スピロボラート結合形成を利用した分子認識分子の創製

抄録

The construction of various nanometer-sized cyclophanes has been carried out by the use of reversible formation of spiroborate linkages. Bis(2,3-dihydroxynaphthalene)s were converted into the corresponding cyclic spiroborate trimers in the presence of equimolar amount of boric acid in N,N-dimethylformamide. The cyclic trimer of 2,2’,3,3’-tetrahydroxy-1,1’-binaphthyl possessed a crown-ether-like cavity and exhibited selective recognition toward potassium or barium cations. This cyclic trimer also had bowl-shaped cavities at both sides of its symmetry plane, and acted as a ditopic host that iteratively recognized spherical cationic complex to form a supramolecular polymer structure. Multicomponent construction of cyclic spiroborates was also realized by the combination of oligo(2,3-dihydroxynaphthalene)s and 2,3,6,7-tetrahydroxy-9,10-anthraquinone. It was found that the rectangular-shaped spiroborate nanocycles were constructed in a self-organization manner and exhibited characteristic molecular recognition behavior toward cationic aromatic guests.