Coordination Chemistry and Applications of Phenolic Homooxa- and Homoazacalixarene-Metal Complexes

Heteracalixarenes are members of the calixarene family in which heteroatoms such as oxygen, nitrogen, sulfur, selenium, or silicon are inserted between the methylene bridges or replace them entirely. The incorporation of heteroatoms affects the metal binding affinities of these calixarenes over their all-carbon analogues, through the abilities of the heteroatoms both to bind directly and to influence lower rim phenolic binding. This chapter covers the literature concerning phenolic homooxa- and homoazacalixarene-metal complexes mainly for the last two decades (1994–2014). The syntheses of homooxa- and homoazacalixarenes containing free OH groups at the lower rim are described and their coordination chemistry towards alkali, alkaline earth, transition, heavy, lanthanide and actinide metals is discussed. Examples of crystal structures of these metal complexes are given, as well as brief descriptions of their applications in fields such as catalysis, and metal cation extraction and transport. Keywords: alkali and alkaline earth metals; coordination chemistry; homoazacalixarenes; homooxacalixarenes; lanthanide and actinide metals; metal phenolates; metal complexes; transition and heavy metals