Induced Aggregation, Solvent Regulation, and Supracluster Assembly of Aluminum Oxo Clusters.

ConspectusRecent years have witnessed the development of cluster materials as they are atomically precise molecules with uniform size and solution-processability, which are unattainable with traditional nanoparticles or framework materials. The motivation for studying Al(III) chemistry is not only to understand the aggregation process of aluminum in the environment but also to develop novel low-cost materials given its natural abundance. However, the Al-related clusters are underdeveloped compared to the coinage metals, lanthanides, and transition metals. The challenge in isolating crystalline compounds is the lack of an effective method to realize the controllable hydrolysis of Al(III) ions. Compared with the traditional hydrolysis of inorganic Al(III) salts in highly alkaline solutions and hydrolysis of aluminum trialkyl compounds conducted carefully in an inert operating environment, we herein developed an effective way to control the hydrolysis of aluminum isopropanol through an alcoxalation reaction. By solvothermal/low melting point solid melting synthesis and using "ligand aggregation, solvent regulation, and supracluster assembly" strategies, our laboratory has established an organic-inorganic hybrid system of aluminum oxo clusters (AlOCs). The employment of organic ligands promotes the aggregation and slows the hydrolysis of Al(III) ions, which in turn improves the crystallization process. The regulation of the structure types can be achieved through the selection of ligands and the supporting solvents. Compared with the traditional condensed polyoxoaluminates, we successfully isolated a broad range of porous AlOCs, including aluminum molecular rings and Archimedes aluminum oxo cages. By studying ring expansion, structural transformation, and intermolecular supramolecular assembly, we demonstrate unique and unprecedented structural controllability and assembly behavior in cluster science. The advancement of this universal synthetic method is to realize materials customization through modularly oriented supracluster assembly. In this Account, we will provide a clear-cut definition and terminology of "ligand aggregation, solvent regulation, and supracluster assembly". Then we will discuss the discovery in this area by using a strategy, such as aluminum molecular ring, ring size expansion, ring supracluster assembly, etc. Furthermore, given the internal and external pore structures, as well as the solubility and modifiability of the AlOCs, we will demonstrate their potential applications in both the solid and liquid phases, such as iodine capture, the optical limiting responses, and dopant in polymer dielectrics. The strategy herein can be applied to extensive cluster science and promote the research of main group element chemistry. The new synthetic method, fascinating clusters, and unprecedented assembly behaviors we have discovered will advance Al(III) chemistry and will also lay the foundation for functional applications.

Assembly of Homochiral Aluminum Oxo Clusters for Circularly Polarized Luminescence.

Chiral aluminum oxo clusters (cAlOCs) are distinguished from other classes of materials on account of their abundance in the earth's crust and their potential for sustainable development. However, the practical synthesis of cAlOCs is rarely known. Herein, we adopt a synergistic coordination strategy by using chiral amino acid ligands as bridges and auxiliary pyridine-2,6-dicarboxylic acid as chelating ligands and successfully isolate an extensive family of cAlOCs. They integrate molecular chirality, absolute helicity, and intrinsic hydrogen-bonded chiral topology. Moreover, they have the structural characteristics of one-dimensional channels and replaceable counteranions, which make them well combined with fluorescent dyes for circularly polarized luminescence (CPL). The absolute luminescence dissymmetry factor (glum) of up to the 10-3 order is comparable to several noble metals, revealing the enormous potential of cAlOCs in low-cost chiral materials. We hope this work will inspire new discoveries in the field of chirality and provide new opportunities for constructing low-cost chiral materials.

Carborane-Cluster-Wrapped Copper Cluster with Cyclodextrin-like Cavities for Chiral Recognition.

Chiral atomically precise metal clusters, known for their remarkable chiroptical properties, hold great potential for applications in chirality recognition. However, advancements in this field have been constrained by the limited exploration of host-guest chemistry, involving metal clusters. This study reports the synthesis of a chiral Cu16(C2B10H10S2)8 (denoted as Cu16@CB8, where C2B10H12S2H2 = 9,12-(HS)2-1,2-closo-carborane) cluster by an achiral carboranylthiolate ligand. The chiral R-/S-Cu16@CB8 cluster features chiral cavities reminiscent of cyclodextrins, which are surrounded by carborane clusters, yet they crystallize in a racemate. These cyclodextrin-like cavities demonstrated the specific recognition of amino acids, as indicated by the responsive output of circular dichroism and circularly polarized luminescence signals of Cu16 moieties of the Cu16@CB8 cluster. Notably, a quantitative chiroptical analysis of amino acids in a short time and a concomitant deracemization of Cu16@CB8 were achieved. Density functional tight-binding molecular dynamics simulation and noncovalent interaction analysis further unraveled the great importance of the cavities and binding sites for chiral recognition. Dipeptide, tripeptide, and polypeptide containing the corresponding amino acids (Cys, Arg, or His residues) display the same chiral recognition, showing the generality of this approach. The functional synergy of dual clusters, comprising carborane and metal clusters, is for the first time demonstrated in the Cu16@CB8 cluster, resulting in the valuable quantification of the enantiomeric excess (ee) value of amino acids. This work opens a new avenue for chirality sensors based on chiral metal clusters with unique chiroptical properties and inspires the development of carborane clusters in host-guest chemistry.

Balloon angioplasty as first-choice recanalization strategy for intracranial atherosclerosis-related emergent large vessel occlusion with small clot burden.

PURPOSE: The optimal primary recanalization strategy for intracranial atherosclerosis-related emergent large vessel occlusion (ICAS-ELVO) remains controversial. We aimed to explore the safety and efficacy of balloon angioplasty as the first-choice recanalization strategy for ICAS-ELVO with small clot burden. METHODS: Consecutive ICAS-ELVO patients presenting with microcatheter "first-pass effect" during endovascular treatment (EVT) were retrospectively analyzed. Patients were divided into preferred balloon angioplasty (PBA) and preferred mechanical thrombectomy (PMT) groups based on the first-choice recanalization strategy. The reperfusion and clinical outcomes between the two groups were compared. RESULTS: Seventy-six patients with ICAS-ELVO involving the microcatheter "first-pass effect" during EVT were enrolled. Compared with patients in the PMT group, those in the PBA group were associated with (i) a higher rate of first-pass recanalization (54.0% vs. 28.9%, p = .010) and complete reperfusion (expanded thrombolysis in cerebral ischemia ≥ 2c; 76.0% vs. 53.8%, p = .049), (ii) shorter puncture-to-recanalization time (49.5 min vs. 89.0 min, p < .001), (iii) lower operation costs (¥48,499.5 vs. ¥ 99,086.0, p < .001), and (iv) better 90-day functional outcomes (modified Rankin scale:0-1; 44.0% vs. 19.2%, p = .032). Logistic regression analysis revealed that balloon angioplasty as the first-choice recanalization strategy was an independent predictor of 90-day excellent functional outcomes for ICAS-ELVO patients with microcatheter "first-pass effect" (adjusted odds ratio = 6.01, 95% confidence interval: 1.15-31.51, p = .034). CONCLUSION: Direct balloon angioplasty potentially improves 90-day functional outcomes for ICAS-ELVO patients with small clot burden, and may be a more appropriate first-choice recanalization strategy than mechanical thrombectomy for these patients.

Designed Synthesis of an Aluminum Molecular Ring Based Rotaxane and Polyrotaxane.

Mechanically interlocked molecules, such as rotaxanes, have drawn significant attention within supramolecular chemistry. Although a variety of macrocycles have been thoroughly explored in rotaxane synthesis, metal-organic macrocycles remain relatively under-investigated. Aluminum molecular rings, with their inner cavities and numerous binding sites, present a promising option for constructing rotaxanes. Here, we introduce an innovative "ring-donor···axle-acceptor" motif utilizing Al8 molecular rings, enabling the stepwise assembly of molecules, complexes, and polymers through tailored coordination chemistry. This novel approach can not only be applied to macrocycle-based systems like catenanes but also enhance specific functionalities progressively.

A new species and new records of Hymenopellis and Xerula (Agaricales, Physalacriaceae) from China.

Hymenopellis is the genus that exhibits the highest number of species within the Xerula/Oudemansiella complex. Numerous species of Hymenopellis demonstrate edibility, and some of these species have been domesticated and cultivated. During an extensive survey carried out in Henan and Jilin Provinces, China, a substantial quantity of Hymenopellis specimens was gathered as a component of the macrofungal resource inventory. Based on the findings of morphological and molecular phylogenetic studies, a new species, Hymenopellis biyangensis, has been identified. A new record species, Hymenopellis altissima, has been discovered in China. Additionally, two new record species, Hymenopellis raphanipes and Xerula strigosa, have been found in Henan Province. Internal transcribed spacer (ITS) and large subunit ribosomal (nrLSU) were used to establish a phylogeny for species identification. Detailed descriptions, field habitat maps and line drawings of these species are presented. The discussion focuses on the relationships between newly discovered species and other related taxa. Additionally, this study provides and a key to the documented species of Hymenopellis and Xerula found in China.