
We have employed extensive densimetry measurements of guanidinium chloride at UCT Prague, and performed MD simulations at UCT Prague, IOCB Prague, and at Ruđer Bošković Institute, Zagreb. We have collected data on temperature and pressure response of guanidinium chloride hydration, allowing us to determine volumetric properties at infinite dilution, i.e., at single ion limit.
We have clearly demonstrated this response is anomalous, on the half way between ordinary ions (e.g. sodium) and hydrophobic molecules (e.g. benzene). Employing directional analysis and Kirkwood-Buff theory, MD simulations point to hydrophobe-like hydration of quasi-aromatic faces and ion-like hydration of in-plane NH2 moieties. Enjoy the reading of our paper in the ‘Battino and Wilhelm’ Special Issue of the Journal of Chemical Thermodynamics. link