Local and Remote Conformational Switching in 2-Fluoro-4-Hydroxy Benzoic Acid

In this work, 2-F-4-OH benzoic acid was isolated in Ar matrices and conformational changes were induced by near-IR irradiating the sample. Upon deposition, three conformers could be observed matrix, denoted as A1, A2, D1, respectively. A1 A2 are trans carboxylic acids, i.e., there is an intramolecular H bond between carbonyl O atoms COOH group, whereas D1 a cis with F atom which otherwise has same structure A1. The difference orientation of regard to atom, whether they on opposite or side molecule, All have their 4-OH facing direction atom. stretching overtones OH groups selectively excited case each conformer. Unlike did not show any response irradiation, converted higher energy form D1. conformer spontaneously converts back via tunneling; however, conversion rate significantly increased exciting vibrational Quantum efficiencies been determined for ‘local’ ‘remote’ excitations, when group order induce rotamerization group. Both switching type vibration, allows direct comparison how much lost dissipation during two processes. experimental findings indicate that excitation only marginally more efficient than one.