Squaramido-Based Receptors : Applicability of Molecular Interaction Potential to Molecular Recognition of Polyalkylammonium Compounds

Abstract

[eng] A computational study of the mechanism of host±guest complexation between quaternary ammo- nium compounds and squaramido-based tripodal recep- tors has been carried out. Semiempirical molecular orbital calculations, which are in qualitative agreement with experimental results have been performed using the PM3 Hamiltonian. Molecular interaction potential (MIP) maps were used to analyze the suitability of both host and guest binding units for a high-a nity recogni- tion process. MIP calculations were computed from PM3 wavefunctions of the corresponding ammonium cations and dimethyl squaramide as a model compound for the hydrogen-bond-acceptor unit of the receptors. MIP analyses are helpful for understanding the host± guest process from the point of view of the double- complementarity principle.