Laboratoire Matériaux Molécules et Applications, IPEST, Université de Carthage, Route Sidi Bou Said, La Marsa, Tunisie.
Faculté des Sciences de Bizerte, Université de Carthage, Bizerte, Tunisie.
PLoS One. 2018 Nov 19;13(11):e0207635. doi: 10.1371/journal.pone.0207635. eCollection 2018.
Since the early nineties, countless publications have been devoted to the study of possible uses of [60] fullerene (C60) and its derivatives in the fields of materials and nano-biomedical sciences. However, in spite of the importance of conformers notably from the pharmacological point of view, the cis/trans isomerization of C60 mono-adducts has been rarely seldom investigated. Here we present the results of DFT calculations of the structural, vibrational and NMR properties of both cis and trans isomers of fulleropyrrolidine mono-adduct obtained by photo-addition of glycine methyl ester to C60. Taken together, our results have shown that the cis isomer is more stable than the trans one. For the cis conformation, the simulated vibrational spectrum shows a more intense peak at 1298 cm-1. While 13C spectra revealed no significant differences between the two isomers as compared to experimental results, the calculated 1H chemical shifts show a significant difference between the two conformers in both the gas phase and in solution. The trans isomer presents a proton at 5.86 ppm, which is more deshielded than the proton of the cis conformer (5.24 ppm).
自 90 年代初以来，已有无数出版物致力于研究 [60] 富勒烯（C60）及其衍生物在材料和纳米生物医学科学领域的可能用途。然而，尽管顺/反异构体在药理学方面的重要性不可忽视，但 C60 单加成物的顺反异构化很少得到研究。在这里，我们介绍了通过甘氨酸甲酯与 C60 的光加成反应得到的富勒吡咯啉单加成物的顺式和反式异构体的结构、振动和 NMR 性质的 DFT 计算结果。总的来说，我们的结果表明顺式异构体比反式异构体更稳定。对于顺式构象，模拟的振动光谱在 1298 cm-1 处显示出更强的峰。虽然 13C 光谱与实验结果相比，两种异构体之间没有明显差异，但计算的 1H 化学位移表明两种构象在气相和溶液中均存在显著差异。反式异构体的质子出现在 5.86 ppm，比顺式异构体的质子（5.24 ppm）更去屏蔽。
