Supramolecular Polymerization with Dynamic Self-Sorting Sequence Control

Synthetic polymerization and supramolecular polymerization with sequence control are far from an easy task. Herein, a narcissistic self-sorting supramolecular polymer is prepared with a sequence of (-AA-BB-)(n) by using cucurbit[8]uril (CB[8])-based ternary complexes as supramolecular monomers, which are spontaneously formed from heteroditopic AB-type guest and CB[8]. Supramolecular polymerization and the structural changes at each stage of polymerization have been successfully demonstrated by NMR, UV-vis, and fluorescence spectra. The self-sorting starts from the second step of polymerization after the formation of different ternary complexes as supra-monomers. The dynamic supramolecular interactions and the thermodynamic stability of the host-guest complexes are found to be the crucial factors to drive the sequence control of the supramolecular polymers. Furthermore, the water-soluble supramolecular polymer is red-emissive and can serve as a fluorescent sensor to detect morphine in artificial urine with considerable stability, sensitivity, and accuracy. And it can also distinguish heroin and morphine, two kinds of opioids with similar structures.