Chemical record最新文献

The application of group 13 compounds to coordination polymerization has been widely investigated. For example, cationic transition-metal catalysts are associated with a counteranion containing aluminum and boron. Furthermore, boron- and aluminum-functionalized monomers for olefin polymerization are recognized as precursors for functionalized polyolefin via versatile transformations. Recently, we have found many examples that boron and aluminum-based activators play a crucial role in improving the activity and regio/stereospecificity, and this review summarizes these achievements in detail, including modifications of methylaluminoxane (MAO) and the development of Brønsted acidic cyclic fluoroarylborane cocatalyst. Moreover, our recent progress on the copolymerization of vinyl monomers containing boronic acid derivatives is introduced. The synthesized boron-functionalized polyolefins are applied to high-performance plastics and reprocessable rubber materials.

Considering their interesting electronic and photonic properties, the 4,4-difluro-4-bora-3a, 4a-diaza-s-indacene (BODIPY)-based molecular probes are the cynosure in the current times. Their unique properties, such as easy functionalization through simple synthetic modifications, strong absorption and more importantly, the high fluorescence quantum yields, are the key attributes required for several Hi-tech applications. Consequently, in the last few decades, many research groups have diverted their attention to developing BODIPY-based materials for a wide range of applications. Motivated by the literature reports, in our previous review on this topic, we reported on systematic progress in the use of BODIPY-based derivatives in bioimaging applications covering the reports that appeared during 2014-2019. Since the BODIPY derivatives continue to inspire with their unique characteristics with the fascinating photophysical properties, in this present review we have surveyed the very representative and recent (2020 onwards) advancement in the applications of BODIPY-based molecular derivatives to catalysis, singlet oxygen generation and white light emission rationalised by the photoredox/electron transfer/energy transfer processes, and hope that this should be useful update to existing reviews on these topics.

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.