Photophysics of First-Generation Photomolecular Motors
| Autor: | Wojciech Danowski, Palas Roy, Stephen R. Meech, Andy S. Sardjan, Wesley R. Browne, Ben L. Feringa |
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| Přispěvatelé: | Molecular Inorganic Chemistry, Synthetic Organic Chemistry, Basic and Translational Research and Imaging Methodology Development in Groningen (BRIDGE) |
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Steric effects
010304 chemical physics Polarity (physics) Chemistry Quantum yield 010402 general chemistry 01 natural sciences Molecular machine 0104 chemical sciences Reaction coordinate Chemical physics Yield (chemistry) 0103 physical sciences Polar Physical and Theoretical Chemistry Physics::Chemical Physics Isomerization |
| Zdroj: | The Journal of Physical Chemistry. A: Molecules, Spectroscopy, Kinetics, Environment, & General Theory, 125(8), 1711-1719. AMER CHEMICAL SOC |
| ISSN: | 1089-5639 |
| Popis: | Light-driven unidirectional molecular rotary motors have the potential to power molecular machines. Consequently, optimizing their speed and efficiency is an important objective. Here, we investigate factors controlling the photochemical yield of the prototypical unidirectional rotary motor, a sterically overcrowded alkene, through detailed investigation of its excited-state dynamics. An isoviscosity analysis of the ultrafast fluorescence decay data resolves friction from barrier effects and reveals a 3.4 ± 0.5 kJ mol-1 barrier to excited-state decay in nonpolar media. Extension of this analysis to polar solvents shows that this barrier height is a strong function of medium polarity and that the decay pathway becomes near barrierless in more polar media. Thus, the properties of the medium can be used as a route for controlling the motor's excited-state dynamics. The connection between these dynamics and the quantum yield of photochemical isomerization is probed. The photochemical quantum yield is shown to be a much weaker function of solvent polarity, and the most efficient excited-state decay pathway does not lead to a strongly enhanced quantum yield for isomerization. These results are discussed in terms of the solvent dependence of the complex multidimensional excited-state reaction coordinate. |
| Databáze: | OpenAIRE |
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