Synthesis of Intelligent Molecule and Structural Study for its Molecular Complexes

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Chemistry of molecular recognition is the chemistry of intermolecular bond. Since recognition at the molecular level is a fundamental characteristic of biological systems, extensive investigations have been focused on this field. Intermolecular bonds are consist of various interaction, hydrophobic, charge transfer, electrostatic, pi-pi stacking, hydrogen bonding, ion-dipolar interaction and so on. In order to know the main contributing interaction in a molecular complex, it should be clarified the precise structure of the complex in solution. We developed an efficient method for structural analysis of an extremely flexible macrocyclic compound, which utilizes both the molecular mechanics calculation and effect of magnetic anisotropy of aromatic ring current. We have shown that the method can be applicable for the structural elucidation of intermolecular complex in solution. Conformational control for flexible macrocycle is one of the most challenging problems. We attained the control of [m.m]orthocyclophanes having two crown units by complexation of cationic species. Synthetic approach of an allosteric host using this[m.m]orthocyclophanes having two crown units as basic skeleton was carried out. The synthesis of aza-crown ether linked with monodeoxycalix[4]arene was carried out. The compound has potent ability for selective transport of Na cation through organic liquid phase. Calix[5]arene has wider hydrophobic cavity than the smaller congener. We applied this wide cavity for construction of a host molecule by the linkage of dipolar functional groups at its upper rim. Synthesis of the guest molecule having two benzoic acid moieties has carried out. It bound two imidazole molecules in solution. Molecular mechanics calculation using AMBER force field implemented in MacroModel has disclosed that one imidazolium ion is encapsulated in the hydrophobic cavity with an aid of cation-pi interaction to calizarene pi-wall. The second imidazolium ion was bound by the two carbo