The study of substitution effects on the structural and vibrational properties of a series of recently reported mono fluoro-substituted sulfinylanilines proceeds a step forward with the present study of 3,4-difluorosulfinylaniline and 2,3,4-trifluorosulfinylaniline. These substances were synthesized and characterized by FTIR, Raman and NMR spectra, which were subsequently compared with theoretical spectra, obtained by quantum chemical calculations at different levels of theory. The number of signals in the vibrational spectra, together with the analysis of the potential energy surface of both compounds reveal the presence of stable conformers possessing the angular NS→O group in a syn conformation of the CN and S→O bonds and coplanar with the ring plane. According to the Natural Bond Orbital analysis performed, the prevalence of a given structure of the stable syn conformer over other local minima of the potential energy surface obtained upon rotation around the NS and CN bonds is a consequence of different orbital interactions. The planar conformation predicted for stable minima are stabilized by conjugation between the π-systems of the NS→O group and the ring and by a weak orbital interaction between oxygen and the ortho hydrogen closest to it.

对取代作用对一系列最近报道的单氟取代的亚磺酰基苯胺的结构和振动性能的研究，使本研究3,4-二氟亚磺酰基苯胺和2,3,4-三氟亚磺酰基苯胺的研究向前迈进了一步。合成了这些物质，并通过FTIR，拉曼光谱和NMR光谱对其进行了表征，然后将其与通过在不同理论水平上的量子化学计算获得的理论光谱进行了比较。振动光谱中的信号数量以及对这两种化合物的势能表面的分析表明，存在稳定的构象异构体，该构象异构体在C的顺式构象中具有角N S→O基团。N和S→O键与环平面共面。根据进行的自然键轨道分析，稳定的顺式构象异构体给定结构在围绕N S和C N键旋转时获得的势能面的其他局部最小值的普遍性是不同轨道相互作用的结果。N S→O基团的π系统与环之间的共轭以及氧与最接近它的邻氢之间的弱轨道相互作用，可以稳定稳定的极小值。