Quantitative and structural investigations of hydrogen bonding interactions in anion binding of mono- and 1,1′-bis-substituted aryl cobaltocenium receptors

Abstract

New acyclic monosubstituted aryl cobaltocenium derivatives, functionalised with- additional hydrogen-bonding amine groups have been prepared. Quantitative investigation of the anion-binding properties by ¹H NMR spectroscopy and electrochemical methods shows enhanced binding believed to be due to amine group participation in hydrogen bonding. Similar recognition studies on 1,1′-bissubstituted aryl cobaltocenium analogues indicate an order of magnitude selectivity for the dihydrogenphosphate anion over simple halide anions. The importance of hydrogen bonding is also illustrated by the first single-crystal structure showing the anion complex of a cobaltocenium receptor.