Cation-re interactions

The relatively low thermodynamic stability of complexes of hemicarcerands or other container-type hosts is a direct consequence of structural aspects of the walls that make up the inner surface of such compounds. These walls are lined by aromatic subunits while free electron pairs of heteroatoms such as those of the ether oxygen atoms are preferentially oriented to the outside. Complexes are therefore enthalpically stabilized only by weak dispersive interactions. In the case of positively charged guests cation-re interactions can contribute to binding enthalpy as in a self-assembled calixarene-derived capsule [9], but directed interactions such as hydrogen-bonding interactions are usually absent. 

Influence of the water molecule on cation-re interaction Ab initio second order Moller-Plesset perturbation theory (MP2) calculations124... 

Study of Cation-re Interactions vs. Salt Bridges in Aqueous Media Implications for Protein Engineering. 

Contribution of Cation-re Interactions to the Stability of Protein-DNA Complexes. 

Protein-DNA Interfaces Nonadditivity of H-Bond, Stacking, and Cation-re Interactions. 

Gokel, G. W., Barbour, L. J., Ferdani, R., Hu, J. X., Lariat ether receptor systems show experimental evidence for alkali metal cation-pi interactions. Acc. Chem. Res. 2002, 35, 878-886. 

In conclusion, we were able to design AChE inhibitors based on the docking and GRID/GOLPE study which seems to interact simultaneously with the cation-re subsite of the catalytic site and the peripheral site of the enzyme. Eurther support for our docking study came from the crystal structure of a novel Ach E-inhibitor complex [78]. The crystal structure of AChE complexed with the marketed drug donepezil was solved in 1999. Like donepezil, our most potent inhibitors contain a benzylpiperidine moiety which shows a similar position and orientation when compared with the published crystal structure. The comparison of both AchE-inhibitor complexes revealed that both kind of inhibitors adopt a comparable conformation in the narrow binding pocket [12]. As we predicted for our ami-... 

The polarographic behaviour of AgClO has been investigated in anhydrous DMSO, DMF, MeCN, PhCN, PhN02, and other solvents. The half-wave potential was observed to be related to the donicity of the solvents, unless specific cation-solvent interactions occur. A re-investigation of the thermal decomposition of the dioxan complex AgC104,3L has enabled the construction of an enthalpy cycle in which dioxan complexes are favoured only if the lattice energy of the complex exceeds that of the parent AgX salt plus the heat of vaporization of dioxan. ... 

Roelens, S.i Torriti. R. Binding of acetylcholine and quaternary ammonium cations to macrocyclic and acyclic "phane" esters. Evaluation of the cation re-primary interaction through adaptive aromatic hosts. J. Am. Chem. Soc. 1998. 120. 12443-12452. 

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