Ultrafast Excited-State Dynamics of Photoluminescent Pt(II) Dimers Probed by a Coherent Vibrational Wavepacket
Ultrafast Excited-State Dynamics of Photoluminescent Pt(II) Dimers Probed by a Coherent Vibrational Wavepacket
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DOI：
10.1021/acs.jpclett.1c01289
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发表时间：
2021-07-16
影响因子：
5.7
通讯作者：
Chen, Lin X.
中科院分区：
文献类型：
--
作者：
Kim, Pyosang;Valentine, Andrew J. S.;Chen, Lin X.
一些过渡金属配合物（tmc）复杂的势能面（PESs）对绘制可能影响光化学结果的初始激发态路径提出了挑战。通过检测四种结构相关铂（II）二聚物在金属-金属-配体-电荷转移激发态下Pt-Pt拉伸模式的相干振动波包（CVWP）运动，研究了它们的超快系统间交叉（ISC）动力学。通过飞秒瞬态吸收光谱捕捉结构相关的CVWP行为（频率、脱相时间和振荡幅度），通过短时傅立叶变换进行分析，并通过量子力学计算进行合理化，揭示了双重ISC途径。结果表明，配体可以通过微调PESs来影响激发态与frank - condon态的锥形交叉点的接近程度，从而控制双ISC通路的分支比例。这项比较研究为通过配体结构控制tmc的激发态轨迹提供了未来的机会。
Intricate potential energy surfaces (PESs) of some transition metal complexes (TMCs) pose challenges in mapping out initial excited-state pathways that could influence photochemical outcomes. Ultrafast intersystem crossing (ISC) dynamics of four structurally related platinum(II) dimer complexes were examined by detecting their coherent vibrational wavepacket (CVWP) motions of Pt-Pt stretching mode in the metal-metal-to-ligand-charge-transfer excited states. Structurally dependent CVWP behaviors (frequency, dephasing time, and oscillation amplitudes) were captured by femtosecond transient absorption spectroscopy, analyzed by short-time Fourier transformation, and rationalized by quantum mechanical calculations, revealing dual ISC pathways. The results suggest that the ligands could fine-tune the PESs to influence the proximity of the conical intersections of the excited states with the Franck-Condon state and thus to control the branching ratio of the dual ISC pathways. This comparative study presents future opportunities in control excited-state trajectories of TMCs via ligand structures.