Reversible hydrogen-bonded polymerization regulated by allosteric metal templation

Allosteric effects are common in biology, but have not been fully explored in the control of supramolecular polymerization. Herein, ditopic UPy derivatives with acyclic crown ether-like spacers were designed and synthesized, which can undergo supramolecular polymerization through quadruple hydrogen bonding. Upon the addition of K + , drastic molecular conformational change to the U-shape is induced by metal-coordination, reconfiguring remote UPy sites towards the formation of discrete cyclic dimers. Interestingly, the supramolecular polymerization can be restored by simply removing K + by water-extraction. A stable quadruple hydrogen bonded cyclic dimer assisted by metal templation was successfully self-assembled and its reversible transformation to supramolecular polymer was investigated.