Electrochemical measurement of switchable hydrogen bonding in an anthraquinone-based anion receptor

The electrochemistry of a novel anion receptor is presented. The receptor 1,3-diphenylcarboxamidoanthraquinone (AAR) in the absence of an appropriate anion behaves as an anthraquinone system in the presence of a strong hydrogen bond donor. In this case, the electrochemical evidence supports the suggestion that the hydrogen bonding with the anthraquinone occurs at least partially through intra- or intermolecular interactions. It is suggested that these interactions stabilise both the semiquinone and dianion species resulting from reduction of AAR. However, in the presence of a suitable competitive anion (specifically F−), the hydrogen-bond donor groups bind to the anion rather than the quinone oxygen atoms. This removes the hydrogen bonding interaction to the redox-active quinone centre and hence alters the electrochemistry significantly. In the presence of F−, two one-electron quasireversible electrochemical processes are observed.