Over the past decades, molecular knots and links have captivated the chemical community due to their promising mimicry properties in molecular machines and biomolecules and are being realized with ...increasing frequency with small molecules. Herein, we describe how to utilize stacking interactions and hydrogen-bonding patterns to form trefoil knots, figure-eight knots and 2catenanes. A transformation can occur between the unique trefoil knot and its isomeric boat-shaped tetranuclear macrocycle by the complementary concentration effect. Remarkably, the realization and authentication of the molecular figure-eight knot with four crossings fills the blank about 4
knot in knot tables. The 2catenane topology is obtained because the selective naphthalenediimide (NDI)-based ligand, which can engender favorable aromatic donor-acceptor π interactions due to its planar, electron-deficient aromatic surface. The stacking interactions and hydrogen-bond interactions play important roles in these self-assembly processes. The advantages provide an avenue for the generation of structurally and topologically complex supramolecular architectures.
Intricately interwoven topologies are continually being synthesized and are ultimately equally versatile and significant at the nanoscale level; however, reports concerning ravel structures, which ...are highly entwined new topological species, are extremely rare and fraught with tremendous synthesis challenges. To solve the synthesis problem, a tetrapodontic pyridine ligand L1 with two types of olefinic bond units and two Cp*M‐based building blocks (E1, M=Rh; E2, M=Ir) featuring large conjugated planes was prepared to perform the self‐assembly. Two unprecedented 5+10 icosanuclear molecular 4‐ravels containing four crossings were obtained by parallel‐displaced π⋅⋅⋅π interactions in a single‐step strategy. Remarkably, reversible structural transformations between the 4‐ravel and the corresponding metallocage could be realized by concentration changes and solvent‐ and guest‐induced effects. X‐ray crystallographic data and NMR spectroscopy provide full confirmation of these phenomena.
Two unprecedented 5+10 icosanuclear molecular 4‐ravels containing four crossings have been generated using a single‐step strategy. This topology is achieved by utilizing parallel‐displaced π⋅⋅⋅π interactions with carefully selected naphthoquinoyl Cp*M building blocks and X‐shaped pyridyl ligands.
This review mainly focuses on introducing the different assembled strategies of the heterometallic-organic frameworks (HMOFs), and highlights the influence of the synergistic effect on their enhanced ...physical and chemical performances.
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•The recent advances are carefully introduced for the functional heterometallic-organic frameworks (HMOFs) in detail.•The assembled strategies are presented to isolate the functional HMOFs, such as such as one-pot synthesis, post-synthetic modification, ion exchange strategy, and grinding method, etc.•This work shows the enhanced performances of HMOFs via the synergistic effect for the adsorption, catalysis, magnetism, and fluorescence, etc.•The conclusion and outlook are given for the future development of HMOF materials.•This review will supply some useful guides for the preparation of new HMOF materials for wide applications in the whole energy landscape.
Metal-organic frameworks (MOFs) have different structures and various intrinsic properties, such as large specific surface area, flexible and adjustable structural configurations, coordinately-unsaturated metal center, etc., which facilitate the rapid development and wide application of coordination chemistry, over the past decades, including gas adsorption, catalysis, and magnetism. Although the metals in various regions of the periodic table have been explored to build different monometallic MOFs, the researches about functional heterometallic-organic framework (HMOF) materials have not been particularly in-depth. Compared with monometallic MOFs, some special positions are occupied by the heterogeneous metals in one HMOF, which will result in interesting network topologies, and the excellent synergistic effect between the different metal ions will make the physical and chemical properties to be effectively enhanced. This review mainly focuses on introducing the latest progresses of HMOFs, including the various synthesis strategies, applications and outlooks, which may provide some useful guidance for the preparation of novel HMOF materials and make them widely used in the whole energy landscape.
Molecular figure-eight knot (notation: 41) is extremely rare and presents great synthetic challenge due to its essentially complicated entanglement. To solve this synthetic problem, a quadruple ...stacking strategy was developed. Herein, we report the efficient self-assembly of figure-eight knots induced by quadruple stacking interactions, through the combination of four carefully selected naphthalenediimide (NDI)-based pyridyl ligands and Cp*Rh building blocks bearing large conjugated planes in a single-step strategy. Notably, slight size adjustment of the Cp*Rh units was found to affect the stability of the figure-eight knots in methanol. Additionally, reversible structural transformations between these figure-eight knots and corresponding metallorectangles could be achieved by concentration changes and solvent- and guest-induced effects. X-ray crystallographic data and NMR spectroscopy provide full confirmation of these phenomena.
Due to their fascinating topological structures and application prospects, coordination supramolecular complexes have continuously been studied by scientists. However, the controlled construction and ...property study of organometallic handcuffs remains a significant and challenging research subject in the area of supramolecular chemistry. Hence, a series of tetranuclear organometallic and heterometallic handcuffs bearing different size and metal types were rationally designed and successfully synthesized by utilizing a quadridentate pyridyl ligand (tetra-(3-pyridylphenyl)ethylene) based on three Cp*Rh (Cp* = η5-C5Me5) fragments bearing specific longitudinal dimensions and conjugated planes. These results were determined with single-crystal X-ray diffraction analysis technology, ESI-MS NMR spectroscopy, etc. Importantly, the photoquenching effect of Cp* groups and the discrepancy of intermolecular π–π stacking interactions between building block and half-sandwich fragments promote markedly different photothermal conversion results. These results will further push the synthesis of topological structures and the development of photothermal conversion materials.
Two novel compounds, a molecular trefoil knot and a Solomon link, were constructed successfully through the cooperation of multiple π-π stacking interactions. A reversible transformation between the ...trefoil knot and the corresponding 2 + 2 macrocycle could be achieved by solvent- and guest-induced effects. However, the Solomon link maintains its stability in different concentrations, solvents and guest molecules. Single-crystal X-ray crystallographic data, NMR spectroscopic experiments and ESI-MS support the synthesis and structural assignments. These synthesis methods open the door to the further development of smart materials, which will push the advancement of rational design of biomaterials.
Although the selective synthesis of complicated supramolecular architectures has seen significant progress in recent years, the exploration of the properties of these complexes remains a fascinating ...challenge. Herein, a series of new supramolecular topologies, metalla2catenanes and Borromean ring assemblies, were constructed based on appropriate Cp*Rh building blocks and two rigid alkynyl pyridine ligands (
L1
,
L2
)
via
coordination-driven self-assembly. Interestingly, minor differences between the two rigid alkynyl pyridine ligands with/without organic substituents led to products with dramatically different topologies. Careful structural analysis showed that π-π stacking interactions play a crucial role in stabilizing these 2catenanes and Borromean ring assemblies, while also promoting nonradiative transitions and triggering photothermal conversion in both the solution and the solid states. These results were showcased through comparative studies of the NIR photothermal conversion efficiencies of the Borromean ring assemblies, 2catenanes and metallarectangles, which exhibited a wide range of photothermal conversion efficiencies (12.64-72.21%). The influence of the different Cp*Rh building blocks on the NIR photothermal conversion efficiencies of their assemblies was investigated. Good photothermal conversion properties of the assemblies were also found in the solid state. This study provides a new strategy to construct valuable half-sandwich-based NIR photothermal conversion materials while also providing promising candidates for the further development of materials science.
The selective synthesis of three kinds of supermolecular topologies, molecular Borromean ring, 2catenane and metallarectangle based on two alkynyl ligands is presented. Remarkably, the NIR photothermal conversion efficiency was found to improve as the π-π stacking increases.
Herein, one interdigitated molecular and two metallarectangles were realized successfully using two rigid bidentate ligands (L1, L2) and two building blocks (E1, E2) via coordination-driven ...self-assembly strategy. Interestingly, a novel interdigitated structure has been successfully formed through triple π-π stacking interactions, different from the previously reported interlocked 2catenanes. Based on the π-π stacking interaction, nonradiative transitions were promoted and obvious photothermal transitions effect was triggered in solution and solid states. In addition, it is found that the interdigitated structure has a decent photothermal conversion efficiency of about 12% in solution state. This study provides open up new ideas for our future development of near-infrared photothermal conversion materials.
A series of discrete metallarectangles and an interdigitated molecule were synthesized by coordination-driven self-assembly. These topologies were unambiguously confirmed by NMR spectroscopy, ESI-MS, IR spectroscopy as well as X-ray crystallography. In addition, triple π-π stacking interactions were found in the interdigitated structure, which results in the capability of photothermal conversion. Display omitted
•One interdigitated molecular and two metallarectangles were realized successfully using two rigid bidentate ligands and two building blocks via coordination-driven self-assembly strategy.•The interdigitated structure was constructed through triple π-π stacking interactions, different from the previously reported interlocked 2catenanes, which result in nonradiative transitions and trigger photothermal conversion in both the solution and the solid states.•The photothermal conversion study exhibits a good photothermal conversion efficiency (12%) for the interdigitated structure at 660 nm in the solution state. This study provides open up new ideas for our future development of near-infrared photothermal conversion materials.
Herein, a new Zn-MOF material, Zn(
)(
),
, was built successfully through a one-pot solvothermal method. The 3D MOF structure was determined by Single X-ray diffraction analysis, IR, and elemental ...analysis. A series of PXRD tests of
after being immersed in different solvents and pH solutions demonstrated the good stability of
. Interestingly, this material displayed high catalytic activity for the visible-light-driven hydrogen generation under the illumination of white LED in pure water or a mixture of DMF and H
O without additional photosensitizers and cocatalysts. Besides, the studies also showed that the catalytic activity changed constantly as well as the solvent ratio adjustment of DMF and H
O from 4:6 to 2:8. Additionally, the catalytic activity reached the best value (743 μmol g
h
) when the solvent ratio was 4:6. The heterogeneous nature and recyclability of the MOF catalyst, as well as several factors that affect the catalytic activity, were investigated and described in detail. Moreover, the photocatalytic mechanism for the hydrogen generation of
was also proposed based on the fluorescence spectra and UV-vis absorption.
A new metal–organic framework (MOF), Co2(L)2(azpy)n (compound 1, H2L = 5-(pyridin-4-ylmethoxy)-isophthalic acid, azpy = 4,4′-azopyridine), was synthesized by a solvothermal method and further ...characterized by elemental analysis, IR spectra, thermogravimetric analysis, single-crystal and powder X-ray diffraction. The X-ray single-crystal diffraction analysis for compound 1 indicated that two cis L22− ligands connected to two cobalt atoms resulted in a macrocycle structure. Through a series of adsorption tests, we found that compound 1 exhibited a high capacity of CO2, and the adsorption capacity could reach 30.04 cm3/g. More interestingly, under 273 K conditions, the adsorption of CO2 was 41.33 cm3/g. In addition, when the Co-MOF was irradiated by a 730 nm laser, rapid temperature increases for compound 1 were observed (temperature variation in 169 s: 26.6 °C), showing an obvious photothermal conversion performance. The photothermal conversion efficiency reached 20.3%, which might be due to the fact that the parallel arrangement of azo units inhibited non-radiative transition and promoted photothermal conversion. The study provides an efficient strategy for designing MOFs for the adsorption of CO2 and with good photothermal conversion performance.
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