Steady-state spectroscopy to single out the contact ion pair in excited-state proton transfer
Despite the outstanding relevance of proton transfer reactions, investigations of the solvent dependence on the elementary step are scarce. We present here a probe system of a pyrene-based photoacid and a phosphine oxide, which forms stable hydrogen-bonded complexes in aprotic solvents of a broad po...
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| Main Authors: | , , , , |
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| Format: | Article (Journal) |
| Language: | English |
| Published: |
February 9, 2021
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| In: |
The journal of physical chemistry letters
Year: 2021, Volume: 12, Issue: 6, Pages: 1683-1689 |
| ISSN: | 1948-7185 |
| DOI: | 10.1021/acs.jpclett.0c03593 |
| Online Access: | Verlag, lizenzpflichtig, Volltext: https://doi.org/10.1021/acs.jpclett.0c03593
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| Author Notes: | Alexander Grandjean, J. Luis Pérez Lustres, Stephan Muth, Daniel Maus, and Gregor Jung |
| Summary: | Despite the outstanding relevance of proton transfer reactions, investigations of the solvent dependence on the elementary step are scarce. We present here a probe system of a pyrene-based photoacid and a phosphine oxide, which forms stable hydrogen-bonded complexes in aprotic solvents of a broad polarity range. By using a photoacid, an excited-state proton transfer (ESPT) along the hydrogen bond can be triggered by a photon and observed via fluorescence spectroscopy. Two emission bands could be identified and assigned to the complexed photoacid (CPX) and the hydrogen-bonded ion pair (HBIP) by a solvatochromism analysis based on the Lippert-Mataga model. The latter indicates that the difference in the change of the permanent dipole moment of the two species upon excitation is ∼3 D. This implies a displacement of the acidic hydrogen by ∼65 pm, which is in quantitative agreement with a change of the hydrogen bond configuration from O-H···O to -O···H-O+. |
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| Item Description: | Gesehen am 09.09.2021 |
| Physical Description: | Online Resource |
| ISSN: | 1948-7185 |
| DOI: | 10.1021/acs.jpclett.0c03593 |