Crown Ether Functionalized Potassium‐Responsive Anionocages for Cascaded Guest Delivery

In many critical biological processes, host–guest chemistry of protein receptors is regulated by effector molecules to realize cascaded delivery of messenger molecules between different targets. Mimicking these natural processes with artificial receptors remains a challenge. Herein, we report a cascaded guest delivery between two anionocages (anion‐coordination‐driven cages), in a reversible manner, wherein binding of K+ ions by a crown ether functionalized, heteroleptic A2L3 (A=anion, L=ligand) anionocage triggers the release and delivery of a TEA+ (tetraethylammonium) guest to another A2L3 anionocage that is a weaker and less K+‐sensitive receptor. Elimination of the K+ with [2,2,2]‐cryptand enables recapture of the TEA+ by the crown ether functionalized anionocage and thus realizes a reversed guest delivery. Moreover, integrative self‐sorting of anionocages is firstly reported, leading to heteroleptic cages with enhanced guest binding affinities. Potassium‐responsive anionocages were developed for cascaded guest delivery in a reversible manner. Binding of K+ by a crown ether functionalized, heteroleptic anionocage triggers the release and delivery of a TEA+ (tetraethylammonium) guest to another anionocage that is a weaker and less K+‐sensitive receptor. This process could be fully reversed by elimination of the K+ with [2,2,2]‐cryptand.