Laboratoire de Spectroscopie Infrarouge, Département de Chimie, Faculté des Sciences, Université Mohammed V-Agdal, Avenue Ibn Batouta, Rabat, Morocco.
Spectrochim Acta A Mol Biomol Spectrosc. 2012 Nov;97:975-85. doi: 10.1016/j.saa.2012.07.052. Epub 2012 Aug 1.
The purpose of this manuscript is to discuss our investigations of diprotonated guanazolium chloride using vibrational spectroscopy and quantum chemical methods. The solid phase FT-IR and FT-Raman spectra were recorded in the regions 4000-400cm(-1) and 3600-50cm(-1) respectively, and the band assignments were supported by deuteration effects. Different sites of diprotonation have been theoretically examined at the B3LYP/6-31G level. The results of energy calculations show that the diprotonation process occurs with the two pyridine-like nitrogen N2 and N4 of the triazole ring. The molecular structure, harmonic vibrational wave numbers, infrared intensities and Raman activities were calculated for this form by DFT/B3LYP methods, using a 6-31G basis set. Both the optimized geometries and the theoretical and experimental spectra for diprotonated guanazolium under a stable form are compared with theoretical and experimental data of the neutral molecule reported in our previous work. This comparison reveals that the diprotonation occurs on the triazolic nucleus, and provide information about the hydrogen bonding in the crystal. The scaled vibrational wave number values of the diprotonated form are in close agreement with the experimental data. The normal vibrations were characterized in terms of potential energy distribution (PED) using the VEDA 4 program.
本文旨在讨论我们使用振动光谱和量子化学方法对二质子化胍鎓氯化物的研究。分别在 4000-400cm(-1) 和 3600-50cm(-1) 区域记录了固相 FT-IR 和 FT-Raman 光谱，并通过氘代效应支持了带分配。在 B3LYP/6-31G 水平上理论上检查了二质子化的不同位置。能量计算的结果表明，二质子化过程发生在三唑环的两个吡啶样氮 N2 和 N4 上。通过 DFT/B3LYP 方法，使用 6-31G 基组，计算了这种形式的分子结构、谐波振动波数、红外强度和拉曼活性。与我们之前工作中报道的中性分子的理论和实验光谱相比，对稳定形式下的二质子化胍鎓的优化几何形状和理论和实验光谱进行了比较。这种比较表明二质子化发生在三唑核上，并提供了有关晶体中氢键的信息。二质子化形式的缩放振动波数值与实验数据非常吻合。使用 VEDA 4 程序，根据势能分布（PED）对正则振动进行了特征化。
