Near-IR Broadband-Absorbing trans-Bisphosphine Pt(II) Bisacetylide Complexes: Preparation and Study of the Photophysics

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• 作者：Wenbo Yang ; Ahmet Karatay ; Jianzhang Zhao ; Jian Song ; Liang Zhao ; Yongheng Xing ; Caishun Zhang ; Cheng He ; Halime Gul Yaglioglu ; Mustafa Hayvali ; Ayhan Elmali ; Bet眉l K眉莽眉k枚z
• 刊名：Inorganic Chemistry
• 出版年：2015
• 出版时间：August 3, 2015
• 年：2015
• 卷：54
• 期：15
• 页码：7492-7505
• 全文大小：1008K
• ISSN：1520-510X

文摘

Broadband near-IR absorbing trans-bis(trialkylphosphine) Pt(II) bisacetylide binuclear complex (Pt鈥?) was prepared with boron-dipyrromethene (Bodipy) and styrylBodipy acetylide ligands. Pt鈥? shows strong absorption bands at 731 and 503 nm. Singlet energy transfer (EnT) and efficient intersystem crossing of the central coordinated Bodipy ligand were proposed to be responsible for the efficient funneling of the excitation energy to the triplet-state manifold. Reference complexes containing only a single Bodipy ligand were prepared for comparison (with styrylBodipy ligand Pt鈥? or Bodipy ligand Pt鈥?). The molecular structures were confirmed by single-crystal X-ray diffraction. The photophysical properties were studied with steady-state and time-resolved transient absorption spectroscopies, electrochemical characterization, and density functional theory/time-dependent density functional theory calculations. Dual fluorescence was observed for Pt鈥?. Singlet EnT in Pt鈥? was proposed based on the fluorescence quenching/excitation spectra, and femtosecond transient absorption spectra (energy transfer rate constant k_EnT = 2.2 脳 10¹⁰ s^鈥?). With nanosecond transient absorption spectra, intramolecular triplet-state energy transfer in Pt鈥? was proved. Gibbs free energy changes of charge separation indicate that the photoinduced intramolecular electron transfer in Pt鈥? is thermodynamically prohibited. Intermolecular triplet transfer between Pt鈥? and L鈥? was studied with nanosecond transient absorption spectra; the EnT rate and energy transfer efficiency were determined as 3.6 脳 10⁴ s^鈥? and 94.5%, respectively. The singlet oxygen (¹O₂) photosensitizing of Pt鈥? was improved as compared to the complexes containing only a single visible-light-absorbing chromophore.