could act as the cores for the further construction of supramolecular polymer
network after the addition of homoditopic guest molecules to form the host-guest
complexation with pillar[5]arene. More importantly, by taking the advantages of
the dynamic nature of metal-ligand bonds and host-guest interactions, reversible
multiple stimuli-responsive gel-sol phase transition of such polymer gels was successfully realized, which could be destroyed by addition of TBABr and competitive
guests and recovered by adding AgOTf to remove Br- and pillar[5]arene to remove
competitive guests.
Wang and coworkers adopted “threading followed by coordination” method to
synthesize coordination polymer [20]. Firstly, the guest molecule with the pyridine
unit as the ending group was synthesized, which could form a stable 1:1 complexation with pillar[5]arene. Due to the introduction of pyridine motif, the complex
could further coordinate with metal cation to form the supramolecular polymer.
Therefore, the Pd(OAc) 2 was added to form the linear polymer for the 1:1 binding
ratio between the pyridine guest and Pd(OAc) 2 . Interestingly, due to the partial
encapsulation of guest molecules by pillar[5]arene, the intramolecular hydrogen
bonding would exist between the formed polyrotaxane backbones, leading to the
further cross-linking to form the supramolecular gel.
Moreover, Shi and coworkers reported an orthogonal supramolecular polymer, in
which the host-guest interaction, πÁÁÁπ stacking, and metal-ligand binding were
introduced into this system (Fig. 9) [21]. Firstly, the terpyridine derivative with
a long bromoalkyl chain was synthesized, which could form the 1:1 inclusion
complex with pillar[5]arene by the recognition motif of bromoalkyl chain, as well
as the 2:1 coordination compound with the Eu(III) ion by the terpyridine motif.
Fig. 9 The cartoon representation of the formation of a linear supramolecular polymer reported by
Shi and coworkers. (Reprinted with permission from Ref. [21]. Copyright © 2017, Royal Society of
Chemistry)
13 Pillararene-Based Supramolecular Polymer
351
network after the addition of homoditopic guest molecules to form the host-guest
complexation with pillar[5]arene. More importantly, by taking the advantages of
the dynamic nature of metal-ligand bonds and host-guest interactions, reversible
multiple stimuli-responsive gel-sol phase transition of such polymer gels was successfully realized, which could be destroyed by addition of TBABr and competitive
guests and recovered by adding AgOTf to remove Br- and pillar[5]arene to remove
competitive guests.
Wang and coworkers adopted “threading followed by coordination” method to
synthesize coordination polymer [20]. Firstly, the guest molecule with the pyridine
unit as the ending group was synthesized, which could form a stable 1:1 complexation with pillar[5]arene. Due to the introduction of pyridine motif, the complex
could further coordinate with metal cation to form the supramolecular polymer.
Therefore, the Pd(OAc) 2 was added to form the linear polymer for the 1:1 binding
ratio between the pyridine guest and Pd(OAc) 2 . Interestingly, due to the partial
encapsulation of guest molecules by pillar[5]arene, the intramolecular hydrogen
bonding would exist between the formed polyrotaxane backbones, leading to the
further cross-linking to form the supramolecular gel.
Moreover, Shi and coworkers reported an orthogonal supramolecular polymer, in
which the host-guest interaction, πÁÁÁπ stacking, and metal-ligand binding were
introduced into this system (Fig. 9) [21]. Firstly, the terpyridine derivative with
a long bromoalkyl chain was synthesized, which could form the 1:1 inclusion
complex with pillar[5]arene by the recognition motif of bromoalkyl chain, as well
as the 2:1 coordination compound with the Eu(III) ion by the terpyridine motif.
Fig. 9 The cartoon representation of the formation of a linear supramolecular polymer reported by
Shi and coworkers. (Reprinted with permission from Ref. [21]. Copyright © 2017, Royal Society of
Chemistry)
13 Pillararene-Based Supramolecular Polymer
351