Self-Assembly of Metallo-Supramolecules with Dissymmetrical Ligands and Characterization by Scanning Tunneling Microscopy

Article abstract of DOI:10.1021/jacs.0c12508

Asymmetrical and dissymmetrical structures are widespread and play a critical role in nature and life systems. In the field of metallo-supramolecular assemblies, it is still in its infancy for constructing artificial architectures using dissymmetrical bui

Full text of DOI:10.1021/jacs.0c12508

pubs.acs.org/JACS
Article
Self-Assembly of Metallo-Supramolecules with Dissymmetrical
Ligands and Characterization by Scanning Tunneling Microscopy
Junjuan Shi,# Yiming Li,# Xin Jiang, Hao Yu, Jiaqi Li, Houyu Zhang, Daniel J. Trainer, Saw Wai Hla,
Heng Wang, Ming Wang,* and Xiaopeng Li*
Cite This: J. Am. Chem. Soc. 2021, 143, 1224−1234
Read Online
sı
*
Metrics & More
Article Recommendations
Supporting Information
ACCESS
ABSTRACT: Asymmetrical and dissymmetrical structures are wide-
spread and play a critical role in nature and life systems. In the field of
metallo-supramolecular assemblies, it is still in its infancy for
constructing artificial architectures using dissymmetrical building
blocks. Herein, we report the self-assembly of supramolecular systems
based on two dissymmetrical double-layered ligands. With the aid of
ultra-high-vacuum, low-temperature scanning tunneling microscopy
(UHV-LT-STM), we were able to investigate four isomeric structures
corresponding to four types of binding modes of ligand LA with two
major conformations complexes A. The distribution of isomers
measured by STM and total binding energy of each isomer obtained
by density functional theory (DFT) calculations suggested that the most abundant isomer could be the most stable one with highest
total binding energy. Finally, through shortening the linker between inner and outer layers and the length of arms, the arrangement
of dissymmetrical ligand LB could be controlled within one binding mode corresponding to the single conformation for complexes
B.
difficult to prepare due to the multistep synthesis and tedious
purification. Moreover, because of the uncertain orientation of
each building block, multiple isomers could be generated during
self-assembly with similar physical properties and, thus,
hindering further isolation. Finally, even if the assembly with a
predominant arrangement is obtained, the characterization of
such complicated structures with dissymmetrical ligands would
remain a formidable challenge.
In the past decades, conventional characterization techniques
like NMR, electrospray ionization−mass spectrometry (ESI−
MS), traveling wave ion mobility−mass spectrometry (TWIM−
MS), and single-crystal X-ray diffraction have been well
established for characterizing supramolecules constructed by
highly symmetrical building blocks with large sizes and complex
structures.10b,13c,15b,21 However, these techniques become less
effective in investigating supramolecules assembled by dissym-
metrical ligands. For instance, the increased chemical environ-
ments caused by the low symmetry would significantly broaden
the NMR signals and make the spectrum obscure. Furthermore,
if all the isomeric structures with the same charges have similar
INTRODUCTION
■
Nature has developed impeccable systems for precise self-
assembly of well-organized bioarchitectures with desirable
functions. Inspired by nature, chemists have endeavored to
design and construct supramolecular structures with various
functions over the past decades.1,2 Among them, coordination-
driven self-assembly is a well-documented methodology for
preparing metallo-supramolecules with precisely controlled
shapes and sizes.3 Indeed a variety of 2D and 3D metallo-
supramolecules have been achieved.4−18 Most of these
structures, which have highly symmetrical shapes and geo-
metries, were obtained by self-assembly of symmetrical ligands,
due to the high predictability and controllability for ultimate
assemblies provided by the symmetrical building blocks.
Meanwhile, symmetrical ligands can effectively avoid the
generation of unexpected structures with similar thermody-
namic stability, especially for the self-assembly of multiple
ligands.
Asymmetrical and dissymmetrical structures are widespread
and play a critical role in nature and life systems. For example,
the dissymmetrical structures of proteins are crucial for many
specific functions of the cell.19 To date, however, very few
metallo-supramolecules were obtained by assembly of dissym-
metrical ligands but were limited to small sizes and simple
structures.20 Particularly, there exist three major challenges in
metallo-supramolecular systems based on dissymmetrical
ligands. First, the building blocks with low symmetry are usually
Received: December 1, 2020
Published: January 4, 2021
https://dx.doi.org/10.1021/jacs.0c12508
J. Am. Chem. Soc. 2021, 143, 1224−1234
© 2021 American Chemical Society
1224

Journal of the American Chemical Society
pubs.acs.org/JACS
Article
Scheme 1. (A) Self-Assembly of Dissymmetrical Ligand LA for the Construction of Complexes A Corresponding to Four Isomers
Based on Four Binding Modes and Two Major Conformations of LA and (B) Modeling Structures of Four Binding Modes in
Complexes A
structural collision cross sections, TWIM−MS is unable to
distinguish those isomers. In crystallographic analysis, the
isomers constructed by dissymmetrical ligands usually lead to
uncertain and irregular packing of supramolecules. As such, only
one or few isomers could crystallize out of a mixture of isomers
in the solutions. Therefore, effective characterization techniques
are highly demanded for investigating the supramolecules with
dissymmetrical ligands. In recent years, scanning tunneling
microscopy (STM) has emerged as a powerful tool to
characterize supramolecular assemblies, since it can directly
image each individual structure at submolecular resolution and
reflect the population of each isomer in the complex system.22
Among coordination-driven self-assembly, 2,2′:6′,2″-terpyr-
idine (tpy) has been widely used as a versatile building block for
constructing various symmetrical supramolecular architectur-
es.9c,e,10a,21g,23 In addition, the octahedral structures of the ⟨tpy-
M-tpy⟩ coordination sites with ca. 1 nm height on surface have
higher electron density than the flat organic skeletons; thus, they
can be clearly distinguished in STM and facilitate imaging the
structure and conformation of metallo-supramolecules.23e,f
Herein, we reported the design, synthesis, and self-assembly of
two dissymmetrical tetratopic tpy ligands (LA and LB) with
Zn(II). In our design, by adjusting the distance between inner
and outer layers of the ligands and the length of arms, the
symmetry and isomeric structures of the supramolecules are
expected to be controlled by the steric hindrance generated
during the self-assembly process. STM was utilized to investigate
the isomeric structure and obtain the distribution of each
isomer. The results showed that loose ligand LA generated four
hexameric isomers with the same composition as we expected
based on four types of binding modes during self-assembly
(Scheme 1). In comparison, the compact ligand LB self-
assembled into a mixture of hexamer, heptamer, and octamer
(Scheme 2) with only one coordination mode because of the
steric hindrance between the two layers.
Scheme 2. (A) Self-Assembly of Dissymmetrical Ligand LB
for the Construction of Complexes B1−B3 for Hexamer,
Heptamer, and Octamer, Respectively, with One Binding
Mode and (B) Modeling Structure of the Binding Mode in
Complexes B
RESULT AND DISCUSSION
■
Synthesis and Self-Assembly of Complexes A with
Four Binding Modes Followed by NMR and Mass
Spectrometry Characterization. LA was synthesized via a
multifold Sonogashira coupling reaction and purified by column
chromatography (the synthetic route is shown in Scheme S1 in
1225
https://dx.doi.org/10.1021/jacs.0c12508
J. Am. Chem. Soc. 2021, 143, 1224−1234

Journal of the American Chemical Society
pubs.acs.org/JACS
Article
the Supporting Information). All of the precursors and ligand
were fully characterized by NMR (1H, 13C, COSY, and
NOESY), ESI−MS, and MALDI-TOF mass spectrometry (see
details in the Supporting Information). The supramolecules A
were successfully prepared by mixing ligand LA and Zn(II) with
an exact stoichiometric ratio of 1:2 in CHCl3/CH3OH solution
at 50 °C for 12 h, followed by the addition of an excessive
amount of NH4PF6 to obtain a yellow precipitate in high yield. It
is worth noting that, because of the dissymmetrical feature, LA
could have two major conformations, which lead to four types of
binding modes and generate four isomers during self-assembly
(Scheme 1).
(DOSY) NMR spectrum of A (Figure S102) only displayed a
narrow band at log D = −9.72, perhaps owing to the similar sizes
and shapes of the isomers and the limits of instrument
resolution. The experimental diameter of A was calculated as
ca. 6.5 nm using the modified Stokes−Einstein equation,24
which agrees well with the theoretical prediction given by
modeling structures.
ESI−MS and TWIM−MS have emerged as effective methods
for analyzing the compositions and shapes of supramole-
cules.24,25 From the ESI−MS spectrum, one dominant set of
peaks with charge states from 16+ to 24+ was observed (Figure
−
2A), resulting from successive loss of the counterions (PF6 ).
The double-layered metallocycles were first characterized by
1H NMR spectroscopy. Due to the existence of multiple
isomeric components and slow tumbling motion of supra-
molecules on the NMR time scale, broadening signals were
observed in the 1H NMR spectrum (Figure 1B and Figure S97).
Figure 2. (A) ESI−MS and (B) TWIM−MS plot (m/z vs drift time) of
complexes A. The charge states of intact assemblies are marked.
Further investigation revealed that each isotope pattern of these
peaks matched well with the corresponding simulated isotope
pattern of A with a molecular weight of 15 063.06 Da (Figure 2A
and Figure S104). With four possible isomers in the system, the
TWIM−MS spectrum (Figure 2B), however, exhibited only one
narrow drift time distribution for each charge state, possibly on
account of slight structural differences between four isomers and
the resolution limits of the instrument.
Characterization of Complexes A by STM and
Theoretical Study by DFT Calculations. To further
investigate the structure of each isomer, high-resolution,
ultrahigh-vacuum, low-temperature scanning tunneling micros-
copy (UHV-LT-STM) was utilized to explore the possible
supramolecular isomers. The supramolecules were dissolved in
CH3CN and simply deposited on the surface of Ag(111) by
drop-casting. Due to the octahedral coordination structure and
high electron density, ⟨tpy-Zn(II)-tpy⟩ units give rise to a
relatively strong signal in the form of a bright dot when
Figure 1. 1H NMR spectra (600 MHz) of (A) ligand LA in CDCl3 and
(B) complexes A in CD3CN.
As shown by 2D-COSY and NOESY results (Figures S99 and
S101), four sets of proton signals from four different tpy units in
the aromatic region can be distinguished. Compared with ligand
LA, the signals of tpyA,B,C,D-H6,6″ protons showed a significant
upfield shift (Δδ ≈ 0.9 ppm) on account of the electronic
shielding effect,10a indicating the coordination of tpy units with
Zn(II). Meanwhile, all of the tpy-H3′,5′ protons exhibited a
diagnostic downfield (Δδ ≈ 0.3 ppm) shift. The −OCH2−
peaks of three alkyl chains (−OC6H13) at 4.75, 4.32, and 4.16
ppm were assigned to alkyl-Hd″, alkyl-Hd′, and alkyl-Hd, with an
integration ratio of 1:1:1. Note that although multiple isomers
existed simultaneously, the diffusion ordered spectroscopy
1226
https://dx.doi.org/10.1021/jacs.0c12508
J. Am. Chem. Soc. 2021, 143, 1224−1234

Journal of the American Chemical Society
pubs.acs.org/JACS
Article
Figure 3. (A, E) STM imaging of complexes A on the Ag (111) surface with a scale bar of 10 nm (green circle, A1; red circle, A2; white circle, A3; blue
circle, A4). (B, F, I, M) Enlarged STM images of complexes A1−A4 on the Ag (111) surface with a scale bar of 5 nm. (C, G, J, N) STM images of
highlighted circles coordination sites of complexes A1−A4 with a scale bar of 5 nm. (D, H, K, O) Representative energy-minimized structures from
molecular modeling of complexes A1−A4; alkyl chains were replaced by methoxy for clarity. (L) Distribution of four isomers based on the STM image
for complexes A.
compared with the case of intramolecular organic fragmen-
ts.23e,26 On account of the short distance between the two layers,
the signals of two adjacent ⟨tpy-Zn(II)-tpy⟩ units within
different layers were merged and formed the oval-shaped
lobes. By further investigating the direction, patterns, and
geometries of the bright lobes, as expected, four types of isomers
were observed from STM images (Figure 3 and Figures S154−
S156). As illustrated by the distribution of ⟨tpy-Zn(II)-tpy⟩
junctions, each type of isomer can be differentiated from others.
In order to confirm the shape and geometry of each isomer,
dotted lines were added for the detailed patterns of supra-
molecules (Figure 3 and Figure S154). The orientations of
adjacent inner and outer metal ions on the same side are shown
as red lines, and the blue lines link the outer margin of metal ions
and depict the shape of coordination site patterns. Thus, by
measuring the angles between the red lines and blue lines, four
isomers can be distinguished objectively (Figures S155−S158).
Regarding the symmetry of isomers’ structures, A1 is
centrosymmetric, but A3 is axisymmetric. It is worth noting
that the subtle differences of distribution of ⟨tpy-Zn(II)-tpy⟩
junctions from A1 and A3 can be distinguished from STM
imaging. STM imaging of supramolecules revealed clear images
of circular structures with diameters at ca. 6.5 nm (Figure
3B,F,I,M), which is consistent with the energy-minimized
structures from molecular modeling (Figure 3D,H,K,O). In
addition, the statistical data of each isomer (Figure 3L and
Figures S159−S161) indicated that the isomer of A1 has the
largest abundance (47%), followed by isomers A4 (30%), A3
(16%), and A2 (7%).
To gain further insights about the distribution of isomers
during the self-assembly of complexes A, total binding
(intermolecular interaction) energy was used to compare the
stabilities of different isomers by DFT simulation. During the
self-assembly of complexes A, four isomers were assembled
1227
https://dx.doi.org/10.1021/jacs.0c12508
J. Am. Chem. Soc. 2021, 143, 1224−1234

Journal of the American Chemical Society
pubs.acs.org/JACS
Article
because of the coexistence of two conformers of LA
corresponding to four binding modes (Figure S153A). Given
the large sizes of metallo-supramolecular isomers, we first
calculated the binding energy of each binding mode in order to
simplify the DFT calculation. Then, the total binding energy of
each isomer was estimated as the sum of individual binding
energies of six binding units within one structure. As shown in
Table S1, isomer A1 (EA1 = −787.253 623 2 Hartree) exhibited
the highest binding energy, followed by A4 (EA4
=
−787.247 005 8 Hartree), A3 (EA3 = −787.243 697 1 Hartree),
and A2 (EA4 = −787.240 279 8 Hartree). The order of total
binding energies (A1 > A4 > A3 > A2) of four isomers is
consistent with the order of experimental distribution of each
isomer collected by STM imaging (Figure 3L), suggesting that
the most abundant isomer A1 could be the most stable one with
the highest binding energy.
Synthesis and Self-Assembly of Complexes B with
One Binding Mode Followed by NMR and Mass
Spectrometry Characterization. During the self-assembly
of complexes A, four types of binding modes corresponding to
two conformations of LA coexisted and resulted in four
hexameric isomers. To further control the self-assembly of the
dissymmetrical building block, another compact ligand LB was
designed by shortening the linker between two layers and the
length of two arms. Through such a design, we aimed to control
the self-assembly of LB with one conformation by introducing
steric hindrance, which could result in one binding mode as
shown in Scheme 2B. Briefly, LB was obtained by the
combination of Sonogashira and Suzuki coupling reactions. It
was purified through a similar procedure as LA. Precursors and
LB were fully characterized by 1H, 13C, 2D COSY, 2D NOESY,
ESI−MS, and MALDI-TOF mass spectrometry.
Figure 4. (A) ESI−MS and (B) 2D ESI-TWIM−MS plot (m/z vs drift
time) of complexes B or Zn2xLBx (x = 6, 7, 8). The charge states of the
intact assemblies are marked.
The supramolecules were successfully prepared via the same
self-assembly procedure as for complexes A. The formation of
supramolecules was first characterized by 1H NMR, 2D COSY,
and NOESY NMR (Figures S143−S145). The 1H NMR
spectrum of assemblies shows four sets of tpy signals (Figure
S148). Similar characteristic upfield shifts of tpy-H6,6″ (Δδ ≈
0.98 ppm) and downfield shifts of tpy-H3′,5′ (Δδ ≈ 0.4 ppm)
were observed, indicating the coordination with Zn(II). The
−OCH2− of three alkyl chains (−OC6H13) showed peaks at
4.38, 4.34, and 4.25 ppm, which correspond to alkyl-Hd, alkyl-
Hd′, and alkyl-Hd″, with an integration ratio 1:1:1. DOSY NMR
spectroscopy (Figure S146) showed a broad diffusion coefficient
(log D = −9.69 to −9.74) for all the relevant peaks, suggesting
the existence of a mixture. As such, the supramolecular assembly
of LB could differ from the result of LA, due to the different
assembly behavior.
In ESI−MS and TWIM−MS spectra, three dominant
complexes (hexagon, heptagon, and octagon) were detected in
the system (Scheme 2), indicating that the compact structure of
LB indeed altered the self-assembly process. Briefly, the ESI−
MS spectrum showed three dominant sets of peaks with
continuous charge states from 10+ to 22+ (Figure 4A). The
isotope patterns of these peaks matched well with the
corresponding simulated isotope patterns of hexamer Zn12LB6
(B1), heptamer Zn14LB7 (B2), and octamer Zn16LB8 (B3) with
molecular weights of 14 631.06 Da, 17 069.57, and 19 505.08 Da
(Figures S149−S151), respectively. Due to the apparent size
difference of the hexamer, heptamer, and octamer, different
charge states of the hexagon, heptagon, and octagon with a
narrow time distribution were distinguished by TWIM−MS
(Figure 4B). Given that four isomers were identified during the
assembly between Zn(II) and LA, the characterization of
detailed structures for complexes B using STM turned out to be
necessary.
Characterization of Complexes B by STM. From the
STM images, hexamer, heptamer, and octamer were detected
(Figure 5 and Figures S162−S164) as observed by ESI−MS. On
account of the closer distance, the signals from two adjacent
⟨tpy-Zn(II)-tpy⟩ units have further merged into a circular lobe.
The sizes of supramolecules measured by STM agreed well with
the simulated structural sizes (Figure 5C,F,I). As shown by the
distribution of three isomers imaged by STM (Figure S165),
heptamer B2 is the foremost product (63.2%), followed by the
octamer (28%) and hexamer (8.8%). The highest population of
the heptamer further indicated the existence of substantial steric
hindrance in the cyclic structures and expanded the angles
between ligand arms to form larger rings. Interestingly, in
comparison with the four binding modes during the self-
assembly of LA with two major conformations, only one type of
conformation corresponding to a single type of binding mode
was found for the self-assembly of LB, which can be validated by
the uniform distribution in the STM image (Figure 5). The
average distribution of bright spots in Figure 5 indicated that the
short and long arms of the inner and outer layers are staggered in
the self-assembly process on account of the bulky size of ⟨tpy-
Zn(II)-tpy⟩ junctions and steric hindrance between them. STM
images also indicated that only spiral structures were generated
in the Zn2xLBx (x = 6, 7, 8) system. Therefore, by shortening the
linkers between two layers and length of arms to introduce steric
hindrance, the self-assembly behavior and conformations of
1228
https://dx.doi.org/10.1021/jacs.0c12508
J. Am. Chem. Soc. 2021, 143, 1224−1234

Journal of the American Chemical Society
pubs.acs.org/JACS
Article
Figure 5. (A, D, G) STM imaging of the complexes B on the Ag (111)
surface with a scale bar of 2 nm. (B, E, H) STM images of the
highlighted circles showing the coordination site of complexes B1−B3.
(C, F, I) Representative energy-minimized structures from molecular
modeling of complexes B1−B3; alkyl chains were replaced by methoxy.
dissymmetrical building blocks of supramolecules could be
further controlled.
Transmission Electron Microscopy (TEM) Character-
ization and Hierarchical Self-Assembly. Transmission
electron microscopy (TEM) experiments were also performed
to reveal the shapes and sizes of complexes A and B by
deposition of dilute CH3CN solutions (∼10−6 M) on the surface
of ultrathin carbon lacey support films on a copper grid. The
reasonably measured dimensions were observed for both
complexes A and B from TEM images (Figure 6A,E). The
zoomed-in TEM images (Figure 6B,F) showed ringlike
structures with hollow centers.
With the different assembled structures in hand, the
hierarchical self-assembly behaviors of supramolecules A and
B with long alkyl chains in different solvents were investigated.
All the samples are obtained by diffusing diethyl ether into the
solution of the complex (4 mg/mL in DMF). In Figure 6C, we
observed that A could further self-assemble in nanotube
structures, which were bound together to form fiberlike
aggregates. The diameter (ca. 6.5 nm) of some nanotubes
(Figure 6D) was consistent with that of individual supra-
molecules A from the energy-minimized structure. The
hierarchical self-assembly result of nanofiber structures was
likely attributed to multiple intermolecular interactions, such as
π−π stacking, and CH−π hydrophobic/hydrophilic interac-
tions.27 Due to the existence of isomers with similar size, it is
hard to recognize the molecular structures within fibers.
Different with the hierarchical self-assembly behavior of A,
spherical aggregates with diameters of about 50−250 nm were
observed in the B system (Figure 6G,H). The different
hierarchical self-assembly behaviors could be attributed to the
following two aspects: (i) the reduced distance between inner
and outer layers inhibits π−π stacking owing to the pseudo-
octahedral configuration of tpy with transition metal ions; and
(ii) the interior angles of heptamer and octamer are different
from the designed 120° on the backbone, which may lead to
Figure 6. (A, E) TEM image of complexes A and B with a scale bar of
100 nm. (B, F) Enlarged TEM image of A and B with a scale bar of 20
nm. (C) TEM images of nanofiber structures formed by A with a scale
bar of 100 nm. (D) Enlarged TEM images of nanofiber structures
formed by A with a scale bar of 20 nm. (G) TEM images of spherical
aggregates of B with a scale bar of 500 nm. (H) TEM images of
spherical aggregates of B with a scale bar of 250 nm.
nonplanar structures and which hampered the hierarchical
packing.
CONCLUSION
■
In summary, two novel supramolecular systems were success-
fully assembled through the coordination between dissym-
metrical double-layered tetratopic 2,2′:6′,2″-terpyridine ligands
and Zn(II). In addition to the conventional characterization
techniques (including NMR, MS, and TEM), UHV-LT-STM
was utilized to investigate the structures of isomeric systems at
the submolecular level. The STM statistical data and DFT
calculation revealed that four hexameric isomers existed in the
self-assembly of supramolecules A because of the four types of
1229
https://dx.doi.org/10.1021/jacs.0c12508
J. Am. Chem. Soc. 2021, 143, 1224−1234

Journal of the American Chemical Society
pubs.acs.org/JACS
Article
binding modes during the self-assembly of ligand LA with two
major conformations. Among all isomers, A1 had the highest
total binding energy in the DFT calculation and the highest
abundance in STM imaging statistical results. Different from the
self-assembly of supramolecules A, the hexamer, heptamer, and
octamer were generated in the self-assembly of supramolecules
B with composition Zn2xLBx (x = 6, 7, and 8). STM images
further revealed that only a single conformation corresponding
to one binding mode was found for ligand LB. Among these
spiral structures, the heptamer was the foremost product
followed by the octamer and hexamer. As such, the self-
assembly behavior and structures of supramolecules could be
controlled by adjusting the length of arms and the distance of
two layers. This work offered a promising avenue for the design
and characterization of supramolecular architectures with
dissymmetrical ligands and sheds light on the insight of
coordination-driven self-assembly processes.
Daniel J. Trainer − Nanoscience and Technology Division,
Argonne National Laboratory, Lemont, Illinois 60439, United
States
Saw Wai Hla − Nanoscience and Technology Division, Argonne
National Laboratory, Lemont, Illinois 60439, United States
Heng Wang − College of Chemistry and Environmental
Engineering, Shenzhen University, Shenzhen, Guangdong
518055, China
Complete contact information is available at:
https://pubs.acs.org/10.1021/jacs.0c12508
Author Contributions
#J.S. and Y.L. contributed equally.
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
■
We gratefully acknowledge the support from the National
Natural Science Foundation of China (22071079 for M.W.) and
mass spectrometry characterization by Molecular Scale
Laboratories. X.L. acknowledges the support from Tencent
Founders Alumni Foundation.
ASSOCIATED CONTENT
■
sı
* Supporting Information
The Supporting Information is available free of charge at
https://pubs.acs.org/doi/10.1021/jacs.0c12508.
Synthetic details and characterizations of ligands and
complexes including NMR, ESI−MS, TWIM−MS, DFT
calculation, and STM (PDF)
REFERENCES
■
(1) (a) Cram, D. J. The Design of Molecular Hosts, Guests, and Their
Complexes. Angew. Chem., Int. Ed. Engl. 1988, 27 (8), 1009−1020.
(b) Pedersen, C. J. The Discovery of Crown Ethers. Angew. Chem., Int.
Ed. Engl. 1988, 27 (8), 1021−1027. (c) Lehn, J.-M. Supramolecular
Chemistry-Scope and Perspectives Molecules, Supermolecules, and
Molecular Devices. Angew. Chem., Int. Ed. Engl. 1988, 27 (1), 89−112.
(2) (a) Philp, D.; Stoddart, J. F. Self-Assembly in Natural and
Unnatural Systems. Angew. Chem., Int. Ed. Engl. 1996, 35 (11), 1154−
1196. (b) Forgan, R. S.; Sauvage, J.-P.; Stoddart, J. F. Chemical
Topology: Complex Molecular Knots, Links, and Entanglements.
Chem. Rev. 2011, 111 (9), 5434−5464. (c) Hargrove, A. E.; Nieto, S.;
Zhang, T.; Sessler, J. L.; Anslyn, E. V. Artificial Receptors for the
Recognition of Phosphorylated Molecules. Chem. Rev. 2011, 111 (11),
6603−6782.
AUTHOR INFORMATION
■
Corresponding Authors
Ming Wang − State Key Laboratory of Supramolecular
Structure and Materials, College of Chemistry, Jilin University,
Changchun, Jilin 130012, China; orcid.org/0000-0002-
5332-0804; Email: mingwang358@jlu.edu.cn
Xiaopeng Li − College of Chemistry and Environmental
Engineering and Shenzhen University General Hospital,
Clinical Medical Academy, Shenzhen University, Shenzhen,
Guangdong 518055, China; orcid.org/0000-0001-9655-
9551; Email: xiaopengli@szu.edu.cn
(3) (a) Caulder, D. L.; Raymond, K. N Supermolecules by Design. Acc.
Chem. Res. 1999, 32 (11), 975−982. (b) Hofmeier, H.; Schubert, U. S.
Recent Developments in the Supramolecular Chemistry of Terpyr-
idine-Metal Complexes. Chem. Soc. Rev. 2004, 33 (6), 373−399.
Authors
Junjuan Shi − State Key Laboratory of Supramolecular
Structure and Materials, College of Chemistry, Jilin University,
Changchun, Jilin 130012, China; College of Chemistry and
Environmental Engineering, Shenzhen University, Shenzhen,
Guangdong 518055, China
Yiming Li − College of Chemistry and Environmental
Engineering, Shenzhen University, Shenzhen, Guangdong
518055, China; Department of Chemistry, University of South
Florida, Tampa, Florida 33620, United States
Xin Jiang − State Key Laboratory of Supramolecular Structure
and Materials, College of Chemistry, Jilin University,
Changchun, Jilin 130012, China
Hao Yu − State Key Laboratory of Supramolecular Structure
and Materials, College of Chemistry, Jilin University,
Changchun, Jilin 130012, China
Jiaqi Li − State Key Laboratory of Supramolecular Structure and
Materials, College of Chemistry, Jilin University, Changchun,
Jilin 130012, China
(c) Wild, A.; Winter, A.; Schlutter, F.; Schubert, U. S. Advances in the
̈
Field of π-Conjugated 2,2′:6′,2″-Terpyridines. Chem. Soc. Rev. 2011, 40
(3), 1459−1511.
(4) (a) Wurthner, F.; You, C.-C.; Saha-Moller, C. R. Metal-
̈
̈
losupramolecular Squares: From Structure to Function. Chem. Soc.
Rev. 2004, 33 (3), 133−146. (b) Meyer, C. D.; Joiner, C. S.; Stoddart, J.
F. Template-Directed Synthesis Employing Reversible Imine Bond
Formation. Chem. Soc. Rev. 2007, 36 (11), 1705−1723. (c) Chakra-
barty, R.; Mukherjee, P. S.; Stang, P. J. Supramolecular Coordination:
Self-Assembly of Finite Two- and Three-Dimensional Ensembles.
Chem. Rev. 2011, 111 (11), 6810−6918. (d) Han, M.; Engelhard, D.
M.; Clever, G. H. Self-Assembled Coordination Cages Based on
Banana-Shaped Ligands. Chem. Soc. Rev. 2014, 43 (6), 1848−1860.
(e) Cook, T. R.; Stang, P. J. Recent Developments in the Preparation
and Chemistry of Metallacycles and Metallacages via Coordination.
Chem. Rev. 2015, 115 (15), 7001−7045. (f) Newkome, G. R.;
Moorefield, C. N. From 1→3 Dendritic Designs to Fractal Supra-
macromolecular Constructs: Understanding the Pathway to the
Sierpinski Gasket. Chem. Soc. Rev. 2015, 44 (12), 3954−3967.
(g) Chen, L.-J.; Yang, H.-B.; Shionoya, M. Chiral Metallosupramo-
lecular Architectures. Chem. Soc. Rev. 2017, 46 (9), 2555−2576.
(h) Chakraborty, S.; Newkome, G. R. Terpyridine-Based Metal-
losupramolecular Constructs: Tailored Monomers to Precise 2D-
Motifs and 3D-Metallocages. Chem. Soc. Rev. 2018, 47 (11), 3991−
Houyu Zhang − State Key Laboratory of Supramolecular
Structure and Materials, College of Chemistry, Jilin University,
Changchun, Jilin 130012, China; orcid.org/0000-0003-
0360-6035
1230
https://dx.doi.org/10.1021/jacs.0c12508
J. Am. Chem. Soc. 2021, 143, 1224−1234

Journal of the American Chemical Society
pubs.acs.org/JACS
Article
4016. (i) Pan, M.; Wu, K.; Zhang, J.-H.; Su, C.-Y. Chiral Metal-Organic
Cages/Containers (MOCs): From Structural and Stereochemical
Design to Applications. Coord. Chem. Rev. 2019, 378, 333−349.
(j) Wang, W.; Wang, Y.-X.; Yang, H.-B. Supramolecular Trans-
formations within Discrete Coordination-Driven Supramolecular
Architectures. Chem. Soc. Rev. 2016, 45 (9), 2656−2693. (k) Gao,
W.-X.; Feng, H.-J.; Guo, B.-B.; Lu, Y.; Jin, G.-X. Coordination-Directed
Construction of Molecular Links. Chem. Rev. 2020, 120 (13), 6288−
6325. (l) Jin, Y.; Zhang, Q.; Zhang, Y.; Duan, C. Electron Transfer in
the Confined Environments of Metal-Organic Coordination Supra-
molecular Systems. Chem. Soc. Rev. 2020, 49 (15), 5561−5600.
(m) Sun, Y.; Chen, C.; Liu, J.; Stang, P. J. Recent developments in the
construction and applications of platinum-based metallacycles and
metallacages via coordination. Chem. Soc. Rev. 2020, 49 (12), 3889−
3919.
(5) (a) Stang, P. J.; Olenyuk, B. Self-Assembly, Symmetry, and
Molecular Architecture: Coordination as the Motif in the Rational
Design of Supramolecular Metallacyclic Polygons and Polyhedra. Acc.
Chem. Res. 1997, 30 (12), 502−518. (b) Seidel, S. R.; Stang, P. J. High-
Symmetry Coordination Cages via Self-Assembly. Acc. Chem. Res. 2002,
35 (11), 972−983. (c) Fujita, M.; Tominaga, M.; Hori, A.; Therrien, B.
Coordination Assemblies from a Pd(II)-Cornered Square Complex.
Acc. Chem. Res. 2005, 38 (4), 369−378. (d) Nitschke, J. R.
Construction, Substitution, and Sorting of Metallo-Organic Structures
via Subcomponent Self-Assembly. Acc. Chem. Res. 2007, 40 (2), 103−
112. (e) Castilla, A. M.; Ramsay, W. J.; Nitschke, J. R. Stereochemistry
in Subcomponent Self-Assembly. Acc. Chem. Res. 2014, 47 (7), 2063−
2073. (f) Jansze, S. M.; Severin, K. Clathrochelate Metalloligands in
Supramolecular Chemistry and Materials Science. Acc. Chem. Res. 2018,
51 (9), 2139−2147.
B.; Whiteford, J. A.; Stang, P. J. Design and Study of Synthetic Chiral
Nanoscopic Assemblies. Preparation and Characterization of Optically
Active Hybrid, Iodonium-Transition-Metal and All-Transition-Metal
Macrocyclic Molecular Squares. J. Am. Chem. Soc. 1996, 118 (35),
8221−8230. (f) Stang, P. J.; Olenyuk, B. Directed Self-Assembly of
Chiral, Optically Active Macrocyclic Tetranuclear Molecular Squares.
Angew. Chem., Int. Ed. Engl. 1996, 35 (7), 732−736.
(9) (a) Perera, S.; Li, X.; Soler, M.; Schultz, A.; Wesdemiotis, C.;
Moorefield, C. N.; Newkome, G. R. Hexameric Palladium(II)
Terpyridyl Metallomacrocycles: Assembly with 4,4′-Bipyridine and
Characterization by TWIM Mass Spectrometry. Angew. Chem., Int. Ed.
2010, 49 (37), 6539−6544. (b) Wang, M.; Wang, C.; Hao, X.-Q.; Liu,
J.; Li, X.; Xu, C.; Lopez, A.; Sun, L.; Song, M.-P.; Yang, H.-B.; Li, X.
Hexagon Wreaths: Self-Assembly of Discrete Supramolecular Fractal
Architectures Using Multitopic Terpyridine Ligands. J. Am. Chem. Soc.
2014, 136 (18), 6664−6671. (c) Li, Y.; Jiang, Z.; Wang, M.; Yuan, J.;
Liu, D.; Yang, X.; Chen, M.; Yan, J.; Li, X.; Wang, P. Giant, Hollow 2D
Metalloarchitecture: Stepwise Self-Assembly of a Hexagonal Supra-
molecular Nut. J. Am. Chem. Soc. 2016, 138 (31), 10041−10046.
(d) Yan, X. Z.; Wang, M.; Cook, T. R.; Zhang, M. M.; Saha, M. L.;
Zhou, Z. X.; Li, X. P.; Huang, F. H.; Stang, P. J. Light-Emitting
Superstructures with Anion Effect: Coordination-Driven Self-Assembly
of Pure Tetraphenylethylene Metallacycles and Metallacages. J. Am.
Chem. Soc. 2016, 138 (13), 4580−4588. (e) Wang, M.; Wang, K.;
Wang, C.; Huang, M.; Hao, X.-Q.; Shen, M.-Z.; Shi, G. Q.; Zhang, Z.;
Song, B.; Cisneros, A.; Song, M.-P.; Xu, B.; Li, X. Self-Assembly of
Concentric Hexagons and Hierarchical Self-Assembly of Supra-
molecular Metal-Organic Nanoribbons at the Solid/Liquid Interface.
J. Am. Chem. Soc. 2016, 138 (29), 9258−9268.
(10) (a) Wang, J.-L.; Li, X.; Lu, X.; Hsieh, I.-F.; Cao, Y.; Moorefield, C.
N.; Wesdemiotis, C.; Cheng, S. Z.; Newkome, G. R. Stoichiometric
Self-Assembly of Shape-Persistent 2D Complexes: A Facile Route to a
Symmetric Supramacromolecular Spoked Wheel. J. Am. Chem. Soc.
2011, 133 (30), 11450−11453. (b) Lu, X.; Li, X.; Cao, Y.; Schultz, A.;
Wang, J.-L.; Moorefield, C. N.; Wesdemiotis, C.; Cheng, S. Z.;
Newkome, G. R. Self-Assembly of a Supramolecular, Three-Dimen-
sional, Spoked, Bicycle-Like Wheel. Angew. Chem., Int. Ed. 2013, 52
(30), 7728−7731. (c) Lu, X.; Li, X.; Guo, K.; Wang, J.; Huang, M.;
Wang, J.-L.; Xie, T.-Z.; Moorefield, C. N.; Cheng, S. Z.; Wesdemiotis,
C.; Newkome, G. R. One Ligand in Dual Roles: Self-Assembly of a Bis-
Rhomboidal-Shaped, Three-Dimensional Molecular Wheel. Chem. -
Eur. J. 2014, 20 (41), 13094−13098.
(6) (a) Holliday, B. J.; Mirkin, C. A. Strategies for the Construction of
Supramolecular Compounds through Coordination Chemistry. Angew.
Chem., Int. Ed. 2001, 40 (11), 2022−2043. (b) Sepehrpour, H.; Fu, W.;
Sun, Y.; Stang, P. J. Biomedically Relevant Self-Assembled Metalla-
cycles and Metallacages. J. Am. Chem. Soc. 2019, 141 (36), 14005−
14020.
(7) (a) Schweiger, M.; Seidel, S. R.; Arif, A. M.; Stang, P. J. The Self-
Assembly of an Unexpected, Unique Supramolecular Triangle
Composed of Rigid Subunits. Angew. Chem., Int. Ed. 2001, 40 (18),
3467−3469. (b) Kryschenko, Y. K.; Seidel, S. R.; Arif, A. M.; Stang, P. J.
Coordination-Driven Self-Assembly of Predesigned Supramolecular
Triangles. J. Am. Chem. Soc. 2003, 125 (17), 5193−5198. (c) Heo, J.;
Jeon, Y.-M.; Mirkin, C. A. Reversible Interconversion of Homochiral
Triangular Macrocycles and Helical Coordination Polymers. J. Am.
Chem. Soc. 2007, 129 (25), 7712−7713. (d) Zangrando, E.; Casanova,
M.; Alessio, E. Trinuclear Metallacycles: Metallatriangles and Much
More. Chem. Rev. 2008, 108 (12), 4979−5013. (e) Schmittel, M.;
Mahata, K. A Fully Dynamic Five-Component Triangle via Self-Sorting.
Chem. Commun. 2010, 46 (23), 4163−4165. (f) Liu, Z.; Liu, G.; Wu, Y.;
Cao, D.; Sun, J.; Schneebeli, S. T.; Nassar, M. S.; Mirkin, C. A.;
Stoddart, J. F. Assembly of Supramolecular Nanotubes from Molecular
Triangles and 1,2-Dihalohydrocarbons. J. Am. Chem. Soc. 2014, 136
(47), 16651−16660. (g) Wood, D. M.; Meng, W. J.; Ronson, T. K.;
Stefankiewicz, A. R.; Sanders, J. K. M.; Nitschke, J. R. Guest-Induced
Transformation of a Porphyrin-Edged FeII L6 Capsule into a CuIFeII L4
(11) (a) Toyota, S.; Woods, C. R.; Benaglia, M.; Haldimann, R.;
̈
Warnmark, K.; Hardcastle, K.; Siegel, J. S. Tetranuclear Copper(I)-
Biphenanthroline Gridwork: Violation of the Principle of Maximal
Donor Coordination Caused by Intercalation and CH-to-N Forces.
Angew. Chem., Int. Ed. 2001, 40 (4), 751−754. (b) Schmittel, M.;
Kalsani, V.; Fenske, D.; Wiegrefe, A. Self-Assembly of Heteroleptic [2 ×
2] and [2 × 3] Nanogrids. Chem. Commun. 2004, No. 5, 490−491.
(c) Schmittel, M.; Kalsani, V.; Bats, J. W. Metal-Driven and Covalent
Synthesis of Supramolecular Grids from Racks: A Convergent
Approach to Heterometallic and Heteroleptic Nanostructures. Inorg.
̀
Chem. 2005, 44 (12), 4115−4117. (d) Dhers, S.; Mondal, A.; Aguila,
D.; Ramirez, J.; Vela, S.; Dechambenoit, P.; Rouzieres, M.; Nitschke, J.
R.; Clerac, R.; Lehn, J. M. Spin State Chemistry: Modulation of Ligand
pK(a) by Spin State Switching in a [2 × 2] Iron(II) Grid-Type
Complex. J. Am. Chem. Soc. 2018, 140 (26), 8218−8227.
4
2
Fullerene Receptor. Angew. Chem., Int. Ed. 2015, 54 (13), 3988−3992.
(8) (a) Fujita, M.; Yazaki, J.; Ogura, K. Preparation of a Macrocyclic
Polynuclear Complex, [(en)Pd(4,4′-Bpy)]4(NO3)8,1 Which Recog-
nizes an Organic Molecule in Aqueous Media. J. Am. Chem. Soc. 1990,
112 (14), 5645−5647. (b) Stang, P. J.; Cao, D. H. Transition Metal
Based Cationic Molecular Boxes. Self-Assembly of Macrocyclic
Platinum(II) and Palladium(II) Tetranuclear Complexes. J. Am.
Chem. Soc. 1994, 116 (11), 4981−4982. (c) Stang, P. J.; Cao, D. H.;
Saito, S.; Arif, A. M. Self-Assembly of Cationic, Tetranuclear, Pt(II) and
Pd(II) Macrocyclic Squares. X-Ray Crystal Structure of [Pt2+(dppp)-
(4,4′-bipyridyl)2-OSO2CF3]4. J. Am. Chem. Soc. 1995, 117 (23), 6273−
6283. (d) Fujita, M.; Sasaki, O.; Mitsuhashi, T.; Fujita, T.; Yazaki, J.;
Yamaguchi, K.; Ogura, K. On the Structure of Transition-Metal-Linked
Molecular Squares. Chem. Commun. 1996, 1535−1536. (e) Olenyuk,
(12) (a) Caulder, D. L.; Powers, R. E.; Parac, T. N.; Raymond, K. N.
The Self-Assembly of a Predesigned Tetrahedral M4L6 Supramolecular
Cluster. Angew. Chem., Int. Ed. 1998, 37 (13−14), 1840−1843. (b) Mal,
P.; Schultz, D.; Beyeh, K.; Rissanen, K.; Nitschke, J. R. An Unlockable-
Relockable Iron Cage by Subcomponent Self-Assembly. Angew. Chem.,
Int. Ed. 2008, 47 (43), 8297−8301. (c) Black, S. P.; Stefankiewicz, A.
R.; Smulders, M. M. J.; Sattler, D.; Schalley, C. A.; Nitschke, J. R.;
Sanders, J. K. M. Generation of a Dynamic System of Three-
Dimensional Tetrahedral Polycatenanes. Angew. Chem., Int. Ed. 2013,
52 (22), 5749−5752. (d) Ludlow, J. M., III; Xie, T.; Guo, Z.; Guo, K.;
Saunders, M. J.; Moorefield, C. N.; Wesdemiotis, C.; Newkome, G. R.
Directed Flexibility: Self-Assembly of a Supramolecular Tetrahedron.
1231
https://dx.doi.org/10.1021/jacs.0c12508
J. Am. Chem. Soc. 2021, 143, 1224−1234

Journal of the American Chemical Society
pubs.acs.org/JACS
Article
Chem. Commun. 2015, 51 (18), 3820−3823. (e) McConnell, A. J.;
(17) (a) Barran, P. E.; Cole, H. L.; Goldup, S. M.; Leigh, D. A.;
McGonigal, P. R.; Symes, M. D.; Wu, J.; Zengerle, M. Active-Metal
Template Synthesis of a Molecular Trefoil Knot. Angew. Chem., Int. Ed.
2011, 50 (51), 12280−12284. (b) Romuald, C.; Coutrot, F.
Combining Coordination Chemistry and Catalysis to Tie a Knot by
an Active-Metal Template Strategy. Angew. Chem., Int. Ed. 2012, 51
(11), 2544−2545. (c) Leigh, D. A.; Pirvu, L.; Schaufelberger, F.;
Tetlow, D. J.; Zhang, L. Securing a Supramolecular Architecture by
Tying a Stopper Knot. Angew. Chem., Int. Ed. 2018, 57 (33), 10484−
10488.
Aitchison, C. M.; Grommet, A. B.; Nitschke, J. R. Subcomponent
Exchange Transforms an FeII L4 Cage from High- to Low-Spin,
4
Switching Guest Release in a Two-Cage System. J. Am. Chem. Soc. 2017,
139 (18), 6294−6297. (f) Liu, D.; Chen, M.; Li, K.; Li, Z.; Huang, J.;
Wang, J.; Jiang, Z.; Zhang, Z.; Xie, T.; Newkome, G. R.; Wang, P. Giant
Truncated Metallo-Tetrahedron with Unexpected Supramolecular
Aggregation Induced Emission Enhancement. J. Am. Chem. Soc.
2020, 142 (17), 7987−7994.
̈
(13) (a) Olenyuk, B.; Whiteford, J. A.; Fechtenkotter, A.; Stang, P. J.
(18) (a) Sun, Q.-F.; Iwasa, J.; Ogawa, D.; Ishido, Y.; Sato, S.; Ozeki, T.;
Sei, Y.; Yamaguchi, K.; Fujita, M. Self-Assembled M24L48 Polyhedra and
Their Sharp Structural Switch Upon Subtle Ligand Variation. Science
2010, 328 (5982), 1144−1147. (b) Bunzen, J.; Iwasa, J.;
Bonakdarzadeh, P.; Numata, E.; Rissanen, K.; Sato, S.; Fujita, M.
Self-Assembly of M24L48 Polyhedra Based on Empirical Prediction.
Angew. Chem., Int. Ed. 2012, 51 (13), 3161−3163. (c) Xie, T.-Z.; Liao,
S.-Y.; Guo, K.; Lu, X.; Dong, X.; Huang, M.; Moorefield, C. N.; Cheng,
S. Z.; Liu, X.; Wesdemiotis, C.; Newkome, G. R. Construction of a
Highly Symmetric Nanosphere via a One-Pot Reaction of a
Tristerpyridine Ligand with Ru(II). J. Am. Chem. Soc. 2014, 136
(23), 8165−8168. (d) Wang, Q.-Q.; Gonell, S.; Leenders, S. H. A. M.;
Self-Assembly of Nanoscale Cuboctahedraby Coordination Chemistry.
Nature 1999, 398 (6730), 796−799. (b) Sun, Q.-F.; Sato, S.; Fujita, M.
An M18L24 Stellated Cuboctahedron through Post-Stellation of an
M12L24 Core. Nat. Chem. 2012, 4 (4), 330−333. (c) Xie, T.-Z.; Guo, K.;
Guo, Z.; Gao, W.-Y.; Wojtas, L.; Ning, G.-H.; Huang, M.; Lu, X.; Li, J.-
Y.; Liao, S.-Y.; Chen, Y.-S.; Moorefield, C. N.; Saunders, M. J.; Cheng,
S. Z.; Wesdemiotis, C.; Newkome, G. R. Precise Molecular Fission and
Fusion: Quantitative Self-Assembly and Chemistry of a Metallo-
Cuboctahedron. Angew. Chem., Int. Ed. 2015, 54 (32), 9224−9229.
(d) Xie, T.-Z.; Endres, K. J.; Guo, Z.; Ludlow, J. M., III; Moorefield, C.
N.; Saunders, M. J.; Wesdemiotis, C.; Newkome, G. R. Controlled
Interconversion of Superposed-Bistriangle, Octahedron, and Cubocta-
hedron Cages Constructed Using a Single, Terpyridinyl-Based
Polyligand and Zn2+. J. Am. Chem. Soc. 2016, 138 (38), 12344−12347.
(14) (a) Meng, W. J.; Breiner, B.; Rissanen, K.; Thoburn, J. D.; Clegg,
J. K.; Nitschke, J. R. A Self-Assembled M8L6 Cubic Cage That
Selectively Encapsulates Large Aromatic Guests. Angew. Chem., Int. Ed.
2011, 50 (15), 3479−3483. (b) Ramsay, W. J.; Ronson, T. K.; Clegg, J.
K.; Nitschke, J. R. Bidirectional Regulation of Halide Binding in a
Heterometallic Supramolecular Cube. Angew. Chem., Int. Ed. 2013, 52
(50), 13439−13443. (c) Ramsay, W. J.; Nitschke, J. R. Two Distinct
́ ́
Durr, M.; Ivanovic-Burmazovic, I.; Reek, J. N. H. Self-Assembled
̈
Nanospheres with Multiple Endohedral Binding Sites Pre-Organize
Catalysts and Substrates for Highly Efficient Reactions. Nat. Chem.
2016, 8 (3), 225−230. (e) Chen, Y.-S.; Solel, E.; Huang, Y.-F.; Wang,
C.-L.; Tu, T.-H.; Keinan, E.; Chan, Y.-T. Chemical Mimicry of Viral
Capsid Self-Assembly via Corannulene-Based Pentatopic Tectons. Nat.
Commun. 2019, 10 (1), 3443.
(19) (a) Doolittle, R. F. Proteins. Sci. Am. 1985, 253, 88−99. (b) Xu,
Z.; Horwich, A. L.; Sigler, P. B. The Crystal Structure of the Asymmetric
Groel-Groes-(Adp)7 Chaperonin Complex. Nature 1997, 388 (6644),
741−750. (c) Branden; Ivar, C.; Tooze, J. Introduction to Protein
Structure; Garland Science, 2012.
16+
Allosteric Active Sites Regulate Guest Binding within a Fe8Mo12
Cubic Receptor. J. Am. Chem. Soc. 2014, 136 (19), 7038−7043.
(d) Wang, M.; Wang, C.; Hao, X.-Q.; Li, X.; Vaughn, T. J.; Zhang, Y.-Y.;
Yu, Y.; Li, Z.-Y.; Song, M.-P.; Yang, H.-B.; Li, X. From Trigonal
Bipyramidal to Platonic Solids: Self-Assembly and Self-Sorting Study of
Terpyridine-Based 3D Architectures. J. Am. Chem. Soc. 2014, 136 (29),
(20) (a) Qin, Z.; Jennings, M. C.; Puddephatt, R. J. Stacked Molecular
Triangles: Self-Assembly Using Coordination Chemistry and Hydro-
gen Bonding. Chem. Commun. 2001, 24, 2676−2677. (b) Chi, K.-W.;
Addicott, C.; Arif, A. M.; Stang, P. J. Ambidentate Pyridyl-Carboxylate
Ligands in the Coordination-Driven Self-Assembly of 2D Pt Macro-
cycles: Self-Selection for a Single Isomer. J. Am. Chem. Soc. 2004, 126
(50), 16569−16574. (c) Ghosh, S.; Mukherjee, P. S. Self-Assembly of
Metal-Organic Hybrid Nanoscopic Rectangles. Dalton Trans. 2007,
2542−2546. (d) Zhao, L.; Northrop, B. H.; Zheng, Y. R.; Yang, H. B.;
Lee, H. J.; Lee, Y. M.; Park, J. Y.; Chi, K. W.; Stang, P. J. Self-Selection in
the Self-Assembly of Isomeric Supramolecular Squares from Unsym-
metrical Bis(4-Pyridyl)Acetylene Ligands. J. Org. Chem. 2008, 73 (17),
6580−6586. (e) Zheng, Y.-R.; Northrop, B. H.; Yang, H.-B.; Zhao, L.;
Stang, P. J. Geometry Directed Self-Selection in the Coordination-
Driven Self-Assembly of Irregular Supramolecular Polygons. J. Org.
Chem. 2009, 74, 3554−3557. (f) Sato, T.; Higuchi, M. An Alternately
Introduced Heterometallo-Supramolecular Polymer: Synthesis and
Solid-State Emission Switching by Electrochemical Redox. Chem.
Commun. 2013, 49 (46), 5256−2558. (g) Jurcek, O.; Bonakdarzadeh,
P.; Kalenius, E.; Linnanto, J. M.; Groessl, M.; Knochenmuss, R.;
Ihalainen, J. A.; Rissanen, K. Superchiral Pd3L6 Coordination Complex
and Its Reversible Structural Conversion into Pd3L3Cl6 Metallocycles.
Angew. Chem., Int. Ed. 2015, 54 (51), 15462−15467. (h) Liang, Y. P.;
He, Y. J.; Lee, Y. H.; Chan, Y. T. Self-Assembly of Triangular
Metallomacrocycles Using Unsymmetrical Bisterpyridine Ligands:
Isomer Differentiation via TWIM Mass Spectrometry. Dalton Trans.
2015, 44 (11), 5139−5145. (i) Wang, S.-Y.; Huang, J.-Y.; Liang, Y.-P.;
He, Y.-J.; Chen, Y.-S.; Zhan, Y.-Y.; Hiraoka, S.; Liu, Y.-H.; Peng, S.-M.;
Chan, Y.-T. Multicomponent Self-Assembly of Metallo-Supramolecu-
lar Macrocycles and Cagesthroughdynamic Heteroleptic Terpyridine
Complexation. Chem. - Eur. J. 2018, 24 (37), 9274−9284. (j) Ogata, D.;
Yuasa, J. Dynamic Open Coordination Cage from Nonsymmetrical
Imidazole-Pyridine Ditopic Ligands for Turn-On/Off Anion Binding.
Angew. Chem., Int. Ed. 2019, 58 (51), 18424−18428. (k) Sen, S. K.;
Natarajan, R. Influence of Conformational Change and Interligand
́
10499−10507. (e) Ramsay, W. J.; Szczypinski, F. T.; Weissman, H.;
Ronson, T. K.; Smulders, M. M. J.; Rybtchinski, B.; Nitschke, J. R.
Designed Enclosure Enables Guest Binding within the 4200 Å3 Cavity
of a Self-Assembled Cube. Angew. Chem., Int. Ed. 2015, 54 (19), 5636−
5640. (f) Ramsay, W. J.; Rizzuto, F. J.; Ronson, T. K.; Caprice, K.;
Nitschke, J. R. Subtle Ligand Modification Inverts Guest Binding
Hierarchy in MII L6 Supramolecular Cubes. J. Am. Chem. Soc. 2016, 138
8
(23), 7264−7267. (g) Mosquera, J.; Szyszko, B.; Ho, S. K. Y.; Nitschke,
J. R. Sequence-Selective Encapsulation and Protection of Long Peptides
by a Self-Assembled FeII L6 Cubic Cage. Nat. Commun. 2017, 8 (1),
8
14482. (h) Pilgrim, B. S.; Roberts, D. A.; Lohr, T. G.; Ronson, T. K.;
Nitschke, J. R. Signal Transduction in a Covalent Post-Assembly
Modification Cascade. Nat. Chem. 2017, 9 (12), 1276−1281.
(15) (a) Hiraoka, S.; Yamauchi, Y.; Arakane, R.; Shionoya, M.
Template-Directed Synthesis of a Covalent Organic Capsule Based on a
3 nm-Sized Metallocapsule. J. Am. Chem. Soc. 2009, 131 (33), 11646−
11647. (b) He, L.; Wang, S.-C.; Lin, L.-T.; Cai, J.-Y.; Li, L.; Tu, T.-H.;
Chan, Y.-T. Multicomponent Metallo-Supramolecular Nanocapsules
Assembled from Calix[4]Resorcinarene-Based Terpyridine Ligands. J.
Am. Chem. Soc. 2020, 142 (15), 7134−7144.
(16) (a) Lehn, J.-M.; Rigault, A.; Siegel, J.; Harrowfield, J.; Chevrier,
B.; Moras, D. Spontaneous Assembly of Double-Stranded Helicates
from Oligobipyridine Ligands and Copper(I) Cations: Structure of an
Inorganic Double Helix. Proc. Natl. Acad. Sci. U. S. A. 1987, 84 (9),
2565−2569. (b) Baxter, P.; Lehn, J.-M.; DeCian, A.; Fischer, J.
Multicomponent Self-Assembly: Spontaneous Formation of a Cylin-
drical Complex from Five Ligands and Six Metal Ions. Angew. Chem.,
Int. Ed. Engl. 1993, 32 (1), 69−72. (c) Hasenknopf, B.; Lehn, J.-M.;
Boumediene, N.; Dupont-Gervais, A.; Dorsselaer, A. V.; Kneisel, B.;
Fenske, D. Self-Assembly of Tetra- and Hexanuclear Circular Helicates.
J. Am. Chem. Soc. 1997, 119 (45), 10956−10962.
1232
https://dx.doi.org/10.1021/jacs.0c12508
J. Am. Chem. Soc. 2021, 143, 1224−1234

Journal of the American Chemical Society
pubs.acs.org/JACS
Article
Hydrogen Bonding in a Chiral Metal-Organic Cage. Inorg. Chem. 2019,
58 (11), 7180−7188. (l) Zhang, X.; Dong, X.; Lu, W.; Luo, D.; Zhu, X.-
W.; Li, X.; Zhou, X.-P.; Li, D. Fine-Tuning Apertures of Metal-Organic
Cages: Encapsulation of Carbon Dioxide in Solution and Solid State. J.
Am. Chem. Soc. 2019, 141 (29), 11621−11627. (m) Preston, D.; Inglis,
A. R.; Crowley, J. D.; Kruger, P. E. Self-Assembly and Cycling of a
Three-State PdxLy Metallosupramolecular System. Chem. - Asian J.
2019, 14 (19), 3404−3408. (n) Wang, W.; Zhou, Z.; Zhou, J.; Shi, B.;
Song, B.; Li, X.; Huang, F.; Stang, P. J. Self-Assembled Amphiphilic
Janus Double Metallacycle. Inorg. Chem. 2019, 58 (11), 7141−7145.
(o) Pu, L.-M.; Yu, M.; Zhang, Y.; Long, H.-T.; Xu, W.-B.; Dong, W.-K.
Tetranuclear Cobalt(II) and Nickel(II) Complexes with an Unsym-
metrical Salamo-Like Ligand: Structural Characterization, Hirshfeld
Analysis and Fluorescent Properties. Inorg. Chim. Acta 2020, 500,
119238. (p) Lewis, J. E. M.; Tarzia, A.; White, A. J. P.; Jelfs, K. E.
Conformational Control of Pd2L4 Assemblies with Unsymmetrical
Ligands. Chem. Sci. 2020, 11 (3), 677−683.
C.; Sprafke, J. K.; Kondratuk, D. V.; Rinfray, C.; Claridge, T. D. W.;
Saywell, A.; Blunt, M. O.; O’Shea, J. N.; Beton, P. H.; Malfois, M.;
Anderson, H. L. Vernier Templating and Synthesis of a 12-Porphyrin
Nano-Ring. Nature 2011, 469 (7328), 72−75. (c) May, R.; Jester, S.-S.;
̈
Hoger, S. A Giant Molecular Spoked Wheel. J. Am. Chem. Soc. 2014,
136 (48), 16732−16735. (d) Kondratuk, D. V.; Perdigao, L. M. A.;
̃
Esmail, A. M. S.; O’Shea, J. N.; Beton, P. H.; Anderson, H. L.
Supramolecular Nesting of Cyclic Polymers. Nat. Chem. 2015, 7 (4),
317−322. (e) Shang, J.; Wang, Y.; Chen, M.; Dai, J.; Zhou, X.; Kuttner,
J.; Hilt, G.; Shao, X.; Gottfried, J. M.; Wu, K. Assembling Molecular
Sierpinski Triangle Fractals. Nat. Chem. 2015, 7 (5), 389−93.
(f) Zhang, Y.; Kersell, H.; Stefak, R.; Echeverria, J.; Iancu, V.; Perera,
U. G. E.; Li, Y.; Deshpande, A.; Braun, K.-F.; Joachim, C.; Rapenne, G.;
Hla, S.-W. Simultaneous and Coordinated Rotational Switching of All
Molecular Rotors in a Network. Nat. Nanotechnol. 2016, 11 (8), 706−
712. (g) Gu, J.-Y.; Cai, Z.-F.; Wang, D.; Wan, L.-J. Single-Molecule
Imaging of Iron-Phthalocyanine-Catalyzed Oxygen Reduction Reac-
tion by in Situ Scanning Tunneling Microscopy. ACS Nano 2016, 10
(9), 8746−8750. (h) Mo, Y.; Chen, T.; Dai, J.; Wu, K.; Wang, D. On-
(21) (a) Suzuki, K.; Kawano, M.; Fujita, M. Solvato-Controlled
Assembly of Pd3L6 and Pd4L8 Coordination ″Boxes″. Angew. Chem., Int.
Ed. 2007, 46 (16), 2819−2822. (b) Suzuki, K.; Tominaga, M.; Kawano,
M.; Fujita, M. Self-Assembly of an M6L12 Coordination Cube. Chem.
Commun. 2009, 13, 1638−1640. (c) Zheng, Y.-R.; Zhao, Z.; Wang, M.;
Ghosh, K.; Pollock, J. B.; Cook, T. R.; Stang, P. J. A Facile Approach
toward Multicomponent Supramolecular Structures: Selective Self-
Assembly via Charge Separation. J. Am. Chem. Soc. 2010, 132 (47),
16873−16882. (d) Inokuma, Y.; Arai, T.; Fujita, M. Networked
Molecular Cages as Crystalline Sponges for Fullerenes and Other
Guests. Nat. Chem. 2010, 2 (9), 780−783. (e) Clever, G. H.;
Kawamura, W.; Tashiro, S.; Shiro, M.; Shionoya, M. Stacked Platinum
Complexes of the Magnus’ Salt Type inside a Coordination Cage.
Angew. Chem., Int. Ed. 2012, 51 (11), 2606−2609. (f) Harris, K.; Sun,
Q.-F.; Sato, S.; Fujita, M. M12L24 Spheres with Endo and Exo
Coordination Sites: Scaffolds for Non-Covalent Functionalization. J.
Am. Chem. Soc. 2013, 135 (34), 12497−12499. (g) Fu, J.-H.; Lee, Y.-H.;
He, Y.-J.; Chan, Y.-T. Facile Self-Assembly of Metallo-Supramolecular
Ring-in-Ring and Spiderweb Structures Using Multivalent Terpyridine
Ligands. Angew. Chem., Int. Ed. 2015, 54 (21), 6231−6235. (h) Sun, B.;
Wang, M.; Lou, Z.; Huang, M.; Xu, C.; Li, X.; Chen, L.-J.; Yu, Y.; Davis,
G. L.; Xu, B.; Yang, H.-B.; Li, X. From Ring-in-Ring to Sphere-in-
Sphere: Self-Assembly of Discrete 2D and 3D Architectures with
Increasing Stability. J. Am. Chem. Soc. 2015, 137 (4), 1556−1564.
(i) Roberts, D. A.; Pilgrim, B. S.; Cooper, J. D.; Ronson, T. K.; Zarra, S.;
́
Surface Synthesis of Highly Ordered Covalent Sierpinski Triangle
Fractals. J. Am. Chem. Soc. 2019, 141 (29), 11378−11382. (i) Wang, X.;
Cai, Z.-F.; Wang, Y.-Q.; Feng, Y.-C.; Yan, H.-J.; Wang, D.; Wan, L.-J. In
Situ Scanning Tunneling Microscopy of Cobalt-Phthalocyanine-
Catalyzed CO2 Reduction Reaction. Angew. Chem., Int. Ed. 2020, 59
(37), 16098−16103. (j) Zhang, Z.; Li, Y.; Song, B.; Zhang, Y.; Jiang, X.;
Wang, M.; Tumbleson, R.; Liu, C.; Wang, P.; Hao, X.-Q.; Rojas, T.;
Ngo, A. T.; Sessler, J. L.; Newkome, G. R.; Hla, S.-W.; Li, X. Intra- and
Intermolecular Self-Assembly of a 20-nm-Wide Supramolecular
Hexagonal Grid. Nat. Chem. 2020, 12 (5), 468−474. (k) Wang, L.;
Song, B.; Li, Y.; Gong, L.; Jiang, X.; Wang, M.; Lu, S.; Hao, X.-Q.; Xia,
Z.; Zhang, Y.; Hla, S.-W.; Li, X. Self-Assembly of Metallo-Supra-
molecules under Kinetic or Thermodynamic Control: Characterization
of Positional Isomers Using Scanning Tunneling Spectroscopy. J. Am.
Chem. Soc. 2020, 142 (21), 9809−9817.
(23) (a) Newkome, G. R.; Wang, P.; Moorefield, C. N.; Cho, T. J.;
Mohapatra, P. P.; Li, S.; Hwang, S.-H.; Lukoyanova, O.; Echegoyen, L.;
Palagallo, J. A.; Iancu, V.; Hla, S.-W. Nanoassembly of a Fractal
Polymer: A Molecular ‘‘Sierpinski Hexagonal Gasket’’. Science 2006,
312 (5781), 1782−1785. (b) Zhang, Z.; Wang, H.; Wang, X.; Li, Y.;
Song, B.; Bolarinwa, O.; Reese, R. A.; Zhang, T.; Wang, X.-Q.; Cai, J.;
Xu, B.; Wang, M.; Liu, C.; Yang, H.-B.; Li, X. Supersnowflakes: Stepwise
Self-Assembly and Dynamic Exchange of Rhombus Star-Shaped
Supramolecules. J. Am. Chem. Soc. 2017, 139 (24), 8174−8185.
(c) Song, B.; Kandapal, S.; Gu, J.; Zhang, K.; Reese, A.; Ying, Y.; Wang,
L.; Wang, H.; Li, Y.; Wang, M.; Lu, S.; Hao, X.-Q.; Li, X.; Xu, B.; Li, X.
Self-Assembly of Polycyclic Supramolecules Using Linear Metal-
Organic Ligands. Nat. Commun. 2018, 9 (1), 4575. (d) Wang, L.;
Liu, R.; Gu, J.; Song, B.; Wang, H.; Jiang, X.; Zhang, K.; Han, X.; Hao,
X.-Q.; Bai, S.; Wang, M.; Li, X.; Xu, B.; Li, X. Self-Assembly of
Supramolecular Fractals from Generation 1 to 5. J. Am. Chem. Soc.
2018, 140 (43), 14087−14096. (e) Wang, H.; Li, Y.; Yu, H.; Song, B.;
Lu, S.; Hao, X.-Q.; Zhang, Y.; Wang, M.; Hla, S.-W.; Li, X. Combining
Synthesis and Self-Assembly in One Pot to Construct Complex 2D
Metallo-Supramolecules Using Terpyridine and Pyrylium Salts. J. Am.
Chem. Soc. 2019, 141 (33), 13187−13195. (f) Li, Y.; Huo, G.-F.; Liu,
B.; Song, B.; Zhang, Y.; Qian, X.; Wang, H.; Yin, G.-Q.; Filosa, A.; Sun,
W.; Hla, S. W.; Yang, H.-B.; Li, X. Giant Concentric Metal-
losupramolecule with Aggregation-Induced Phosphorescent Emission.
J. Am. Chem. Soc. 2020, 142 (34), 14638−14648.
Nitschke, J. R. Post-Assembly Modification of Tetrazine-Edged FeII L6
4
Tetrahedra. J. Am. Chem. Soc. 2015, 137 (32), 10068−10071.
(j) Castilla, A. M.; Ronson, T. K.; Nitschke, J. R. Sequence-Dependent
Guest Release Triggered by Orthogonal Chemical Signals. J. Am. Chem.
Soc. 2016, 138 (7), 2342−2351. (k) Rizzuto, F. J.; Wu, W.-Y.; Ronson,
T. K.; Nitschke, J. R. Peripheral Templation Generates an MII L4 Guest-
6
Binding Capsule. Angew. Chem., Int. Ed. 2016, 55 (28), 7958−7962.
(l) Wang, S.-Y.; Fu, J.-H.; Liang, Y.-P.; He, Y.-J.; Chen, Y.-S.; Chan, Y.-
T. Metallo-Supramolecular Self-Assembly of a Multicomponent
Ditrigon Based on Complementary Terpyridine Ligand Pairing. J.
Am. Chem. Soc. 2016, 138 (11), 3651−3654. (m) Rizzuto, F. J.;
Nitschke, J. R. Stereochemical Plasticity Modulates Cooperative
Binding in a CoII12L6 Cuboctahedron. Nat. Chem. 2017, 9 (9), 903−
908. (n) Rizzuto, F. J.; Wood, D. M.; Ronson, T. K.; Nitschke, J. R.
Tuning the Redox Properties of Fullerene Clusters within a Metal-
Organic Capsule. J. Am. Chem. Soc. 2017, 139 (32), 11008−11011.
(o) Yin, G.-Q.; Wang, H.; Wang, X.-Q.; Song, B.; Chen, L.-J.; Wang, L.;
Hao, X.-Q.; Yang, H.-B.; Li, X. Self-Assembly of Emissive Supra-
molecular Rosettes with Increasing Complexity Using Multitopic
Terpyridine Ligands. Nat. Commun. 2018, 9 (1), 567. (p) Carpenter, J.
P.; McTernan, C. T.; Ronson, T. K.; Nitschke, J. R. Anion Pairs
Template a Trigonal Prism with Disilver Vertices. J. Am. Chem. Soc.
2019, 141 (29), 11409−11413.
(24) Chan, Y.-T.; Li, X.; Yu, J.; Carri, G. A.; Moorefield, C. N.;
Newkome, G. R.; Wesdemiotis, C. Design, Synthesis, and Traveling
Wave Ion Mobility Mass Spectrometry Characterization of Iron(II)-
and Ruthenium(II)-Terpyridine Metallomacrocycles. J. Am. Chem. Soc.
2011, 133 (31), 11967−11976.
(25) (a) Kanu, A. B.; Dwivedi, P.; Tam, M.; Matz, L.; Hill, H. H., Jr.
Ion Mobility-Mass Spectrometry. J. Mass Spectrom. 2008, 43 (1), 1−22.
(b) Chan, Y.-T.; Li, X.; Soler, M.; Wang, J.-L.; Wesdemiotis, C.;
Newkome, G. R. Self-Assembly and Traveling Wave Ion Mobility Mass
Spectrometry Analysis of Hexacadmium Macrocycles. J. Am. Chem. Soc.
(22) (a) De Feyter, S.; Grim, P. C. M.; Esch, J. V.; Kellogg, R. M.;
Feringa, B. L.; Schryver, F. C. D. Nontrivial Differentiation between
Two Identical Functionalities within the Same Molecule Studied by
STM. J. Phys. Chem. B 1998, 102 (45), 8981−8987. (b) O’Sullivan, M.
1233
https://dx.doi.org/10.1021/jacs.0c12508
J. Am. Chem. Soc. 2021, 143, 1224−1234

Journal of the American Chemical Society
pubs.acs.org/JACS
Article
2009, 131 (45), 16395−16397. (c) Brocker, E. R.; Anderson, S. E.;
Northrop, B. H.; Stang, P. J.; Bowers, M. T. Structures of
Metallosupramolecular Coordination Assemblies Can Be Obtained
by Ion Mobility Spectrometry-Mass Spectrometry. J. Am. Chem. Soc.
2010, 132 (38), 13486−13494. (d) Ujma, J.; De Cecco, M.; Chepelin,
O.; Levene, H.; Moffat, C.; Pike, S. J.; Lusby, P. J.; Barran, P. E. Shapes
of Supramolecular Cages by Ion Mobility Mass Spectrometry. Chem.
Commun. 2012, 48 (37), 4423−4425.
(26) Li, Z.; Li, Y.; Zhao, Y.; Wang, H.; Zhang, Y.; Song, B.; Li, X.; Lu,
S.; Hao, X.-Q.; Hla, S.-W.; Tu, Y.; Li, X. Synthesis of Metallopolymers
and Direct Visualization of the Single Polymer Chain. J. Am. Chem. Soc.
2020, 142 (13), 6196−6205.
(27) (a) Chen, L.-J.; Zhao, G.-Z.; Jiang, B.; Sun, B.; Wang, M.; Xu, L.;
He, J.; Abliz, Z.; Tan, H.; Li, X.; Yang, H.-B. Smart Stimuli-Responsive
Spherical Nanostructures Constructed from Supramolecular Metal-
lodendrimers via Hierarchical Self-Assembly. J. Am. Chem. Soc. 2014,
136 (16), 5993−6001. (b) Ludlow, J. M.; Saunders, M. J.; Huang, M.;
Guo, Z.; Moorefield, C. N.; Cheng, S. Z. D.; Wesdemiotis, C.;
Newkome, G. R. Amphiphilic [Tpy-MII-Tpy] Metallotriangles: Syn-
thesis, Characterisation and Hierarchical Ordering. Supramol. Chem.
2017, 29 (1), 69−79.
1234
https://dx.doi.org/10.1021/jacs.0c12508
J. Am. Chem. Soc. 2021, 143, 1224−1234