Anion Receptors Containing Heterocyclic Rings

Heterocyclic groups can play key roles as hydrogen bond donors and charged components in a wide range of anion receptors. This chapter reviews the roles the heterocycles play in anion recognition, covering pyrrole-based systems (both macrocyclic and acyclic, including synthetic systems and natural products such as prodigiosin), indole-based receptors, and foldamers- and charged-imidazolium-based hosts. The chemistry of pyridine- and quinoline-based receptors, including metal-templated systems that employ transition metals to assemble simple organic components, and the role of bipyridinium in anion complexation and sensing are also reviewed. Finally, the chemistry of 1,2,3-triazoles as components of hosts that use CH· · ·anion hydrogen bonds to complex anionic guests is examined.