Small chalcogen-organyls - fundamental structural, conformational and electronic properties

官能团思维是化学中最成功的概念之一。因此，对它们的性质的详细了解是这个主题的核心。这个德国-阿根廷合作项目的总体目标是获得基本模型化合物的结构和物理性质的详细知识，其中硫属元素官能团与具有可变电子性质的小烷基或甲硅烷基键合。这允许在隔离其他影响的情况下调查小的结构单元，并应用多方法方法。该项目的重点是结构，构象和光谱特性的变化，这取决于取代基的电子变化，但也取决于相（气/液/固）。主要目标是了解分子内效应，包括异头（立体电子），空间，内消旋和诱导异构效应以及分子间相互作用。研究的对象包括硫氰酸酯（RSCN）和异硫氰酸酯（RNCS）、亚硫基羰基（RSC（O）X）二硫化物（RSSR）、亚硫腈（R-SNO）、全氟烷基亚硫酰基（RS（O）X）和全氟硒基（RSe（O）X）化合物、全氟烷基硫代羰基（RS（S）X）和全氟烷酰基卤（RC（O）X），并系统地评价了取代基效应，即R =烷基、全氟烷基、和各种甲硅烷基，X =卤素、仲卤素、甲氧基或拟卤素取代基（F、Cl、Br、CN、I、N3、CF 3、CH 3 O）。该方法基于气相和固相中的分子结构的确定（通过气体电子衍射、振动光谱包括基质隔离光谱、原位结晶和X射线衍射、电子密度确定和拓扑分析），通过与计算结果的同时比较来支持。与来自汉诺威和北京的合作伙伴合作，可以进行微波、气相紫外-可见、光电子能谱和光电离质谱研究，从而提供有关结构和键合的更多信息。在某些情况下，LNLS（巴西）和SOLEIL（法国）的同步加速器设施可用于从其现有的原子光谱学中获得知识。这种真正的多方法方法产生了实验信息和理论模型的非常有效和创造性的协同作用，并确保了结果的可靠性和对重要参比化合物的键合和相互作用的高层次多方面理解。

Thinking in functional groups is one of the most successful concepts in chemistry. A detailed understanding of their properties is therefore at the heart of this subject. The overall aim of this German-Argentinean collaboration project is to gain detailed knowledge of structural and physical properties of fundamental model compounds, in which chalcogen-functional groups are bonded to small alkyl or silyl groups with variable electronic properties. This allows investigating small structural units in isolation of other effects and applying a multi-method approach. The project focuses on changes in structure, conformation and spectroscopic pro-per¬ties depending on electronic variation of the substituents, but also on the phase (gas/liquid/solid). An understanding of intramolecular effects, including anomeric (stereo-electronic), steric, mesomeric and inductomeric effects as well as intermolecular interactions are the main objectives. The objects of study include thiocyanates (RSCN) and isothiocyanates (RNCS), sulfenylcarbonyls (RSC(O)X) disulphides (RSSR), thionitrites (R-SNO), perfluoroalkylsulfinyl (RS(O)X) and -selenyl (RSe(O)X) compounds, perfluoroalkylthiocarbonyl (RS(S)X) and perfluoroalkanoyl halides of the type (RC(O)X), with a systematic evaluation of substituent effects, i.e. R = alkyl, perfluoralkyl, and various silyl and X = halogen, parahalogen, methoxy or pseudohalogen substituents (F, Cl, Br, CN, I, N3, CF3, CH3O). The methodology is based on determination of molecular struc¬tu¬res in the gas and solid phases (by means of gas electron-diffraction, vibrational spectroscopy including matrix isolation spectroscopy, in-situ crys¬tallisation & X-ray diffraction, electron density determination and topology analysis), backed by simul¬ta¬ne¬ous comparison with computational results. Cooperation with partners from Hannover and Beijing allows additionally performing microwave, gas-phase UV-vis, photoelectron spectroscopy and photoionization mass spectrometry investigations, hence providing further information on structure and bonding. In selected cases LNLS (Brazil) and SOLEIL (France) synchrotron facilities may be used to gain knowledge from their available atomic spectroscopies. This true multi-method approach gives rise to a very potent and creative synergy of both experimental information and theoretical models and assures the reliability of results and a high-level multifaceted understanding of bonding and interactions of important reference compounds.