Chemical record最新文献

The high reactivity and immediate accessibility of 1,3-enynes render them versatile foundational units in the synthesis of highly valuable molecular structures, encompassing propargylic, allene, and diene compounds, in addition to carbo- and heterocyclic compounds. Transition-metal catalyzed 1,4-difunctionalization of 1,3-enynes represents one of the most powerful approaches that has attracted the attention of chemists. In this review, the functionalization and annulation reactions of 1,3-enynes under various transition metal-catalyzed systems are highlighted.

The development of sustainable and low-cost energy storage and conversion systems is crucial for modern society. To enable large-scale implementation, research has focused on synthesizing eco-friendly and cost-effective components, particularly electrolytes and electrodes, for electrochemical devices such as fuel cells, supercapacitors, and batteries. Carbon-based materials are widely employed as electrodes or catalyst supports, and biomass-derived carbons have emerged as attractive alternatives due to their abundance, renewability, and low cost. The physicochemical and electrochemical properties of biomass-derived activated carbons (ACs) including porosity, surface area, and electrical conductivity strongly depend on their synthesis and activation processes. This review analyzes the preparation of ACs from various biomass sources, emphasizing pyrolysis in tubular furnaces and the influence of parameters such as activation temperature, time, gas flow rate, and carbonization conditions. The relationships between these parameters and the resulting structural and electrochemical properties are discussed, with a particular focus on plant-derived carbons. Finally, the applications of biomass-derived ACs as electrode materials in different electrochemical systems are summarized, highlighting how precursor type and synthesis route govern their performance and suitability for sustainable energy technologies.

Some organic molecules exhibit multiple properties such as chiral crystal formation, crystal polymorphism, room-temperature phosphorescence, mechanochromism, and fluorescence detection by molecular recognition only in their solid, self-aggregated states (crystalline or amorphous states). These functionalities either disappear or converge to a single physical property when these molecules are dispersed in a solvent. To address this limitation, self-aggregated guest molecules are dissolved in water using natural polymers as solubilizing agents. However, conventional solid-liquid extraction methods such as heating and stirring or ultrasonic irradiation are rendered ineffective in completely dissolving the functional guest molecules in water. These molecules are mixed with natural polymers via grinding or high-speed vibration milling, followed by extraction with water, to enhance their water solubility while maintaining their functions. These systems are referred to as aqueous solutions with information (properties) on solids.

Polyquinanes are well known for their fused five-membered rings, and they represent structurally complex and biologically significant frameworks found in several natural products. This account highlights the use of norbornene derivatives as key building blocks in synthesizing various polyquinane scaffolds by employing advanced olefin metathesis (OM) strategies. Norbornene's reactivity is due to inherent strain energy and this reactivity promotes various synthetic transformations via ring-opening metathesis (ROM), ring-closing metathesis (RCM), and ring-rearrangement metathesis (RRM), enabling the precise bond reorganization that allows the construction of diverse linear, angular, and propellane types of polyquinane architects along with the higher order tetraquinanes and pentaquinanes. Diels–Alder adducts (DAA) derived from norbornene precursors further enhanced the modularity of these synthetic routes. Such approaches enabled an efficient assembly of cis–anti–cis and cis–syn–cis stereochemical motifs, overcoming challenges posed by strained ring systems and regioselective issues. Moreover, when the metathetic strategies are combined with Diels–Alder reaction (DAR), the complexity in the target molecules can rise quickly due to synergistic effect. These synthetic approaches efficiently construct tetraquinanes and pentaquinanes with intricate stereochemistry that allows the access of natural products and their analogs. These findings highlight the expanded use of alkene metathesis in constructing complex molecular architectures, emphasizing its crucial role in modern organic synthesis and drug development.

This account overviews our synthetic strategies for natural products featuring benzochromanone and benzochromene frameworks. The total synthesis of monomeric benzochromanones, particularly xanthones and benzochromanones is achieved. Key accomplishments include the development of a versatile synthetic approach for constructing xanthone frameworks via spirochromanone intermediates and the successful total syntheses of (±)-4-deoxyblennolide C, (+)-blennolide C, and chromanone lactone gonytolide C. The asymmetric total synthesis of benzochromene (R)-(+)-teretifolione B and the first asymmetric synthesis of (R)-(+)-methylteretifolione B are also achieved. The Diels-Alder reaction between benzyne derived from chromene precursors and oxygenated furans enabled efficient access to benzochromene derivatives. The enantioselective synthesis of teretifolione B and related compound was accomplished through the enzymatic resolution of racemic chromenes, and the reaction conditions were investigated to improve regioselectivity in key steps. These synthetic routes provide access to a diverse array of benzochromanone and benzochromene derivatives with potential biological activity.

This review critically examines the environmental implications of metalloids, with a focus on their role in industrial applications and the resulting ecological challenges. It addresses the dual nature of metalloids, emphasizing their beneficial uses while highlighting contamination and toxicity issues in soil, water, and atmospheric systems. The analysis evaluates specific environmental challenges associated with each metalloid and assesses both conventional and innovative remediation techniques, with a particular focus on bioremediation and nanoremediation technologies. Recent advancements in these areas are explored, offering insights into the mechanisms of metalloid transport and contamination. The review advocates for sustainable remediation strategies and promotes an integrated approach to managing metalloid pollution, aiming to protect environmental health and enhance sustainability.

Silicon quantum dots (SiQDs) are an emerging class of high-performing, sustainable, environmentally safe luminescent nanomaterial. They offer opportunities for next-generation displays, solid-state lighting, medical applications, and quantum technologies. Here, we highlight recent breakthroughs in colloidal SiQD synthesis and photophysics, comparing eight synthetic strategies. Among these, we focus on the hydrogen silsesquioxane (HSQ) polymer route, a simple and cost-effective hot-injection-free method that yields highly crystalline, ultrabright, and stable SiQDs with photoluminescence quantum yields approaching 80%. We also describe how solvent engineering realizes SiQD light-emitting diodes (LEDs) with record external quantum efficiencies (EQEs, >16%), >700-fold-increased lifetimes, and far-red emissions to rival state-of-the-art perovskite QD LEDs. Moreover, rice husk-derived SiQD LEDs illustrate the potential for low-waste circular material cycles. Thus, SiQDs are a sustainable platform for plant growth technologies, photodynamic therapy, and beyond.

Mechanofluorochromism (MFC) is a photophysical phenomenon in which the color and fluorescent color of solid-state organic or metal complex fluorescent dyes change upon external mechanical stimulation (grinding) and recover to their original ones upon heating or exposure to solvent vapor. We discovered that newly developed donor-π-acceptor (D-π-A) fluorescent dyes exhibit bathochromic or hypsochromic-shifted MFC (b-MFC or h-MFC). This MFC arises from reversible switching between the crystalline and amorphous states, accompanied by changes in dipole-dipole and intermolecular π-π interactions upon grinding and heating. Indeed, such MFC not only is of a great scientific interest in photochemistry and photophysics but also has great potential for development of smart materials for next-generation optoelectronic devices, including rewritable photoimaging and electroluminescence devices. In this Personal Account, we offer an insight into the mechanism for the expression of MFC and present molecular design directions for creating D-π-A-type mechanofluorochromic dyes which can exhibit b-MFC or h-MFC.

Propargylic alcohol is a shining star in the chemical space. These congeners have garnered significant attention from the synthetic chemistry community due to their dual functionality and three-centered reactivity. In this realm, the electrophilic cyclization of propargylic alcohols with a tethered nucleophile functional group is a key strategy for synthesizing hetero- and carbocycles. In these transformations, the position of the nucleophilic reactive handle can influence the reaction outcome. Consequently, these derivatives open up numerous opportunities to create complex cyclic adducts through various reaction pathways. Among all nucleophile tethers, the hydroxy group has been increasingly used in the production of oxy-heterocyclics. The hydroxy dialing on the core propargylic alcohol would lead to oxy-heterocyclics, such as benzofuran, furan, chromene, coumarin, chromone, pyrane, etc., which have numerous applications in various fields of biology and other scientific fields. In this review, we focused on uncovered hydroxy-tethered propargylic alcohol cyclization reactions. We categorized these transformations based on the structural features of hydroxy propargylic alcohols. With this review, we aim to pave the way for further efforts in discovering new reaction pathways.

Excited-state intramolecular proton transfer (ESIPT) happens when a molecule, upon photon absorption, is promoted to an electronically excited state, where a proton transfer occurs from a donor to an acceptor group within the molecule. This process generates an excited-state tautomer, often exhibiting a lower ionization potential. Consequently, the fluore scence spectra display a notable Stokes shift, with emission peaks shifted toward longer wavelengths. More details can be found in the Review by Rampal Pandey, Mrituanjay D. Pandey, and co-workers (DOI: 10.1002/tcr.202500109).