Chemoresponsive Supramolecular Polypseudorotaxanes with Infinite Switching Capability

Article abstract of DOI:10.1002/anie.202107903

Chemoresponsive supramolecular systems with infinite switching capability are important for applications in recycled materials and intelligent devices. To attain this objective, here a chemoresponsive polypseudorotaxane is reported on the basis of a bis(p

Full text of DOI:10.1002/anie.202107903

Angewandte
Research Articles
Chemie
How to cite:
International Edition: doi.org/10.1002/anie.202107903
German Edition: doi.org/10.1002/ange.202107903
Supramolecular Chemistry
Chemoresponsive Supramolecular Polypseudorotaxanes with Infinite
Switching Capability
Yitao Wu, Liqing Shangguan, Qi Li, Jiajun Cao, Yang Liu, Zeju Wang, Huangtianzhi Zhu,*
Feng Wang,* and Feihe Huang*
Abstract: Chemoresponsive supramolecular systems with
infinite switching capability are important for applications in
recycled materials and intelligent devices. To attain this
objective, here a chemoresponsive polypseudorotaxane is
reported on the basis of a bis(p-phenylene)-34-crown-10
macrocycle (H) and a cyano-substituted viologen guest (G).
H and G form a [2]pseudorotaxane (HꢀG) both in solution
and in the solid state. Upon addition of AgSF6, a polypseudor-
otaxane (denoted as [H·G·Ag]n) forms as synergistically
driven by host–guest complexation and metal-coordination
interactions. [H·G·Ag]n depolymerizes into a [3]pseudorotax-
ane (denoted as H2·G·Ag2·acetone2) upon addition of H and
AgSF6, while it reforms with successive addition of G. The
transformations between [H·G·Ag]n and H2·G·Ag2·acetone2
can be switched for infinite cycles, superior to the conventional
chemoresponsive supramolecular polymeric systems with
limited switching capability.
artificial chemoresponsive systems.[2] Supramolecular poly-
mers, as pioneered by Lehn and Meijer, denote the polymeric
arrays of monomer units held together by reversible non-
covalent interactions.[3] When chemical triggers weaken or
destroy the noncovalent bonds in supramolecular polymers,
stimuli-responsiveness can be amplified from the molecular to
the macroscopic level, which is intriguing for the fabrication
of adaptive materials.[4] Despite the progress achieved in this
field, the invasive character of chemical triggers produces
wastes and thereby changes the original environment, ham-
pering structural reformation of supramolecular polymers.[5]
Therefore, for state-of-art chemoresponsive supramolecular
polymers, their reversibility can be operated for limited
cycles, detrimental for the applications in recycled materials
and intelligent devices.[6] It remains challenging to develop
supramolecular polymers with infinite chemo-switching ca-
pability.
Since the accidental discovery of dibenzo[18]crown-6 by
Pedersen in 1967,[7] synthetic macrocycles such as crown
ethers, cyclodextrins, calixarenes, pillararenes, and cucurbi-
turils have attracted tremendous attention due to their highly
specific and selective complexation toward the complemen-
tary guests.[8–12] Macrocycle-directed supramolecular poly-
merization was achieved by Gibson,[13] Harada,[14] and our
group,[15] by employing macrocyclic receptor/guest recogni-
tion as the non-covalent connecting units. Additionally,
Zhangꢀs and Stoddartꢀs groups threaded the macrocycles
onto the linker units.[16,17] It rigidified supramolecular mono-
mers, facilitating linear supramolecular polymerization rather
than cyclic oligomerization. We envisage that the elaborate
combination of the above two roles of macrocycles will be
able to pave the way for chemo-reversible supramolecular
polymerization/depolymerization with infinite switching ca-
pability. On one hand, the presence of excess macrocycles
gives rise to supramolecular depolymerization via the “chain-
stopping” effect. On the other hand, these macrocycles can
move back to the linking point of supramolecular monomers,
leading to supramolecular repolymerization under the spe-
cific chemical triggering conditions. By taking advantage of
the adaptive macrocycle/guest complexation character, we
can solve the irreversible issues encountered in traditional
chemoresponsive supramolecular polymeric systems.
Introduction
Chemical triggers are important to modify the structures
and functions of biological systems, as illustrated by the
denaturation and renaturation processes encountered in lipid
bilayers, proteins, and DNA.[1] Inspired by these fascinating
behaviors, chemists have devoted great efforts to construct
[*] Y. Wu, Dr. L. Shangguan, Q. Li, J. Cao, Y. Liu, Z. Wang, H. Zhu,
Prof. Dr. F. Huang
State Key Laboratory of Chemical Engineering
Key Laboratory of Excited-State Materials of Zhejiang Province
Stoddart Institute of Molecular Science, Department of Chemistry
Zhejiang University, Hangzhou 310027 (P. R. China)
E-mail: htzzhu@zju.edu.cn
fhuang@zju.edu.cn
Prof. Dr. F. Wang
CAS Key Laboratory of Soft Matter Chemistry
Department of Polymer Science and Engineering
University of Science and Technology of China
Hefei 230026 (P. R. China)
E-mail: drfwang@ustc.edu.cn
Prof. Dr. F. Huang
ZJU-Hangzhou Global Scientific and
Technological Innovation Center
Hangzhou 311215 (P. R. China)
and
Green Catalysis Center and College of Chemistry
Zhengzhou University, Zhengzhou 450001 (P. R. China)
To attain this objective, herein a novel supramolecular
polymer (denoted as [H·G·Ag]n, Scheme 1), namely a poly-
pseudorotaxane, has been developed. At first, a [2]pseudor-
otaxane (HꢀG) was fabricated from a bis(p-phenylene)-34-
crown-10 (H) macrocycle and a paraquat guest (G) with the
presence of two cyano groups. It self-assembled into
Supporting information and the ORCID identification number(s) for
the author(s) of this article can be found under:
https://doi.org/10.1002/anie.202107903.
&&&&
ꢀ 2021 Wiley-VCH GmbH
Angew. Chem. Int. Ed. 2021, 60, 2 – 8
These are not the final page numbers!

Angewandte
Research Articles
Chemie
shifts. The 2D nuclear Overhauser effect spectroscopy
(NOESY) spectrum of HꢀG showed nuclear Overhauser
effect (NOE) signals between Ha-d of H and H1-4 of G, proving
the host–guest complexation between H and G (Figure S6).
The binding thermodynamics of HꢀG were acquired via
1H NMR titration experiments (298 K, [D6]acetone). Accord-
ing to a molar ratio plot (Figure S9), the complexation
stoichiometry was 1:1 (Figure S10). The association constant
(Ka) of HꢀG was determined to be (6.10 Æ 0.24) ꢁ 102 MÀ1 by
employing a nonlinear curve-fitting method (Figure S11).[18]
Yellow single crystals of HꢀG were obtained by slowly
evaporating an acetone solution of equimolar H and G. The
host–guest complex crystal structure (Figure 2) was analyzed
via single crystal X-ray crystallography. As shown in Figure 2,
HꢀG with a 1:1 complexation stoichiometry was observed in
Scheme 1. Chemical structures and representations of H, G, Ag+ and
acetone, and representations of the formation of [2]pseudorotaxane
HꢀG from H and G, together with the reversal transformations
between polypseudorotaxane [H·G·Ag]n and [3]pseudorotaxane
H2·G·Ag2·acetone2.
À
the solid state. The complexation was driven by C H···O
interactions between the hydrogen atoms on G and the
oxygen atoms on H with the distances of 2.585 ꢂ (Figures 2
and S3). The phenylene rings of H were p-stacked with both
pyridinium rings of G with the centroid-centroid distances of
3.372 and 4.332 ꢂ (Figures 2 and S3). The dihedral angles
between phenylene rings and pyridinium rings were deter-
mined to be 7.618 (Figures 2 and S3). Accordingly, HꢀG
[H·G·Ag]n upon metal–ligand coordination between the
cyano groups and Ag+ cation. Upon adding an excess of H
and Ag+ cation in acetone, [H·G·Ag]n depolymerizes to
a [3]pseudorotaxane (denoted as H2·G·Ag2·acetone2) through
adaptive host–guest reorganization. The successive addition
of G removed the “chain-stopping” effect of H, giving rise to
the revival of [H·G·Ag]n. Thanks to the absence of waste
formation, the depolymerization/repolymerization processes
switched reversibly and adaptively for infinite cycles, which is
promising for applications in functional materials with
degradable and self-healing properties.
Results and Discussion
First, host–guest recognition between H and G was
established and characterized. As shown in Figure 1, after
mixing equimolar H and G in [D6]acetone, the proton nuclear
magnetic resonance (1H NMR) signals relating to protons H1,2
of pyridinium rings of G exhibited upfield shifts, while
protons H3,4 of phenyl rings of G shifted downfield. Mean-
while, the peaks relating to protons Ha-d on H revealed upfield
Figure 2. The single-crystal structure of HꢀG: a) top view; b) side
À
view. C gray, O red, N blue. PF6 ions, acetone molecules, and H
atoms except the ones involved in hydrogen bonding interactions
between H and G were omitted for clarity. Hydrogen-bond parameters:
À
H···O distances [ꢁ], C···O distances [ꢁ] and C H···O angles [deg] of
À
C H···O hydrogen bonds: a, 2.585, 3.428, 148.06; b, 2.585, 3.428,
148.06. Face-to-face p-stacking parameters: centroid–centroid distan-
ces [ꢁ], 3.732, 3.732, 4.332, 4.332; ring plane/ring plane inclinations
[deg], 7.61, 7.61, 7.61, 7.61. The centroid–centroid distance [ꢁ] and
dihedral angle [deg] between the two pyridium rings of G: 4.288 and
0.[20]
Figure 1. Partial 1H NMR spectra (600 MHz, [D6]acetone, 298 K):
a) 10.0 mM H; b) 10.0 mM H and G; c) 10.0 mM G.
Angew. Chem. Int. Ed. 2021, 60, 2 – 8
ꢀ 2021 Wiley-VCH GmbH
www.angewandte.org
&&&&
These are not the final page numbers!

Angewandte
Research Articles
Chemie
displayed a typical [2]pseudorotaxane structure. The cyano
groups were located outside of the cavity, rendering it suitable
for metal-coordination.
We then sought to fabricate a linear supramolecular
polymer, whose formation was driven by metal-coordination
interactions with the HꢀG recognition motif. As the first step,
one equivalent AgSbF6 was added to G. As shown in
Figure 3a and b, the protons related to G became narrow,
Figure 4. Monomer concentration dependence of diffusion coefficient
D (500 MHz, [D6]acetone, 298 K) of [H·G·Ag]n.
that as the H, G and AgSbF6 concentrations increased, the
diffusion coefficient D gradually decreased (Figure 4). This
result indicated the concentration dependence of the supra-
molecular polymerization process, giving rise to high molec-
ular weight polypseudorotaxanes at high concentration.
Intriguingly, single crystals of [H·G·Ag]n were obtained by
slowly evaporating an acetone solution of equimolar H, G and
AgSbF6. As shown in Figure 5a, the crystal structure ex-
hibited an ordered three-component polypseudorotaxane
structure, as synergistically driven by metal-coordination
and host–guest interactions (Figures 5a and S4). In the
[H·G·Ag]n structure, coordination between the cyano groups
and Ag atoms formed a linear polymeric structure. The
distances of Ag···N coordination bonds were found to be 2.203
and 2.268 ꢂ, with a N···Ag···N angle of 135.438 (Figure 5a).
Notably, the Ag+ cation was also stabilized by three O-Ag
interactions rendered by H. Host–guest complexation also
existed in the crystal structure, in which H was evenly
distributed and threaded by the polymer chain. It exhibited
Figure 3. Partial 1H NMR spectra (600 MHz, [D6]acetone, 298 K):
a) 10.0 mM G; b) 10.0 mM G and AgSbF6; c) 10.0 mM H and G;
d) 10.0 mM H, G and AgSbF6.
because of metal-coordination interactions between Ag+ and
the cyano groups. With reference to the previous reports, it
indicated Ag+ coordination of G into an infinite polymeric
chain.[19] After validating the fabrication of the linear polymer
in the control system, we applied the same procedure in the
HꢀG system toward the fabrication of a polypseudorotaxane.
With the addition of one equivalent AgSbF6 to a solution of
HꢀG, protons Ha-d on H revealed downfield shifts due to the
decreased electron densities. Protons H1,2 on G revealed
downfield shifts and H3,4 revealed no significant shifts (Fig-
ure 3c and d). These results indicated metal-ligand coordina-
tion interactions between G and Ag+ with no interference
from H.
À
C H···O interactions between the hydrogen atoms on G and
Diffusion ordered NMR spectroscopy (DOSY) experi-
ments ([D6]acetone, 298 K) were carried out to prove the
formation of a supramolecular polypseudorotaxane at high
monomer concentration (Figures S14–S16). Upon addition of
equimolar G to a solution of H (10.0 mM), the signals related
to H and G almost appeared at the same horizontal line in the
DOSY spectrum. This suggested the formation of HꢀG, with
a measured diffusion coefficient value of 8.91 ꢁ 10À10 m2 sÀ1
(Figure S14). [H·G·Ag]n was then prepared by adding one
equivalent AgSbF6 to a solution of HꢀG (10.0 mM). After
addition of AgSbF6, the signals relating to HꢀG were still
located at the same horizontal line in the DOSY spectrum,
the oxygen atoms on H, with distances of 2.225 and 2.639 ꢂ
(Figures 5a and S4). Different from HꢀG, in the structure of
[H·G·Ag]n, the phenylene rings of H were p-stacked with
a phenylene ring of G, with a centroid-centroid distance of
4.007 ꢂ (Figure S4). The dihedral angle between the phenyl-
ene ring of H and the phenylene ring of G was determined to
be 6.988 (Figure S4). The enhanced donor-acceptor interac-
tions in [H·G·Ag]n gave rise to red-colored single crystals, in
contrast to the yellow-colored single crystals in case of HꢀG.
The chemoresponsiveness of [H·G·Ag]n was then studied.
Considering that H provides three cation-oxygen non-cova-
lent bonds toward Ag+ in [H·G·Ag]n (Figure 5a), we inves-
tigated whether or not H could serve as a competitive ligand
instead of the cyano units. It behaved like a chain-stopper
unit, leading to the breakup of the [H·G·Ag]n structure.
Interestingly, H2·G·Ag2·acetone2 single crystals were obtained
upon adding an excess of H and AgSbF6 to [H·G·Ag]n. The
but with
a decreased diffusion coefficient of 3.89 ꢁ
10À10 m2 sÀ1. This suggested that the Ag+ coordination didnꢀt
destroy HꢀG, while it orthogonally coordinated with the
cyano groups to form [H·G·Ag]n (Figure S16). Furthermore,
the concentration-dependent DOSY experiments revealed
&&&&
www.angewandte.org
ꢀ 2021 Wiley-VCH GmbH
Angew. Chem. Int. Ed. 2021, 60, 2 – 8
These are not the final page numbers!

Angewandte
Research Articles
Chemie
addition of H and AgSbF6 as the chain stoppers. DOSY
experiments were used to monitor the change of diffusion
coefficient D. As shown in Figure 6a, upon addition of one
more equivalent H and AgSbF6, the diffusion coefficient of
the solution increased, proving the disassembly of [H·G·Ag]n
to form H2·G·Ag2·acetone2. The polymerization of
H2·G·Ag2·acetone2 was reactivated by adding one equivalent
of G. The diffusion coefficient was decreased along with the
addition. The diffusion coefficients of [H·G·Ag]n and
H2·G·Ag2·acetone2 were transformed for multiple cycles
(Figure 6b). This phenomenon indicated full reversibility
between [H·G·Ag]n and H2·G·Ag2·acetone2 with infinite
switching capability.
The morphology of [H·G·Ag]n was investigated by trans-
mission electron microscopy (TEM) and scanning electron
microscopy (SEM). Free H and G were observed to assemble
into random aggregates without a regular morphology, while
H2·G·Ag2·acetone2 self-assembled into spherical structures
(Figures S17–S22). By contrast, adding one equivalent of
AgSbF6 to a solution of G or HꢀG led to the appearance of
rod-like fibers, suggesting the formation of linear supra-
Figure 5. Single crystal structures: a) [H·G·Ag]n. N···Ag···N bonds pa-
rameters: c=2.268 ꢁ; d=2.203 ꢁ; q=135.438. b) H2·G·Ag2·acetone2.
À
C gray, O red, N light blue, Ag dark blue. PF6 ions, SbF6À ions, and H
atoms except the ones involved in hydrogen bonding interactions
between H and G were omitted for clarity. Hydrogen-bond parameters:
À
H···O distances [ꢁ], C···O distances [ꢁ] and C H···O angles [deg] of
À
C H···O hydrogen bonds, e, 2.225, 3.083, 151.290; f, 2.639, 3.078,
108.172. Face-to-face p-stacking parameters: centroid-centroid distan-
ces [ꢁ], [H·G·Ag]n, 4.007; H2·G·Ag2·acetone2, 3.371, 3.853, 4.071; ring
plane/ring plane inclinations (deg), [H·G·Ag]n, 6.98; H2·G·Ag2·acetone2,
8.43, 14.55, 2.11. The centroid–centroid distance [ꢁ] and dihedral angle
(deg) between the pyridium rings of G: [H·G·Ag]n, 4.260 and 14.15;
H2·G·Ag2·acetone2, 4.270 and 6.07.[20]
H:G stoichiometry in H2·G·Ag2·acetone2 was 2:1 (Figure 5b).
Each Ag+ cation was coordinated to three oxygen atoms on
H, one cyano group and one acetone molecule. In the crystal
structure, the phenylene rings of H were p-stacked with the
phenylene rings of G, with centroid-centroid distances of
3.371–4.071 ꢂ and dihedral angles between phenylene rings
of H and phenylene rings of G of 2.11–14.558 (Figure S5).
Hence, upon adding an excess of H and AgSbF6, [H·G·Ag]n
was destroyed and transformed to H2·G·Ag2·acetone2.
According to 2D NOESY spectra, correlation signals
existed between Ha-d of H and H1-4 of G in [H·G·Ag]n. The
results were similar to those of HꢀG, yet different from those
of H2·G·Ag2·acetone2. The phenomena indicated that the
host–guest complexation mode between H and G was the
same in [H·G·Ag]n and HꢀG. In comparison,
H2·G·Ag2·acetone2 altered the H/G complexation structure
(Figures S7 and S8). These experimental results matched well
with the single-crystal structures of HꢀG, [H·G·Ag]n and
H2·G·Ag2·acetone2 (Figures 2 and 5).
Figure 6. Diffusion coefficients D (500 MHz, [D6]acetone, 298 K) of
a) [H·G·Ag]n (10.0 mM) upon adding extra H + AgSbF6 (from 0 to
1.0 equiv.) and G (from 0 to 1.0 equiv.) gradually and b) multiple
switchings between [H·G·Ag]n and H2·G·Ag2·acetone2.
The transformation from [H·G·Ag]n to H2·G·Ag2·acetone2
was also performed in solution. A 10.0 mM [H·G·Ag]n
solution was prepared at first, followed by the gradual
Angew. Chem. Int. Ed. 2021, 60, 2 – 8
ꢀ 2021 Wiley-VCH GmbH
www.angewandte.org
&&&&
These are not the final page numbers!

Angewandte
Research Articles
Chemie
molecular polymers via metal-coordination (Figure 7). The
morphological conversions between linear structures (derived
from [H·G·Ag]n) and spherical structures (derived from
H2·G·Ag2·acetone2) were observed for five cycles without
waste production (Figure S23).
Figure 8. Diffusion coefficients D (500 MHz, [D6]acetone, 298 K) of
[H·G·Ag]n (10.0 mM) upon adding one equivalent TBAI and then
adding one equivalent AgSbF6.
it suitable for metal-coordination. [H·G·Ag]n was prepared by
adding one equivalent AgSbF6 to a solution of HꢀG.
Figure 7. TEM images: a) [G·Ag]n; b) [H·G·Ag]n. SEM images:
c) [G·Ag]n; d) [H·G·Ag]n. Samples were prepared from highly concen-
trated solutions.
[H·G·Ag]n was dissociated to
a
[3]pseudorotaxane
H2·G·Ag2·acetone2 upon addition of one more equivalent H
and AgSbF6, and converted back to the initial state after the
successive addition of G. The crystal structures and binding
modes of [H·G·Ag]n and H2·G·Ag2·acetone2 were confirmed
by X-ray crystallographic analysis. In combination with the
rod-like and the spherical morphologies observed by TEM
and SEM, the inter-conversion between [H·G·Ag]n and
H2·G·Ag2·acetone2 can be operated for infinite cycles. Our
work demonstrated the controlled formation, dissociation
and reformation of a polypseudorotaxane [H·G·Ag]n that
expands the possibilities for the development of precision
engineering of supramolecular polymers.
A competitive experiment was performed to show the
advantages of such reversible and waste-free chemorespon-
sive [H·G·Ag]n aided by the crown ether macrocycle. Specif-
ically, tetrabutylammonium iodine (TBAI) was employed as
a chemical stimulus instead of H to break up [H·G·Ag]n. As
shown in Figure 8, the diffusion coefficient D of [H·G·Ag]n
increased from 3.80 ꢁ 10À10 m2 sÀ1 to 9.33 ꢁ 10À10 m2 sÀ1 upon
adding one equivalent TBAI, while it decreased to 4.07 ꢁ
10À10 m2 sÀ1 with the further addition of AgSbF6. These results
revealed iodide-induced supramolecular depolymerization
and Ag+-induced repolymerization (Figures S24–S26). Never-
theless, the depolymerization process was accompanied by
the precipitation of AgI. Accordingly, the introduction of
invasive stimulus TBAI produced chemical waste, which is
disadvantageous for multiple-cycle supramolecular polymer-
ization/depolymerization transformations. The results vali-
dated the crucial role of H for the chemoresponsive supra-
molecular polymerization with infinite switching cycles.
Acknowledgements
This work was supported by the National Natural Science
Foundation of China (22035006, and 21922110) and the
Fundamental Research Funds for the Central Universities
(WK3450000005).
Conflict of Interest
Conclusion
The authors declare no conflict of interest.
A novel supramolecular polypseudorotaxane [H·G·Ag]n
was constructed with infinite chemo-switching capability. A
[2]pseudorotaxane HꢀG was first prepared based on H and
G. The crystal structure of HꢀG revealed that the two cyano
end groups of G were located outside the cavity of H, making
Keywords: chemoresponsiveness · host–guest systems ·
polypseudorotaxanes · supramolecular chemistry ·
supramolecular polymers
&&&&
www.angewandte.org
ꢀ 2021 Wiley-VCH GmbH
Angew. Chem. Int. Ed. 2021, 60, 2 – 8
These are not the final page numbers!

Angewandte
Research Articles
Chemie
[11] a) T. Ogoshi, S. Kanai, S. Fujinami, T. Yamagishi, Y. Nakamoto,
[1] a) A. J. Macinnis, Nature 1969, 224, 1221 – 1222; b) N. Netzer,
J. M. Goodenbour, A. David, K. A. Dittmar, R. B. Jones, J. R.
Schneider, D. Boone, E. M. Eves, M. R. Rosner, J. S. Gibbs, A.
Embry, B. Dolan, S. Das, H. D. Hickman, P. Berglund, J. R.
Bennink, J. W. Yewdell, T. Pan, Nature 2009, 462, 522 – 526; c) W.
Wang, Y.-X. Wang, H.-B. Yang, Chem. Soc. Rev. 2016, 45, 2656 –
2693; d) M. Leslie, Science 2019, 363, 1378 – 1380; e) M. Lee, R.
Rizzo, F. Surman, M. A. Zenobi-Wong, Chem. Rev. 2020, 120,
10950 – 11027.
J. Am. Chem. Soc. 2008, 130, 5022 – 5023; b) H. Zhang, X. Ma,
K. T. Nguyen, Y. Zhao, ACS Nano 2013, 7, 7853 – 7863; c) T.
Ogoshi, T. Kakuta, T. Yamagishi, Angew. Chem. Int. Ed. 2019,
58, 2197 – 2206; Angew. Chem. 2019, 131, 2219 – 2229; d) L.
Chen, Y. Cai, W. Feng, L. Yuan, Chem. Commun. 2019, 55,
7883 – 7898.
[12] a) K. Assaf, W. Nau, Chem. Soc. Rev. 2015, 44, 394 – 418; b) F.
Lutz, N. Lorenzo-Parodi, T. C. Schmidt, J. Niemeyer, Chem.
Commun. 2021, 57, 2887 – 2890.
[2] a) X.-Y. Hu, X. Wu, S. Wang, D. Chen, W. Xia, C. Lin, Y. Pan, L.
Wang, Polym. Chem. 2013, 4, 4292 – 4297; b) W. Zhang, H.-Y.
Zhang, Y.-H. Zhang, Y. Liu, Chem. Commun. 2015, 51, 16127 –
16130; c) P. Howlader, P. Das, E. Zangrando, P. S. Mukherjee, J.
Am. Chem. Soc. 2016, 138, 1668 – 1676; d) W. Zhou, Y. Chen, X.
Dai, H.-Y. Zhang, Y. Liu, Org. Lett. 2019, 21, 9363 – 9367; e) J.-R.
Wu, Y.-W. Yang, J. Am. Chem. Soc. 2019, 141, 12280 – 12287.
[3] a) C. Fouquey, J. M. Lehn, A. M. Levelut, Adv. Mater. 1990, 2,
254 – 257; b) R. P. Sijbesma, F. X. Beijer, L. Brunsveld, B.
Folmer, J. H. K. Ky Hirschberg, R. F. M. Lange, J. K. L. Lowe,
E. W. Meijer, Science 1997, 278, 1601 – 1604.
[4] a) X. Wang, G. Guerin, H. Wang, Y. Wang, I. Manners, M. A.
Winnik, Science 2007, 317, 644 – 647; b) J. Kang, D. Miyajima, T.
Mori, Y. Inoue, Y. Itoh, T. Aida, Science 2015, 347, 646 – 651;
c) A. K. Mandal, M. Gangopadhyay, A. Das, Chem. Soc. Rev.
2015, 44, 663 – 676; d) X.-H. Wang, N. Song, W. Hou, C. Wang, Y.
Wang, J. Tang, Y.-W. Yang, Adv. Mater. 2019, 31, 1903962; e) X.
Ji, F. Wang, X. Yan, S. Dong, F. Huang, Chin. J. Chem. 2020, 38,
1473 – 1479; f) X.-H. Wang, X.-Y. Lou, T. Lu, C. Wang, J. Tang, F.
Liu, Y. Wang, Y.-W. Yang, ACS Appl. Mater. Interfaces 2021, 13,
4593 – 4604.
[5] a) T. De Greef, M. Smulders, M. Wolffs, A. Schenning, R. P.
Sijbesma, E. W. Meijer, Chem. Rev. 2009, 109, 5687 – 5754; b) Y.
Deng, Q. Zhang, B. L. Feringa, H. Tian, D. Qu, Angew. Chem.
Int. Ed. 2020, 59, 5278 – 5283; Angew. Chem. 2020, 132, 5316 –
5321; c) S. Sarkar, A. Sarkar, S. George, Angew. Chem. Int. Ed.
2020, 59, 19841 – 19845; Angew. Chem. 2020, 132, 20013 – 20017.
[6] a) F. Hoeben, P. Jonkheijm, E. W. Meijer, A. Schenning, Chem.
Rev. 2005, 105, 1491 – 1546; b) M. Zhang, X. Yan, F. Huang, Z.
Niu, H. W. Gibson, Acc. Chem. Res. 2014, 47, 1995 – 2005; c) X.
Ji, M. Ahmed, L. Long, N. M. Khasab, F. Huang, J. L. Sessler,
Chem. Soc. Rev. 2019, 48, 2682 – 2697; d) J. Chen, K. Li, S. E.
Bonson, S. C. Zimmerman, J. Am. Chem. Soc. 2020, 142, 13966 –
13973; e) M. Wang, Q. Li, E. Li, J. Li, J. Zhou, F. Huang, Angew.
Chem. Int. Ed. 2021, 60, 8115 – 8120; Angew. Chem. 2021, 133,
8196 – 8201; f) Y. Han, Y. Yin, F. Wang, F. Wang, Angew. Chem.
Int. Ed. 2021, 60, 14076 – 14082; Angew. Chem. 2021, 133, 14195 –
14201.
[13] a) C. Gong, H. W. Gibson, Angew. Chem. Int. Ed. 1998, 37, 310 –
314; Angew. Chem. 1998, 110, 323 – 327; b) N. Yamaguchi, H. W.
Gibson, Angew. Chem. Int. Ed. 1999, 38, 143 – 147; Angew.
Chem. 1999, 111, 195 – 199; c) Z. Niu, H. W. Gibson, Chem. Rev.
2009, 109, 6024 – 6046; d) M. Lee, R. B. Moore, H. W. Gibson,
Macromolecules 2011, 44, 5987 – 5993; e) M. Arunachalam,
H. W. Gibson, Prog. Polym. Sci. 2014, 39, 1043 – 1073.
[14] A. Harada, J. Li, M. Kamachi, Nature 1992, 356, 325 – 327.
[15] a) F. Wang, J. Zhang, X. Ding, S. Dong, M. Liu, B. Zheng, S. Li,
L. Wu, Y. Yu, H. W. Gibson, F. Huang, Angew. Chem. Int. Ed.
2010, 49, 1090 – 1094; Angew. Chem. 2010, 122, 1108 – 1112; b) S.
Dong, Y. Luo, X. Yan, B. Zheng, X. Ding, Y. Yu, Z. Ma, Q. Zhao,
F. Huang, Angew. Chem. Int. Ed. 2011, 50, 1905 – 1909; Angew.
Chem. 2011, 123, 1945 – 1949; c) Z. Zhang, Y. Luo, J. Chen, S.
Dong, Y. Yu, Z. Ma, F. Huang, Angew. Chem. Int. Ed. 2011, 50,
1397 – 1401; Angew. Chem. 2011, 123, 1433 – 1437.
[16] a) Z. Huang, L. Yang, L. Liu, Z. Wang, O. A. Scherman, X.
Zhang, Angew. Chem. Int. Ed. 2014, 53, 5351 – 5355; Angew.
Chem. 2014, 126, 5455 – 5459; b) H. Chen, Z. Huang, H. Wu, J.-F.
Xu, X. Zhang, Angew. Chem. Int. Ed. 2017, 56, 16575 – 16578;
Angew. Chem. 2017, 129, 16802 – 16805; c) B. Qin, S. Zhang, Q.
Song, Z. Huang, J.-F. Xu, X. Zhang, Angew. Chem. Int. Ed. 2017,
56, 7639 – 7643; Angew. Chem. 2017, 129, 7747 – 7751; d) X.
Tang, H. Chen, Y. Kang, J.-F. Xu, X. Zhang, Angew. Chem. Int.
Ed. 2018, 57, 8545 – 8549; Angew. Chem. 2018, 130, 8681 – 8685.
[17] a) L. Fang, M. A. Olson, D. Benitez, E. Tkatchouk, W. A.
Goddard, J. F. Stoddart, Chem. Soc. Rev. 2010, 39, 17 – 29; b) Z.
Liu, S. K. M. Nalluri, J. F. Stoddart, Chem. Soc. Rev. 2017, 46,
2459 – 2478; c) Q.-H. Guo, Y. Qiu, X. Kuang, J. Liang, Y. Feng, L.
Zhang, Y. Jiao, D. Shen, R. D. Astumian, J. F. Stoddart, J. Am.
Chem. Soc. 2020, 142, 14443 – 14449.
[18] P. Ashton, R. Ballardini, V. Balzani, M. Belohradsky, M.
Gandolfi, D. Philp, L. Prodi, F. Raymo, M. Reddington, N.
Spencer, J. F. Stoddart, M. Venturi, D. Williams, J. Am. Chem.
Soc. 1996, 118, 4931 – 4951.
[19] D. Xia, X. Lv, K. Chen, P. Wang, Dalton Trans. 2019, 48, 9954 –
9958.
[20] Deposition Numbers 1981054, 1981055, and 1981056 (HꢀG,
[H·G·Ag]n, H2·G·Ag2·acetone2) contain the supplementary crys-
tallographic data for this paper. These data are provided free of
charge by the joint Cambridge Crystallographic Data Centre and
Fachinformationszentrum Karlsruhe Access Structures service
www.ccdc.cam.ac.uk/structures.
[7] a) C. J. Pederson, J. M. Lehn, D. J. Cram, Resonance 2001, 6, 71 –
79; b) R. M. Izatt, Chem. Soc. Rev. 2017, 46, 2380 – 2384.
[8] a) H. W. Gibson, N. Yamaguchi, J. Jones, J. Am. Chem. Soc. 2003,
125, 3522 – 3533; b) X. Lin, Y. Zheng, L. Jiang, H. Chen, Q.
Wang, J. Fluoresc. 2018, 28, 725 – 728.
[9] a) G. Crini, Chem. Rev. 2014, 114, 10940 – 10975; b) Y. Wu, R.
Shi, Y. Wu, J. Holcroft, Z. Liu, M. Frasconi, M. Wasielewski, H.
Li, J. F. Stoddart, J. Am. Chem. Soc. 2015, 137, 4111 – 4118.
[10] D.-S. Guo, Y. Liu, Chem. Soc. Rev. 2012, 41, 5907 – 5921.
Manuscript received: June 14, 2021
Accepted manuscript online: June 29, 2021
Version of record online: && &&
,
&&&&
Angew. Chem. Int. Ed. 2021, 60, 2 – 8
ꢀ 2021 Wiley-VCH GmbH
www.angewandte.org
&&&&
These are not the final page numbers!

Angewandte
Research Articles
Chemie
Research Articles
Supramolecular Chemistry
We report a novel polypseudorotaxane
[H·G·Ag]n as synergistically driven by
host–guest complexation and metal-
coordination interactions. It depoly-
merizes into a [3]pseudorotaxane
Y. Wu, L. Shangguan, Q. Li, J. Cao, Y. Liu,
Z. Wang, H. Zhu,* F. Wang,*
F. Huang*
&&&& — &&&&
H2·G·Ag2·acetone2 upon addition of H
and AgSF6, while it reforms with succes-
sive addition of G. The transformations
between [H·G·Ag]n and H2·G·Ag2·acetone2
can be switched for infinite cycles.
Chemoresponsive Supramolecular
Polypseudorotaxanes with Infinite
Switching Capability
&&&&
www.angewandte.org
ꢀ 2021 Wiley-VCH GmbH
Angew. Chem. Int. Ed. 2021, 60, 2 – 8
These are not the final page numbers!