Synthesis of Bis-naphthalene and Their Derivatives and Their Complexation with Organic Cation

In this research, the structure of the bis-naphthalene molecular resulting from 2-naphthol and 1,1,1',1'-tetramethoxypropane was modified, and six derivatives with different substituents, sidewalls or bridges were synthesized. Their structures were studied by X-ray crystallography and molecular modelling, and all possess curved architectures. Electrostatic potential energy surfaces show that their inner cavities are electron-rich, and may complex with organic cations through cation-pi interactions. Their binding stoichiometry and association constants with the 1,4-diazabicyclo[2.2.2] octane (DABCO)-based organic cation were studied by H-1 NMR titration and Job's plot. The results show that electron-rich molecules have much stronger association, and reducing the carbon atom in the bridge significantly decreases their association ability. These novel curved structures may work as building blocks for the construction of new macrocyclic receptors.