ON SUPRAMOLECULAR ARCHITECTURE WATER MOLECULES FORM IN HYDROPHOBIC HYDRATES. Janusz Lipkowski^*, Konstantin Udachin ^#, Jerzy Narbutt ^& and Pawel Staszewski^{* *} Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44, 01 224 Warszawa, Poland, ^# Institute of Inorganic Chemistry, Siberian Branch of Russian Academy of Sciences, Lavrentyeva 3, 630090 Novosibirsk, Russia, ^& Institute of Nuclear Chemistry and Technology, Dorodna 16, 03 195 Warszawa, Poland

In the crystal structures of molecular hydrates different modes of hydration co-exist. These are: hydrophilic hydration, in which water is H-bonded to suitable moieties of the solvated molecule, hydrophobic hydration in which water molecules enclathrate lipophilic parts of molecules or guest moieties, and, ionic interactions if the guest species are solvated in ionized form (like, e.g. alkylammonium fluorides, from which fluoride anions are incorporated into water crystalline framework while the guest-alkylammonium is cationic). It is believed that x-ray studies on crystal structure of water, containing different solute species, may have some importance in understanding possible hydration patterns in solution phases.

In the paper some new x-ray structures of water structures in hydrates will be displayed. These include hydrophobic hydration pattern of Zr(acac)₄ (10H₂0 (as the example of hydrophobic hydration of metal chelates, which is of importance from the point of view of phase equilibria in liquid/liquid extractions), and a series of crown macrocycles and their complexes. In the latter case hydrophilic hydration occurs if the macrocycle is not complexing any guest species. Hydrophobic hydration is strongly dependent both upon geometry of the guest species and the hydrate stoichiometry. The most unexpected architectures found include different layered, channel and zeolite-like structures of water. Most of experimental work required low temperature (Oxford Cryogenics) since the compounds melt below 0( C.