Cationic water host lattice

Attempts to crystallize cation-water host lattices analogous to the per-alkyl ammonium salt hydrates, e.g., tetraalkyl borate hydrates, were unsuccessful [432]. 

In the higher hydrates of the quaternary ammonium salts, the cations are the guest species and the water and anions form the anionic host lattice. In the recently discovered strong add hydrates such as HC104 6H20 [767], the anions are the guests in a cationic water lattice. 

Finally the structure of the tosylate ciyptate of R3Bp demonstrates the size exclusion expected of the large cation (Fig. 11). Even so, it is not devoid of interaction with the cationic host, in the lattice at least, as each anion exhibits one moderately short H-bond contact to one of the NH1 functions of the cryptate. These direct H-bond contacts are often supported by indirect water-mediated links of shorter dimensions, acting as part of branched hydrate chains which run through the less hydrophobic section of the lattice. 

V=9.267(1) nm, Z=4, Ri=0.0S3 and Rw=0,058. The complex is composed of copper cations, nitrate anions, 1,10-phenanthroline, protocatechuic acid and lattice water molecules. The structure of H3PCA, N03 and waters comprises packing of three-dimensional network by hydrogen bonds with cavities. The complex can be considered as a model of host/guest supermolecule. The three-dimensional hydrogen-bonding network is the host species. The Cu(phen)3 cations, guest species, occupy the cavities of the host. 

Few dynamical studies on water in zeolites have been published despite the fact that most of the zeolites are hydrophilic. As a matter of fact the H-bonds between the molecules and the strong interaction with the host couple the external motions to one another, and also to the lattice vibrations. In an earlier paper, Bogomolov et al. followed the dehydration of the NaY zeolite [57] they recorded the inelastic scattering from 0 to 200 meV for the empty zeolite up to the complete loading and compared them to the spectrum of pure water. Up to four molecules per cavity, water is bonded chiefly to the cations through the free electron pair of... 

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