Lehrstuhl für Physikalische Chemie 2, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058, Erlangen, Germany.
Lehrstuhl für Chemische Reaktionstechnik, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058, Erlangen, Germany.
Chemphyschem. 2023 Jan 17;24(2):e202200391. doi: 10.1002/cphc.202200391. Epub 2022 Oct 20.
We studied the formation and surface behavior of Pt(II) and Pd(II) complexes with ligand systems derived from two nitrile-functionalized ionic liquids (ILs) in solution using angle-resolved X-ray photoelectron spectroscopy (ARXPS). These ligand systems enabled a high solubility of the metal complexes in IL solution. The complexes were prepared by simple ligand substitution under vacuum conditions in defined excess of the coordinating ILs, [C CNC Im][Tf N] and [C CNC Pip][Tf N], to immediately yield solutions of the final products. The ILs differ in the cationic head group and the chain length of the functionalized substituent. Our XPS measurements on the neat ILs gave insights in the electronic properties of the coordinating substituents revealing differences in donation capability and stability of the complexes. Investigations on the composition of the outermost surface layers using ARXPS revealed no surface affinity of the nitrile-functionalized chains in the neat ILs. Solutions of the formed complexes in the nitrile ILs showed homogeneous distribution of the solute at the surface with the heterocyclic moieties preferentially orientated towards the vacuum, while the metal centers are rather located further away from the IL/vacuum interface.
我们使用角分辨 X 射线光电子能谱（ARXPS）研究了源自两种腈基功能化离子液体（IL）的配体系统的 Pt（II）和 Pd（II）配合物在溶液中的形成和表面行为。这些配体系统使金属配合物在 IL 溶液中有很高的溶解度。配合物是通过在真空条件下用配位 IL（[C CNC Im][Tf N]和[C CNC Pip][Tf N]）过量简单的配体取代制备的，立即得到最终产物的溶液。IL 在阳离子头基和功能化取代基的链长上有所不同。我们对纯 IL 的 XPS 测量提供了关于配位取代基电子性质的见解，揭示了配合物的供电子能力和稳定性的差异。使用 ARXPS 对最外层表面层的组成进行的研究表明，在纯 IL 中，腈基链没有表面亲和力。在腈 IL 中形成的配合物溶液在表面上显示出溶质的均匀分布，杂环部分优先朝向真空取向，而金属中心则离 IL/真空界面更远。
