IR-UV spectroscopy of jet-cooled 1-indanol: Restriction of the conformational space by hydration

The effect of hydration on a flexible amphiphilic molecule has been studied on the example of 1-hydroxyindan (1-indanol). Studies in jet-cooled conditions by means of resonance-enhanced two-photon ionization and IR-UV double resonance experiments show that the mono-hydrate 1-indanol(H2O) is formed in a dominant isomer, as well as the di-hydrate 1-indanol(H2O)(2). 1-Indanol(H2O) favors a cooperative hydrogen bond pattern with -OH center dot center dot center dot O(H)-H center dot center dot center dot pi it topology, while 1-indanol(H2O)(2) forms a cyclic hydrogen bond network with three OH center dot center dot center dot O interactions. The single conformation observed for the hydrates contrasts with the bare molecule which shows two dominant conformations, with the hydroxyl in axial or in equatorial position, respectively. Hydration therefore results in a restriction of the conformational space and conformational locking. (C) 2014 Elsevier B.V. All rights reserved.