验光谱中的不同振动模式进行了归属。该研究可为利用振动光谱技术表征活性成分与共晶形成剂之间形成的共晶以及共晶形成过程中的分子间氢键效应提供实验和理论依据。(C)2015 Elsevier B.V.版权所有。
As an important component of double-stranded DNA, adenine has powerful hydrogen-bond capability, due to rich hydrogen bond donors and acceptors existing within its molecular structure. Therefore, it is easy to form cocrystal between adenine and other small molecules with intermolecular hydrogen-bond effect. In this work, cocrystal of adenine and fumaric acid has been characterized as model system by FT-IR and FT-Raman spectral techniques. The experimental results show that the couystal formed between adenine and fumaric acid possesses unique spectroscopical characteristic compared with that of starting materials. Density functional theory (DFT) calculation has been performed to optimize the molecular structures and simulate vibrational modes of adenine, fumaric acid and the corresponding cocrystal. Combining the theoretical and experimental vibrational results, the characteristic bands corresponding to bending and stretching vibrations of amino and carbonyl groups within cocrystal are shifted into lower frequencies upon cocrystal formation, and the corresponding bond lengths show some increase due to the effect of intermolecular hydrogen bonding. Different vibrational modes shown in the experimental spectra have been assigned based on the simulation DFT results. The study could provide experimental and theoretical benchmarks to characterize cocrystal formed between active ingredients and cocrystal formers and also the intermolecular hydrogen-bond effect within cocrystal formation process by vibrational spectroscopic techniques. (C) 2015 Elsevier B.V. All rights reserved.