Tabletop Femtosecond M-edge X-ray Absorption Near-Edge Structure of FeTPPCl: Metalloporphyrin Photophysics from the Perspective of the Metal
| Autor: | Max Verkamp, Ming-Fu Lin, Kristopher Benke, Michaela Carlson, Josh Vura-Weis, Kaili Zhang, Elizabeth Ryland |
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| Rok vydání: | 2018 |
| Předmět: |
Ligand field theory
Chemistry 02 engineering and technology General Chemistry 010402 general chemistry 021001 nanoscience & nanotechnology Photochemistry 01 natural sciences Biochemistry Porphyrin Catalysis XANES 0104 chemical sciences Photoexcitation chemistry.chemical_compound Colloid and Surface Chemistry Excited state Femtosecond 0210 nano-technology Ground state Spectroscopy |
| Zdroj: | Journal of the American Chemical Society. 140(13) |
| ISSN: | 1520-5126 |
| Popis: | Iron porphyrins are the active sites of many natural and artificial catalysts, and their photoinduced dynamics have been described as either relaxation into a vibrationally hot ground state or as a cascade through metal-centered states. In this work, we directly probe the metal center of iron(III) tetraphenyl porphyrin chloride (FeTPPCl) using femtosecond M2,3-edge X-ray absorption near-edge structure (XANES) spectroscopy. Photoexcitation at 400 nm produces a (π,π*) state that evolves in 70 fs to an iron(II) ligand-to-metal charge transfer (LMCT) state. The LMCT state relaxes to a vibrationally hot ground state in 1.13 ps, without involvement of (d,d) intermediates. The tabletop extreme-ultraviolet probe, combined with semiempirical ligand field multiplet calculations, clearly distinguishes between metal-centered and ligand-centered excited states and resolves competing accounts of Fe(III) porphyrin relaxation. This work introduces tabletop M-edge XANES as a valuable tool for measuring femtosecond dynamic... |
| Databáze: | OpenAIRE |
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