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首页> 外文期刊>Spectrochimica acta, Part A. Molecular and biomolecular spectroscopy >A Raman and infrared study of 1-furoyl-3-monosubstituted and 3,3-disubstituted thioureas
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A Raman and infrared study of 1-furoyl-3-monosubstituted and 3,3-disubstituted thioureas

机译：1-呋喃基-3-单取代和3,3-二取代硫脲的拉曼和红外研究

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Raman and IR spectra of two series of 1-furoylthiourea derivatives (19 compounds) were recorded and compared in order to identify the vibrations, which involve contributions from motions within the thioureido (NCSN) core. This procedure allowed an unequivocal identification of the v(C=S) vibration in these spectra. In 3-monosubstituted furoylthioureas (Series 2) the carbonyl group and the proton on N-3 are engaged in a strong hydrogen bond interaction. This leads to an "S"-shaped conformation of the C=O and C=S groups where these donor sites reach a maximum separation. In this conformation, the v(C=O) vibration is not influenced by the substituent. In the absence of that hydrogen bridge, in 3,3-disubstituted thiourea derivatives (Series 1), the C=O and C=S groups adopt an "U"-shaped conformation. In this conformation, the v(C=O) vibration shows a pronounced substituent dependence. These thiourea derivatives have been tested as ionophores for heavy-metal ion selective electrodes and their behavior in that sense correlates with the observed Raman and IR absorptions. The best performance in that application corresponds to compounds of Series 2, which showed the highest frequency values of the v(C=S) vibration. This fact was related to an appropriated nucleophilic character of the sulphur atom. From these data, Raman and IR spectra of these thiourea derivatives could be used as a predictor on their expected behavior in analytical applications as ionophores. (c) 2005 Elsevier B.V. All rights reserved.
机译：记录并比较了两个系列的1-呋喃基硫脲衍生物（19种化合物）的拉曼光谱和红外光谱，以鉴定振动，其中涉及硫脲基（NCSN）核内运动的贡献。此程序可以明确识别这些光谱中的v（C = S）振动。在3-单取代的呋喃基硫脲（系列2）中，N-3上的羰基和质子参与强氢键相互作用。这导致C ＝ O和C ＝ S基团的“ S”形构象，其中这些供体位点达到最大间隔。在该构型中，v（C ＝ O）振动不受取代基影响。在没有氢桥的情况下，在3,3-二取代的硫脲衍生物（系列1）中，C = O和C = S基团采用“ U”形构象。在此构型中，v（C = O）振动显示出明显的取代基依赖性。这些硫脲衍生物已作为重金属离子选择性电极的离子载体进行了测试，其行为与观察到的拉曼和红外吸收有关。该应用中的最佳性能对应于系列2的化合物，该系列显示出v（C = S）振动的最高频率值。这个事实与硫原子的适当亲核特性有关。根据这些数据，这些硫脲衍生物的拉曼光谱和红外光谱可以用作预测离子载体在分析应用中的预期行为的指标。 （c）2005 Elsevier B.V.保留所有权利。

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