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，详细了解它们的性质是本学科的核心。这个德国-阿根廷合作项目的总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，其中含硫基团与具有可变电子性质的小烷基或硅基结合。这允许在隔离其他影响的情况下研究小型结构单元，并应用多方法方法。该项目侧重于结构、构象和光谱性质的变化，这取决于取代基的电子变化，也取决于相（气/液/固）。分子内效应的理解，包括分子间相互作用的异构（立体电子），空间，中间体和诱导体效应是主要的目标。研究对象包括硫氰酸酯（RSCN）和异硫氰酸酯（RNCS）、磺酰基羰基（RSC(O)X）二硫化物（RSSR）、硫代亚硝酸盐（R- sno）、全氟烷基亚砜基（RS(O)X）和-硒基（RSe(O)X）化合物、全氟烷基硫代羰基（RS(S)X）和全氟烷酰卤化物（RC(O)X），系统评价了取代基效应，即R =烷基、全氟烷基、各种硅基和X =卤素、副卤素、甲氧基或假卤素取代基(F、Cl、Br、CN、I、N3、CF3、CH3O)。该方法基于气相和固相分子结构的测定（通过气体电子衍射，振动光谱，包括基质分离光谱，原位结晶和x射线衍射，电子密度测定和拓扑分析），并同时与计算结果进行比较。与来自汉诺威和北京的合作伙伴合作，可以进行额外的微波、气相紫外可见、光电子能谱和光电离质谱研究，从而提供进一步的结构和键合信息。在选定的情况下，LNLS（巴西）和SOLEIL（法国）同步加速器设施可用于从其可用的原子光谱中获得知识。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考化合物的键合和相互作用的高层次的多方面理解。

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.