Buss Stefan, Ketter Lukas, Brünink Dana, Schwab Dominik, Klenner Steffen, Hepp Alexander, Kösters Jutta, Schmidt Thomas J, Pöttgen Rainer, Doltsinis Nikos L, Strassert Cristian A
Institut für Anorganische und Analytische Chemie - Universität Münster, Corrensstraße 28/30, Münster 48149, Germany.
CeNTech, CiMIC, SoN - Heisenbergstraße 11, Münster 48149, Germany.
Inorg Chem. 2024 Jun 3;63(22):10114-10126. doi: 10.1021/acs.inorgchem.3c02727. Epub 2024 May 23.
In this study, it is demonstrated that the radiative rate constant of phosphorescent metal complexes can be substantially enhanced using monodentate ancillary ligands containing heavy donor atoms. Thus, the chlorido coligand from a Pt(II) complex bearing a monoanionic tridentate C^N*N luminophore ([]) was replaced by triphenylphosphane (PPh) and its heavier pnictogen congeners (i.e., PnPh to yield []). Due to the high tridentate-ligand-centered character of the excited states, the P-related radiative rate is rather low while showing a significant boost upon replacement of the P donor by heavier As- and Sb-based units. The syntheses of the three complexes containing PPh, AsPh, and SbPh were completed by unambiguous characterization of the clean products using exact mass spectrometry, X-ray diffractometry, bidimensional NMR, and Sb- spectroscopy (for []) as well as steady state and time-resolved photoluminescence spectroscopies. Hence, it was shown that the hybridization defects of the V main-group atoms can be overcome by complexation with the Pt center. Notably, the enhancement of the radiative rate constants mediated by heavier coligands was achieved without significantly influencing the character of the excited states. A rationalization of the results was achieved by TD-DFT. Even though the Bi-based homologue was not accessible due to phenylation side reactions, the experimental data allowed a reasonable extrapolation of the structural features whereas the hybridization defects and the excited state properties related to the Bi-species and its phosphorescence rate can be predicted by theory. The three complexes showed an interesting antiprotozoal activity, which was unexpectedly notorious for the P-containing complex. This work could pave the road toward new efficient materials for optoelectronics and novel antiparasitic drugs.
在本研究中，结果表明，使用含有重供体原子的单齿辅助配体可显著提高磷光金属配合物的辐射速率常数。因此，带有单阴离子三齿C^N*N发光体（[]）的Pt（II）配合物中的氯配体被三苯基膦（PPh）及其较重的氮族同系物（即PnPh，以生成[]）取代。由于激发态具有以三齿配体为中心的高特征，基于P的辐射速率相当低，而当用较重的基于As和Sb的单元取代P供体时，辐射速率显著提高。通过使用精确质谱、X射线衍射、二维核磁共振和Sb光谱（用于[]）以及稳态和时间分辨光致发光光谱对纯净产物进行明确表征，完成了含有PPh、AsPh和SbPh的三种配合物的合成。因此，结果表明，通过与Pt中心络合可以克服V主族原子的杂化缺陷。值得注意的是，较重配体介导的辐射速率常数的提高是在不显著影响激发态特征的情况下实现的。通过TD-DFT对结果进行了合理化解释。尽管由于苯基化副反应无法获得基于Bi的同系物，但实验数据允许对结构特征进行合理外推，而与Bi物种及其磷光速率相关的杂化缺陷和激发态性质可以通过理论预测。这三种配合物表现出有趣的抗原生动物活性，含P的配合物的这种活性出人意料地显著。这项工作可为新型高效光电子材料和新型抗寄生虫药物铺平道路。
