Dual-Responsive [2]Pseudorotaxane On the basis of a pH-Sensitive Pillar[5]arene and Its Application in the Fabrication of Metallosupramolecular Polypseudorotaxane

Metallosupramolecular polymer, an appealing polymeric material, plays important roles in many fields including catalysis, electrochemical devices, conducting materials and so on. As a class of metallosupramolecular polymers, metallosupramolecular polypseudorotaxane has attracted great attention not only because of its wide applications but also due to its facile synthesis which is by metal coordination between metal and macrocycle-based pseudorotaxane. The introducing of stimuli-responsive property into the metallosupramolecular polypseudorotaxane system will enrich their functionality. Herein, a triple stimuli-responsive metallosupramolecular polypseudorotaxane constructed by pillararene-based host–guest interaction and copper coordination. First, a new pH-sensitive pillar[5]­arene host (H) was synthesized. An azastilbenzene derivative, trans- 4,4′-vinylenedipyridine (trans-G) was chosen as the guest molecule to construct a [2]­pseudorotaxane based on H and trans-G. The [2]­pseudorotaxane displayed pH- and photo- dual stimuli-responsiveness. Then the [2]­pseudorotaxane was used to construct a pH-, photo- and cyanide-triple stimuli-responsive metallosupramolecular polypseudorotaxane based on Cu­(II) ion coordination.