Mitra Almasian, Josipa Grzetic, Johanne van Maurik, Jeffrey D. Steill, Giel Berden, Steen Ingemann, Wybren Jan Buma, and Jos Oomens
The conjugate base of para-coumaric acid, which can be conveniently generated in the gas phase by electrospray ionization (ESI), is a commonly used model system for the chromophore of the photoactive yellow protein. Here we report its gas-phase IR spectrum, which shows that the anion easily adopts a carboxylate structure lying 60 kJ/mol higher in energy than the global minimum phenoxide structure. Generation of the biologically more relevant phenoxide isomer by ESI can be achieved using dry acetonitrile as solvent. © 2012 American Chemical Society.
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Reference: Journal of Physical Chemistry Letters 3 (2012) 2259-2263.
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