Rentschler Martin, Schmid Marie-Ann, Frey Wolfgang, Tschierlei Stefanie, Karnahl Michael
Institute of Organic Chemistry, University of Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany.
Institute of Inorganic Chemistry I, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany.
Inorg Chem. 2020 Oct 19;59(20):14762-14771. doi: 10.1021/acs.inorgchem.9b03687. Epub 2020 Mar 26.
To bind or not to bind: Driven by the motivation to increase the (photo)stability of traditional Cu(I) photosensitizers, multidentate diimine ligands, which contain two additional donor sites, were designed. To this end, a systematic series of four 1,10-phenanthroline ligands with either OR or SR (R = Pr or Ph) donor groups at the 2 and 9 positions and their resulting hetero- and homoleptic Cu(I) complexes were prepared. In addition, the related Ru(II) complexes were also synthesized to study the effect of another metal center. In the following, a combination of NMR spectroscopy and X-ray analysis was used to evaluate the impact of the additional donor moieties on the coordination behavior. Most remarkably, for the homoleptic bis(diimine)copper(I) complexes, a pentacoordinated copper center, corresponding to a (4 + 1)-fold coordination mode, was found in the solid state. This additional binding is the first indication that the extra donor might also occupy a free coordination site in the excited-state complex, modifying the nature of the excited states and their respective deactivation processes. Therefore, the electrochemical and photophysical properties of all novel complexes (in total 13) were studied in detail to assess the potential of these photosensitizers for future applications within solar energy conversion schemes. Finally, the photostabilities and a potential degradation mechanism were analyzed for representative samples.
受提高传统Cu(I)光敏剂（光）稳定性的动机驱使，设计了含有两个额外供体位点的多齿二亚胺配体。为此，制备了一系列系统的四个1,10 - 菲咯啉配体，它们在2和9位带有OR或SR（R = Pr或Ph）供体基团以及由此产生的杂配和同配Cu(I)配合物。此外，还合成了相关的Ru(II)配合物以研究另一种金属中心的影响。接下来，结合核磁共振光谱和X射线分析来评估额外供体部分对配位行为的影响。最值得注意的是，对于同配双（二亚胺）铜(I)配合物，在固态中发现了一个五配位铜中心，对应于(4 + 1)重配位模式。这种额外的配位是第一个迹象，表明额外的供体在激发态配合物中也可能占据一个自由配位位点，从而改变激发态的性质及其各自的失活过程。因此，详细研究了所有新型配合物（总共13种）的电化学和光物理性质，以评估这些光敏剂在太阳能转换方案中未来应用的潜力。最后，对代表性样品的光稳定性和潜在降解机制进行了分析。
