Pillar[n]MaxQ: A New High Affinity Host Family for Sequestration in Water

We report the synthesis, X‐ray crystal structure, and molecular recognition properties of pillarn]arene derivative P6]AS , which we refer to as Pillar6]MaxQ along with analogues P5]AS and P7]AS toward guests 1 – 18 . The ultratight binding affinity of P5]AS and P6]AS toward quaternary (di)ammonium ions renders them prime candidates for in vitro and in vivo non‐covalent bioconjugation, for imaging and delivery applications, and as in vivo sequestration agents.