Excitation-Wavelength-Dependent and Auxiliary-Ligand-Tuned Intersystem-Crossing Efficiency in Cyclometalated Platinum(II) Complexes: Spectroscopic and Theoretical Studies
作者:Kai Li、Glenna So Ming Tong、Jia Yuan、Chensheng Ma、Lili Du、Chen Yang、Wai-Ming Kwok、David Lee Phillips、Chi-Ming Che
DOI:10.1021/acs.inorgchem.0c01192
日期:2020.10.19
decreases the energy gap of the coupling excited states, leading to a decrease in the activation energy and an increase in spin–orbit coupling. Furthermore, the ISC rate constants of [Pt(thpy)(P^P)]+ complexes are found to depend on the excitation wavelengths. The deviation from Kasha–Vavilov’s rule upon photoexcitation at λexc < 350 nm is due to the ultrafast S2 → T2 and S2 → T3 ISCs, as demonstrated by
了解影响过渡金属配合物的系统间交叉(ISC)速率常数(k ISC)的因素对于具有定制光物理性质的材料设计至关重要。迄今为止,有关ISC的大多数工作都集中在发色配体的影响和对ISC效率的理解上,主要是从稳态荧光与磷光强度比和基态计算中得出的,仅进行了一些高级计算在k ISC上,将激发态结构变化和溶剂重组考虑在内,以便与实验数据进行定量比较。在这项工作中,一系列的[Pt(thpy)X)] +制备了复合物[Hthpy = 2-(2'-噻吩基)吡啶,其中X =辅助配体],并通过稳态和时间分辨发光光谱学表征。已经使用了一组具有不同的σ-给体/π-接受特性的辅助配体。为了比较,还检查了[Pt(ppy)(P ^ P)] +(Hppy = 2-苯基吡啶和P ^ P =二膦配体)的类似物。[Pt(thpy)(P ^ P)] +配合物表现出双重荧光-磷光发射,其ISC速率常数随辅助配体的电子特性而变化:给电子的配体越多,从激发的S