Photoinduced Dynamics of Bis-dipyrrinato-palladium(II) and Porphodimethenato-palladium(II) Complexes: Governing Near Infrared Phosphorescence by Structural Restriction.
Photoinduced Dynamics of Bis-dipyrrinato-palladium(II) and Porphodimethenato-palladium(II) Complexes: Governing Near Infrared Phosphorescence by Structural Restriction.
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DOI：
10.1021/acs.inorgchem.8b00974
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发表时间：
2018-06
影响因子：
4.6
通讯作者：
S. Riese;M. Holzapfel;A. Schmiedel;Ingo Gert;D. Schmidt;F. Würthner;C. Lambert
中科院分区：
文献类型：
--
作者：
S. Riese;M. Holzapfel;A. Schmiedel;Ingo Gert;D. Schmidt;F. Würthner;C. Lambert
虽然表面上相似，双二吡咯合钯（II）配合物1和桥接porphodimethenato-palladium（II）配合物2具有显着不同的结构，在基态（由X射线结构分析证明）和在单重态和三重态激发态（由密度泛函理论方法计算）。虽然配合物2是相当刚性的，但配合物1在激发态下经历了主要的结构重组以产生双楔型（跷跷板）三重态。激发态的动力学探测瞬态吸收光谱与飞秒和纳秒的时间分辨率和荧光上转换和产额系统间穿越速率常数的钙。（13-16 ps）-1。在流体溶液中观察到络合物2中显着的近红外磷光，但络合物1中没有任何发射，这可以通过1的结构重组来合理化，这导致非发射三重态金属中心态。
Although superficially similar, the bis-dipyrrinato-palladium(II) complex 1 and the bridged porphodimethenato-palladium(II) complex 2 possess dramatically different structures in the ground state (proved by X-ray structure analysis) and in the singlet and triplet excited states (calculated by density functional theory methods). While complex 2 is rather rigid, complex 1 undergoes a major structural reorganization in the excited state to yield a disphenoidal (seesaw) triplet state. The dynamics of the excited states were probed by transient absorption spectroscopy with femtosecond and nanosecond time resolution and with fluorescence upconversion and yield intersystem crossing rate constants of ca. (13-16 ps)-1. The observation of significant near infrared phosphorescence in complex 2 but the absence of any emission in complex 1 in fluid solution could be rationalized by the structural reorganization of 1 which results in a nonemissive triplet metal centered state.