An Anion Receptor Based on Poly-Substituted Cobalticinium Complexes

Article abstract of DOI:10.1246/bcsj.69.17

Various derivatives of poly-substituted cobalticinium complexes have been synthesized by using substituted cyclopentadienes with a convertible carboxylic group. By 1 H NMR titration experiments, these complexes were shown to behave as a receptor for anions such as Cl^-, Br^-, AcO^-, and p-TsO^-. Planar-chiral anilide derivative 3a showed chiral recognition toward camphor- 10-sulfonate though the difference of the association constants was 10%. The molecular structure including the absolute configuration of 3a have been established by an X-ray crystallographic analysis. The results suggest the hydrophobic cavity constructed by the substituents on the cyclopentadienyl ligands may be an important component for the successful anion complexation.