Transition metal compounds as probes for ionic liquid acidity

当使用离子液体作为溶剂时，溶剂化行为至关重要。人们已经认识到，“物以类聚”这一经验法则仅对盐类不太适用，因为许多盐类对其他盐的溶解度相当差。从微观角度看，所有溶剂-溶质相互作用都可以看作是供体-受体相互作用的特殊情况。从这个角度看，刘易斯酸度（电子接受功率）和碱度（电子给体功率）变得很重要。通过d-和f-金属化合物探测离子液体的受体和供体功率来研究离子液体的酸性和碱性，从而建立阳离子酸性和阴离子碱性的独立尺度。对于离子液体，预计阳离子是主要的酸性，接受电子功能，而阴离子是主要的碱性，提供电子功能。在过去的资助期内，我们成功地建立了几种独立的方法来探测il的酸碱性质，使用紫外-可见吸收和发光光谱以及电化学（循环伏安法）。我们现在想将成功的方法扩展到更广泛的il中，以测试我们的方法，以充分利用它们的功能和局限性。特别注意的是，在IL离子上携带捐赠基团的IL将如何影响IL的整体碱性，这通常取决于IL阴离子，反之亦然。研究将通过基于振动光谱（拉曼）的方法完成。最终目标是在项目结束时，通过将我们的结果和其他人（在SPP内部和外部）的结果放在一起，获得离子液体酸度的一致和连贯的图像。

Whenever using ionic liquids as solvents, the solvation behaviour is of vital importance. It has been realized that the rule of thumb “like dissolves like” only poorly holds true for ILs as many ILs show rather poor solubilities for other salts. In a microscopic view all solvent-solute interactions can be looked at as special cases of donor-acceptor interactions. In this sight the Lewis acidity (electron acceptor power) and basicity (electron donor power) becomes important. It is the goal to investigate the acidity and basicity of ionic liquids by probing their acceptor and donor power through d- and f-metal compounds to establish independent scales for cation acidities and anion basicities. For ionic liquids it is anticipated that the cation is the primary acidic, electron accepting functionality whereas the IL anion is the main basic, electron donating functionality. In the past funding period we successfully established several independent methods to probe ILs for their acid-base character using UV-Vis absorption and luminescence spectroscopy as well as electrochemistry (cyclic voltammetry). We would now like to extend the successful methods to a wide range of ILs to test our methods to fully access their power and limitations. Special attention will be directed on how ILs bearing donating groups on the IL cation will influence the overall IL basicity which usually depends on the IL anion, and vice versa. Studies will be completed by methods based on vibrational spectroscopy (Raman). The final aim is to obtain a consistent and coherent picture of ionic liquid acidity by putting our results and those of others (inside and outside the SPP) together at the end of the program.