Crown ethers having side arms: a diverse and versatile supramolecular chemistry

Abstract

Abstract Lariat ethers are a variant of crown ethers that have pendant side arms. The original design for these molecules included donor groups in the side arms that were envisioned to enhance alkali metal cation binding without diminishing binding dynamics. Many of the examples that were prepared did fulfill this original vision. The compounds were used as cation binders and carriers. They were found to form membranes, other aggregates, and they were used as model systems to demonstrate alkali metal cation–pi interactions. When alkyl side arms were present, but secondary donors were absent, many of the structures proved to be antimicrobials. Several dialkyl lariat ethers proved to form aggregated pores or ion channels in bilayer membranes. These molecules also proved to be adjuvants that helped to overcome antimicrobial resistance in a range of bacteria and in fungi. The chemical behavior and biological activity are described in this review. Graphical Abstract