Latest ArticlesZeolites are crystalline porous materials that are used in the chemical industry for adsorption, separation and catalytic reactions. Chiral zeolites have shown promise in enantioselective adsorption and catalytic organic reactions, attracting significant research interest. Recent advances have been made in the rational design, computational prediction and hydrothermal synthesis of using chiral organic structure-directing agents. Additionally, newly developed electron microscopic techniques have been utilized to analyze the structure and determine absolute configuration. The following review aims to provide an overview of the development history of chiral zeolites, examine several prominent chiral zeolite structures discovered so far, discuss the recent progress in characterization methods and explore their potential applications.
Efficient yield of 1O2 determines the photocatalytic degradation rate of antibiotics, but the regulatory mechanism for 1O2 selective generation in O2 activation is still lacking exploration. Herein, oxygen vacancy (OV) modification strategy of MIL-125 was successfully practiced to promote the selective generation of 1O2. Multiple characterizations including extended X-ray absorption fine structure (EXAFS) and electron paramagnetic resonance spectra (EPR) confirmed the formation of oxygen vacancy in OV-MIL-125. The synthesized OV-MIL-125 exhibited greatly enhanced 1O2 selective (~90%) and antibiotics removal rate in water with high mineralization rate. Dynamics analysis of excitons by transient-steady state fluorescence and phosphorescence, transient absorption spectra (TAS) revealed that oxygen vacancy greatly enhanced the intersystem crossing (ISC) of singlet exciton, promoting triplet exciton generation. Density functional theoretical (DFT) calculation also proved the reduced gap of intersystem (ΔEST) and the modulated highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) population which was conducive to intersystem crossing process. Calculation of transition state further confirmed the lower energy barrier for π* orbital spin flip of O2 adsorbed on OV-MIL-125. The Dexter energy transfer involving triplet annihilation dominated the O2 activation mechanism to generate 1O2 instead of the charge transfer to generate O2•− which happened in MIL-125. This study provides new thinking for photocatalytic activation of molecular oxygen and is expected to guide the design of MOF-based catalysts for water treatment.
Spinel oxides, with the formula AB2O4 (A and B represent metal ions) perform superior electrocatalytic characteristic when A and B are transition metals like Co, Fe, Mn, etc. Abundant researches have been attached to the structure designments while methods are often energy-intensive and inefficient. Here, we devised a universal strategy to achieve rapid synthesis of nanocrystalline spinel materials with multiple components (Co3O4, Mn3O4, CoMn2O4 and CoFe2O4 are as examples), where phase formation is within 15 s. Under the Joule-heating shock, a crack-break process of microcosmic phase transformation is observed by in-situ transmission electron microscopy. The half-wave potential values of Co3O4—JH, Mn3O4—JH, CoMn2O4—JH and CoFe2O4—JH in the electrocatalytic oxygen reduction reaction were 0.77, 0.78, 0.79 and 0.76, respectively. This suggests that the Joule heating is a fast and efficient method for the preparation of spinel oxide electrocatalysts.
This review profiles twelve fluorine-containing drugs approved by the US Food and Drug Administration (FDA) for the clinic in 2023. These small molecule drugs represent such therapeutic areas as cancer, neuromuscular disorder, immunodeficiency, virology, and infectious diseases. Medicinal chemistry discovery, biological activity, and synthetic routes have been discussed for each drug. Also, new trends in structural positioning, functionality, and degree of fluorination are discussed. Besides fluorination, the importance of amino acid residues and chirality in the design of new pharmaceuticals is highlighted.
A novel approach was developed to fabricate a label-free electrochemical aptasensor for specific detection of mercury ions (Hg2+). This involved modifying polylysine (PLL)-coated black phosphorus-porous graphene (BP-PG) nanocomposites (PLL/BP-PG) onto the surface of glassy carbon electrodes (GCE), which were further modified with gold nanoparticles (AuNPs) to combine with a thiolated aptamer (Apt) capable of specifically recognizing Hg2+. BP-PG was synthesized using the solvothermal method and covalently bonded to form BP-PG nanosheets, resulting in significant enhanced electrochemical properties of the PLL/BP-PG composite. Furthermore, the PLL/BP-PG composite was improved environmental stability of BP and provided a considerable quantity of -NH2 for bonding to AuNPs firmly by assembling. The physical properties and electrochemical behavior of the substrate materials were investigated using various characterization techniques, and analytical parameters were optimized. It is shown that, the Apt/AuNPs/PLL/BP-PG/GCE had a linear response (R2 = 0.999) with good selectivity and high sensitivity over the Hg2+ range of 1–10,000 nmol/L. The proposed sensor has a detection limit of 0.045 nmol/L and can be employed for detecting of Hg2+. It also obtained satisfying results in river water, soil and vegetable samples.
Effective design of nanoheterostructure anode with high ion/electron migration kinetics can give electrode with superior electrochemical performance. However, the design and preparation of nanoheterostructure composites with high-capacity and long cycling life in half and pouch full cells remain a big challenge. Here, a novel micro-pore MnS/Mn2SnS4 heterostructure nanowire were in situ encapsulated into the N and S elements co-doped amorphous carbon tubes (abbreviated as (MnS/Mn2SnS4)@N,S-ACTs) and showed superior energy storage properties in Na-/Li-ion half cells and pouch full cells. The Na-/Li-storage capabilities improvement are attribute to the strong synergistic effect between MnS/Mn2SnS4 heterostructure and N,S-ACTs protective layer, the former induces an local built-in electric field between Mn2SnS4 and MnS during charging/discharging, accelerating interfacial ion/electron diffusion dynamics, the latter effective maintains the morphology and volume evolution during Na+/Li+ charging/discharging, achieving a long-term cycling stability (e.g., high discharge capacity of 79.2 mAh/g with the capacity retention of 79.3% can be gained after 2200 cycles at 3 C in (MnS/Mn2SnS4)@N,S-ACTs//LiFePO4 pouch full cells; a high capacity of ~34 mAh/g at 10 C can be got with a Coulombic efficiency of 100% after 1000 cycles in pouch (MnS/Mn2SnS4)@N,S-ACTs//Na3V2(PO4)2O2F full cells.
Multi-response metal cluster supercrystal materials, which can simultaneously display various such as color, photoluminescence, changes by bearing only one stimulus, have huge potential as stimuli-responsive intelligent material, but are rarely reported. Here, we report three Cu8 cluster supercrystals, Cu8-1, Cu8-2, and Cu8-3, with homologous cluster molecule units [Cu8(PNP)3(EPPTA)6](PF6)2 but distinct packing. These supercrystals display bright µs-long photoluminescence with a high quantum yield of up to 26.6% in solid-state at room temperature and aggregation-induced emission (AIE) characteristic. Superior thermal stability and blue-excitable bright yellow emission make Cu8-3 serve as a yellow phosphor for white light-emitting diode. Furthermore, upon being stimulated by solvent vapor and temperature, reversible supercrystal-to-supercrystal transformations can be witnessed accompanied by remarkable color and luminescence switching. This work not only provides a kind of Cu cluster supercrystal model but also motivates the further development of metal clusters in multi-response materials.
Conventionally, organic radicals adhere to the Aufbau principle, the energy level of the singly occupied molecular orbital (SOMO) is not below the highest occupied molecular orbital (HOMO), but somewhat abnormal phenomena have appeared recently. In this study, we introduce a novel strategy by incorporating unique NHC-Au-X units into a tris(2,4,6-trichlorophenyl)methyl (TTM) system to create metal-involved open-shell complexes, denoted as TTM-NHC-Au-X (X = I, Br, or Cl). Density-functional theory calculations were used to predict an inversion in the energy of the SOMO and highest doubly occupied molecular orbital (HOMO) of TTM-NHC-Au-I, which is supported by experimental results. Organometallic radicals TTM-NHC-Au-X demonstrated distinct properties with different coordinated halides. The radical behaviors have been investigated by EPR, UV–vis spectroscopy and cyclic voltammetry, additional structural information provided by structurally comparing related the precursor complexes given by X-ray crystallography. TTM-NHC-Au-I with SOMOHOMO conversion (SHC) features a highly thermal decomposition temperature up to 305 ℃. Furthermore, the photostability of TTM-NHC-Au-I was found to be 75 and 23 times greater than that of TTM-NHC-Au-Br and TTM-NHC-Au-Cl, respectively. These findings provide valuable insights into the structural and electronic design principles governing the occurrence of SOMOHOMO conversion in open-shell systems.
Oxygen evolution reaction (OER), occurring at the anode of electrochemical water splitting requires a comprehensive understanding of oxygen electrocatalysis mechanism to optimize its efficiency. Atomically dispersed transition metal supported by nitrogen-doped carbon is featured with excellent catalytic performance. Herein, we report a Mg/Co bimetal site which utilizes Mg 3p electrons with strong binding of *OH (the first key reaction intermediates in the free energy diagram) to trigger the OER reaction and Co 3d itinerant character to regulate the binding strength of *O. Benefiting from the fine-tuned adsorption/desorption possesses, the optimized catalyst delivers superior OER activity with low overpotential, i.e., 310 mV at a current density of 10 mA/cm2 and 455 mV at 100 mA/cm2. Moreover, the current density is able to be maintained at 10 mA/cm2 for 10 h, consistent with the theoretical simulations for oxidization process, which demonstrates stable configurations after multiple *OH modification, revealing robust applicability in alkaline medium.
Melanoma treatment has been revolutionized with the development of targeted therapies and immunotherapies, which shows a positive influence on the patients. However, the long-term efficaciousness of such therapy is restricted by side effects, limited clinical effects as well as quick resistance to treatment. In this work, we prepared magnetocaloric carrier-free bimetallic hydrogels, named manganese-iron oxide nanocubes@polyethylene glycol-hydrogels (MFO@PEG-Gels), to realize ion-interferential cell cycle arrest for melanoma treatment. In detail, the tumor site was exposed to alternating magnetic field (AMF) after intratumorally injected MFO@PEG-Gels, which generated hyperthermia and promoted the sol-gel phase transition for MFO sustained release. Under the tumor microenvironment, hydrogen peroxide triggered MFO degradation to induce Mn2+ and Fe3+ release. On one hand, Mn2+ blocked G1/S phase through the activation of p27 pathway. On the other hand, Fe3+ could arrest the G2/M phase by upregulating the polo-like kinase 4 (PLK4) expression as well as inhibiting autolysosome formation to achieve the enhanced cell cycle arrest, thereby promoting the apoptosis of melanoma cells. In summary, this study proposed ion-interferential cell cycle arrest strategy by a multifunctional and injectable magnetic bimetallic hydrogel for melanoma treatment, which provided a secure and sustainable regimen for enhancing anti-tumor efficacy.
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