Singh Swapnil, Singh Harshita, Karthick T, Tandon Poonam, Dethe Dattatraya H, Erande Rohan D
Department of Physics, University of Lucknow.
Anal Sci. 2017;33(1):99-104. doi: 10.2116/analsci.33.99.
In the present work, structural and spectroscopic investigations were carried out on a borreverine derivative. Borreverine is a class of alkaloid as well a natural antimalarial drug extracted from Borreria verticillata. With the aim of finding possible conformers, a detailed conformational analysis of a borreverine derivative was conducted utilizing density functional theory employing the B3LYP/6-31G(d,p) method. The crystallographic geometry was used for full geometry optimization, followed by a conformational analysis. The conformational investigation predicted the most stable conformer (conformer I), which was further compared with the initial crystallographic geometry (conformer V). The geometry optimization, vibrational frequency, and intensity of these two conformers (I and V) were calculated in the ground state using density functional theory with the B3LYP functional and 6-31G(d,p) basis set. The spectroscopic investigation was conducted using Fourier transform infrared (FT-IR) and Fourier transform Raman (FT-Raman) techniques. Tentative vibrational assignments of some selective modes were presented utilizing the observed FT-IR, FT-Raman, and calculated spectra. The scaled and observed wavenumbers were found to be in good agreement. The molecular electrostatic potential was computed and plotted so as to elucidate the reactive sites of the molecule. Natural bond orbital studies were performed to investigate the intramolecular charge transfer that results in molecular stability.
在本研究中，对一种波瑞维林衍生物进行了结构和光谱研究。波瑞维林是一类生物碱，也是从轮叶耳草中提取的一种天然抗疟药物。为了找到可能的构象异构体，利用密度泛函理论采用B3LYP/6-31G(d,p)方法对一种波瑞维林衍生物进行了详细的构象分析。晶体学几何结构用于全几何优化，随后进行构象分析。构象研究预测了最稳定的构象异构体（构象异构体I），并将其与初始晶体学几何结构（构象异构体V）进行了进一步比较。使用密度泛函理论结合B3LYP泛函和6-31G(d,p)基组在基态下计算了这两种构象异构体（I和V）的几何优化、振动频率和强度。使用傅里叶变换红外（FT-IR）和傅里叶变换拉曼（FT-拉曼）技术进行了光谱研究。利用观察到的FT-IR、FT-拉曼和计算光谱对一些选择性模式进行了初步的振动归属。发现缩放后的波数与观察到的波数吻合良好。计算并绘制了分子静电势，以阐明分子的反应位点。进行了自然键轨道研究，以研究导致分子稳定性的分子内电荷转移。
