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.