Stepwise and Controllable Synthesis of Mesoporous Heterotrimetallic Catalysts Based on Predesigned Al4 Ln4 Metallocycles.

The motivation for making heterometallic compounds stemmed from their emergent synergistic properties and enhanced capabilities for applications. However, the atomically precisely controlled synthesis of heterometallic compounds remains a daunting challenge of the complications that arise when applying several metals and linkers. Herein, a stepwise and controlled method is reported for the accurate addition of second and third metals to homometallic aluminum macrocycles based on the synergistic coordination and hard-soft acid-base theory. These heterometallic compounds showed a good Lewis acid catalytic effect, and the addition of hetero-metals significantly improved the catalytic effect and rate, among that the conversion rate of compound AlOC-133 reached 99.9% within half an hour. This method combines both the independent controllability of stepwise assembly with the universality of one-step methods. Based on the large family of clusters, the establishment of this method paves the way for the controllable and customized molecular-level synthesis of heterometallic materials and creates materials customized for preferential application.

Dynamic Stereochemistry of M8 Pd6 Supramolecular Cages Based on Metal-Center Lability for Differential Chiral Induction, Resolution, and Recognition.

A series of isostructural supramolecular cages with a rhombic dodecahedron shape have been assembled with distinct metal-coordination lability (M8 Pd6 -MOC-16, M=Ru2+ , Fe2+ , Ni2+ , Zn2+ ). The chirality transfer between metal centers generally imposes homochirality on individual cages to enable solvent-dependent spontaneous resolution of Δ8 /Λ8 -M8 Pd6 enantiomers; however, their distinguishable stereochemical dynamics manifests differential chiral phenomena governed by the cage stability following the order Ru8 Pd6 >Ni8 Pd6 >Fe8 Pd6 >Zn8 Pd6 . The highly labile Zn centers endow the Zn8 Pd6 cage with conformational flexibility and deformation, enabling intrigue chiral-Δ8 /Λ8 -Zn8 Pd6 to meso-Δ4 Λ4 -Zn8 Pd6 transition induced by anions. The cage stabilization effect differs from inert Ru2+ , metastable Fe2+ /Ni2+ , and labile Zn2+ , resulting in different chiral-guest induction. Strikingly, solvent-mediated host-guest interactions have been revealed for Δ8 /Λ8 -(Ru/Ni/Fe)8 Pd6 cages to discriminate the chiral recognition of the guests with opposite chirality. These results demonstrate a versatile procedure to control the stereochemistry of metal-organic cages based on the dynamic metal centers, thus providing guidance to maneuver cage chirality at a supramolecular level by virtue of the solvent, anion, and guest to benefit practical applications.

Dynamic Metallosupramolecular Cages Containing 12 Adaptable Pockets for High-Order Guest Binding Beyond Biomimicry.

Molecular recognition lies at the heart of biological functions, which inspires lasting research in artificial host syntheses to mimic biomolecules that can recognize, process, and transport molecules with the highest level of complexity; nonetheless, the design principle and quantifying methodology of artificial hosts for multiple guests (≥4) remain a formidable task. Herein, we report two rhombic dodecahedral cages [(Zn/Fe)8Pd6-MOC-16], which embrace 12 adaptive pockets for multiguest binding with distinct conformational dynamics inherent in metal-center lability and are able to capture 4-24 guests to manifest a surprising complexity of binding scenarios. The exceptional high-order and hierarchical encapsulation phenomena suggest a wide host-guest dynamic-fit, enabling conformational adjustment and adaptation beyond the duality of induced-fit and conformational selection in protein interactions. A critical inspection of the host-guest binding events in solution has been performed by NMR and ESI-MS spectra, highlighting the importance of acquiring a reliable binding repertoire from different techniques and the uncertainty of quantifying the binding affinities of multiplying guests by an oversimplified method.

Heterometallic Al6Zn12 nano-plate with π-conjugated ligand: synthesis and nonlinear absorption properties.

Presented herein is the synthesis, structure, and optical properties of the aluminum(III)-zinc(II) heterometallic compound AlOC-57. This compound was found to form a large unit cell (approximately sixteen thousand atoms) and a three-shell nano-plate structure. Based on the Z-scan patterns, the third-order nonlinear optical response of the heterometallic nano-plate was mainly attributed to its nonlinear absorption (reverse saturable absorption).

Designable Assembly of Aluminum Molecular Rings for Sequential Confinement of Iodine Molecules.

Although numerous adsorbent materials have been reported for the capture of radioactive iodine, there is still demand for new absorbents that are economically viable and can be prepared by reliable synthetic protocols. Herein, we report a coordination-driven self-assembly strategy towards adsorbents for the sequential confinement of iodine molecules. These adsorbents are versatile heterometallic frameworks constructed from aluminum molecular rings of varying size, flexible copper ions, and conjugated carboxylate ligands. Additionally, these materials can quickly remove iodine from cyclohexane solutions with a high removal rate (98.8 %) and considerable loading capacity (555.06 mg g-1 ). These heterometallic frameworks provided distinct pore sizes and binding sites for iodine molecules, and the sequential confinement of iodine molecules was supported by crystallographic data. This work not only sets up a bridge between molecular rings and infinite porous networks but also reveals molecular details for the underlying host-guest binding interactions at crystallographic resolution.

Designable Aluminum Molecular Rings: Ring Expansion and Ligand Functionalization.

Presented herein are the AlIII molecular ring architectures from 8-ring to 16-ring. Although there are numerous reported cyclic coordination compounds based on transition metals, gallium, or lanthanides, the Al versions are less developed due to the fast hydrolysis nature of Al3+ ion. With the assistant of monohydric alcohols, a series of atomic precisely Al molecular rings based on benzoates are synthesized. The ring expansion of these Al-rings from 8-ring to 16-ring is related to the monohydric alcohol structure-directing agents. Moreover, the organic ligands on the Al-rings can be modified by using various benzoate derivatives, which lead to tunable surface properties of the Al-rings from hydrophilicity to ultra-hydrophobicity. Importantly, 4-aminobenzoic acid bridged 16-ring is soluble in organic solvents and exhibits high solution stability revealed by mass spectroscopy. Ligand substitution also can be performed between these Al-rings, which reveal controllable ligand functionalization of these Al-rings.

Celecoxib inhibits insulin-like growth factor 1 induced growth and invasion in non-small cell lung cancer.

Despite a large number of studies indicating that celecoxib plays an important role in the prevention and treatment of tumors, the detailed molecular mechanisms are not well understood. The aim of the present study was to investigate the effect of celecoxib on insulin-like growth factor 1 (IGF-1)-induced growth and invasion in non-small cell lung cancer (NSCLC). For these experiments, IGF-1-induced cell growth and invasion were analyzed in A549 cells in the presence and absence of celecoxib. The effects of celecoxib on the expression of phosphorylated type-1 IGF receptor (IGF-1R) and phosphorylated AKT (p-AKT) were examined using western blot analysis. The influence of celecoxib on IGF-binding protein-3 (IGFBP-3) expression was analyzed using ELISA. Celecoxib inhibited IGF-1-stimulated growth and invasion in a dose-dependent manner. Celecoxib also reduced the expression of IGF-1R, IGFBP-3 and phosphorylation of AKT. The results suggest that modulating the IGF axis may be a new mechanism for the anticancer effect of celecoxib on NSCLC.