Triply interlocked [2]catenane complexes featuring two identical, mechanically interlocked units are extraordinarily rare chemical compounds, whose properties and applications remain open to detailed studies. Herein, we introduce the rational design of a new ligand precursor, L1, suitable for the synthesis of six triply interlocked [2]catenanes by coordination-driven self-assembly. The interlocked compounds can be reversibly converted into the corresponding simple triangular prism metallacage by addition of H2O or DMF solvents to their CH3OH solutions, thereby demonstrating the importance of π⋅⋅⋅π stacking and hydrogen bonding interactions in the formation of triply interlocked [2]catenanes. Moreover, extensive studies have been conducted to assess the remarkable photothermal conversion performance. Complex 6 a, exhibiting outstanding photothermal conversion performance (conversion efficiency in solution : 31.82 %), is used to prepare novel photoresponsive elastomer in combination with thermally activated liquid crystal elastomer. The resultant material displays robust response to near-infrared (NIR) laser and the capability of completely reforming the shape and reversible actuation, paving the way for the application of half-sandwich organometallic units in photo-responsive smart materials.

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.

Fluorescence nanosensors based on functional nucleic acids have been explored as a powerful sensing platform for disease-relevant miRNAs. This work developed a new hybrid nanosensor (Zr-B) through coordination-driven self-assembly of Zr ions and beacons. The prepared nanosensor exhibited high loading efficiency of beacons and could achieve sensitive and specific detection for miRNAs. The hybrid nanosensor could transfer beacons into living cells efficiently and maintain high stability and biocompatibility in the biological environment, achieving effective miRNA fluorescence imaging in living cells. Therefore, the resultant nanosensor holds potential for applications in disease diagnostics.

Radiotherapy is a mainstream modality for breast cancer treatment that employs ionizing radiation (IR) to damage tumor cell DNA and elevate ROS stress, which demonstrates multiple clinically-favorable advantages including localized treatment and low invasiveness. However, breast cancer cells may activate the p53-mediated cell cycle regulation in response to radiotherapy to repair IR-induced cellular damage and facilitate post-treatment survival. F-Box and WD Repeat Domain Containing 7 (FBXW7) is a promoter of p53 degradation and critical nexus of cell proliferation and survival events. Herein, we engineered a cooperative radio-ferroptosis-stimulatory nanomedicine through coordination-driven self-assembly between ferroptosis-inducing Fe2+ ions and FBXW7-inhibiting DNAzymes and further modification of tumor-targeting dopamine-modified hyaluronic acid (HA). The nanoassembly could be selectively internalized by breast cancer cells and disintegrated in lysosomes to release the therapeutic payload. DNAzyme readily abolishes FBXW7 expression and stabilizes phosphorylated p53 to cause irreversible G2 phase arrest for amplifying post-IR tumor cell apoptosis. Meanwhile, the p53 stabilization also inhibits the SLC7A11-cystine-GSH axis, which combines with the IR-upregulated ROS levels to amplify Fe2+-mediated ferroptotic damage. The DNAzyme-Fe-HA nanoassembly could thus systematically boost the tumor cell damaging effects of IR, presenting a simple and effective approach to augment the response of breast cancer to radiotherapy. STATEMENT OF SIGNIFICANCE: To overcome the intrinsic radioresistance in breast cancer, we prepared co-assembly of Fe2+ and FBXW7-targeted DNAzymes and modified surface with dopamine conjugated hyaluronic acid (HA), which enabled tumor-specific FBXW7-targeted gene therapy and ferroptosis therapy in IR-treated breast cancers. The nanoassembly could be activated in acidic condition to release the therapeutic contents. Specifically, the DNAzymes could selectively degrade FBXW7 mRNA in breast cancer cells to simultaneously induce accumulation of p53 and retardation of NHEJ repair, eventually inducing irreversible cell cycle arrest to promote apoptosis. The p53 stabilization would also inhibit the SLC7A11/GSH/GPX4 axis to enhance Fe2+ mediated ferroptosis. These merits could act in a cooperative manner to induce pronounced tumor inhibitory effect, offering new approaches for tumor radiosensitization in the clinics.

Reported here is the synthesis of a macrocycle with equatorial coordination sites for the construction of self-assembled metallacages. The macrocycle is prepared via a post-modification on the equator of biphen[n]arene. Utilizing this macrocycle as a ligand, three prismatic cages and one octahedral cage were synthesized by regulating the geometric structures and coordination number of metal acceptors. The multi-cavity configuration of prismatic cage was revealed by single-crystal structure. We prove that a macrocycle with equatorial coordination sites can be an excellent building block for synthesizing structure-diverse metallacages. Our results provide a typical example and a general method for the design and synthesis of metallacages.

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.

A series of Cp* Rh-based discrete architectures was constructed by selecting four ether bipyridyl ligands and three half-sandwich rhodium(III) bimetallic construction units, respectively. This study demonstrates a strategy for making the transition from a binuclear D-shaped ring to a tetranuclear [2]catenane by adjusting the length of bipyridyl ligands. In addition, changing the position on the naphthyl group of the bipyridyl ligand from 2,6- to 1,5-position substitution can realize the selective synthesis of [2]catenane and Borromean rings under similar conditions. The above-mentioned constructions have been determined via X-ray crystallographic analysis, detailed NMR techniques, electrospray ionization-time-of-flight/mass spectrometry analysis, and elemental analysis.

Chiral self-sorting during the formation of cage-like molecules continues to fascinate and advance our understanding of the phenomenon in general. Herein, we report the chiral self-sorting in the Pd6 L12 -type metal-organic cages. When a racemic mixture of axially chiral bis-pyridyl ligands undergo coordination-driven self-assembly with Pd(II) ions to form Pd6 L12 -type cages, the system has the option of chiral self-sorting to afford any of at least 70 pairs of (one homochiral and 69 heterochiral) enantiomers and 5 meso isomers or a statistical mixture of everything. However, the system resulted in diastereoselective self-assembly through a high-fidelity chiral social self-sorting to form a racemic mixture of D3 symmetric heterochiral [Pd6 (L6R/6S )12 ]12+ /[Pd6 (L6S/6R )12 ]12+ cages.

Nanozymes and amorphous nanomaterials attract great attention owing to their extraordinary properties. However, the requirements for special synthesis conditions become the bottleneck of their development. Herein, a new strategy involving the DNA-based coordination-driven self-assembly is reported for the synthesis of a novel amorphous/crystalline hetero-phase nanozyme (Fe-DNA). For the synthesis of both nanozymes and amorphous materials, this strategy is simple and controllable, avoiding the traditionally employed harsh conditions. Benefitting from the amorphous structure and the superior physicochemical properties, the synthesized Fe-DNA nanozyme is subsequently found to exhibit a smaller Michaelis constant value for hydrogen peroxide (H2 O2 ) (0.81 mm) than that of horseradish peroxidase (HRP) (3.70 mm), demonstrating the stronger affinity of the Fe-DNA nanozyme toward H2 O2 . The Fe-DNA nanozyme also shows significant peroxidase-like activity but only negligible oxidase-like activity, a characteristic which releases the corresponding assay system from oxygen interference, thereby improving the performance of the nanozyme-based sensing platform. In addition, compared with other nanozymes, the novel Fe-DNA nanozyme is degradable via phosphate; thus, mitigating potential environmental threat. This work provides novel amorphous/crystalline hetero-phase nanozymes and opens a new avenue for the design of amorphous nanomaterials and nanozymes.

When a racemic mixture of chiral building blocks self-assembles to form discrete molecular or supramolecular cages, the system can adopt either social or narcissistic chiral self-sorting. However, control over such chiral self-sorting is hard to achieve with a desired choice of outcome. Herein, we report anion templated high-fidelity chiral self-sorting during the coordination-driven self-assembly of [Pd2 L4 ] metal-organic cages, with a racemic mixture of an axially chiral ligand. Upon varying the counter-anions, the outcome of the choice of chiral self-sorting, whether social or narcissistic, leading to kinetically favored heterochiral or thermodynamically favored homochiral cages, can be controlled through specific anion encapsulation. Non-encapsulating anion afforded a mixture of all possible diastereomers. Anion exchange enabled structural transformations between the diastereomers and the conversion of the mixture of diastereomers into homochiral diastereomers.