Coherent Vibration and Femtosecond Dynamics of the Platinum Complex Oligomers upon Intermolecular Bond Formation in the Excited State
Munetaka Iwamura, Airi Fukui, Koichi Nozaki, Hikaru Kuramochi, Satoshi Takeuchi, Tahei Tahara
Abstract
Abstract Femtosecond time‐resolved absorption and picosecond time‐resolved emission measurements were carried out for highly concentrated aqueous solutions of K 2 [Pt(CN) 4 ] to investigate excited‐state dynamics of the [Pt(CN) 4 2− ] oligomers formed with metallophilic interactions. Time‐resolved absorption spectra exhibit complicated dynamics that are represented with five time constants. Among them, the 90‐ps and 400‐ps dynamics were assigned to the S 1 → T 1 intersystem crossing of the trimer and tetramer coexisting in the solution by comparison with the fluorescence decays. Clear oscillations of transient absorption were observed in the first few picoseconds, and the frequency‐detected‐wavelength 2D analysis revealed that the 135‐cm −1 and 65‐cm −1 oscillations arise from the Pt–Pt stretch motions of the S 1 trimer and S 1 tetramer, respectively. The obtained time‐resolved spectroscopic data provide a clear view of the excited‐state dynamics of the [Pt(CN) 4 2− ] oligomers in the femto‐/picosecond time region.