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.

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.

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.

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.

The present review outlines the latest advances in bio-organometallic ferrocene chemistry carried out on the brain. The brain has emerged as a key target and model for iron-loading by bioactive ferrocene-based compounds. This review focuses on the in vivo, ex vivo, and in vitro experimental data using ferrocene compounds in the brain, and discusses recent findings regarding their mechanisms of action. It also provides an overview of the biomedical aspects of studying ferrocene derivatives. The objective of this mini-review is to show the potential of ferrocene-modified compounds for studying brain challenges.

Triazole, also known as Pyrrolidazole, is a fundamental framework in heterocyclic chemistry. This is a five-membered aromatic compound consisting of three nitrogen atoms and two carbon atoms, which exist in two isomeric forms:1,2,3-triazole and 1,2,4-triazole. Both isomers exhibit a diverse range of applications across various domains, including materials science, medicinal chemistry, and catalysis. Despite their well-established advantages, triazole moieties are utilized as significant components in OLEDs, data storage devices, and organic photovoltaics. This review particularly emphasizes the recent advancements from 2020 to 2025, focusing on the asymmetric synthesis of triazole scaffolds and highlighting key methodologies ranging from copper-catalyzed azide-alkyne cycloaddition to biocatalytic strategies. Several studies have been reported about the development of innovative chiral ligands in conjunction with transition metals, including Ni, Rh, and Ir, leading to noble, efficient, and selective catalytic systems. Moreover, the present review article specifically explores the broad substrate scopes, reaction scalability, and detailed mechanistic insights that underscore the synthetic utility and versatility of these protocols. In addition, biocatalytic and chemoenzymatic approaches demonstrate the feasibility of sustainable and stereoselective synthesis of triazole-based antifungal agents. Overall, this mini-review not only guides the young researcher to develop new methodologies by carefully weighing their pros and cons but also equally assists the industrial scientist in designing bioactive heterocyclic compounds.

Excited state intramolecular proton transfer (ESIPT) is a process where photoexcited molecules dissipate energy by transferring protons and undergoing tautomerization. With a brief introduction of a new emerging sensing mechanism, viz., CN isomerization, AIE, etc., this study explores the various aspects of ESIPT based on the current studies. Since Weller discovered ESIPT in salicylic acid and methyl salicylate, extensive research has developed on this topic, attributing to its wide applications. Here, it explores the structural and mechanical aspects of ESIPT and tautomerization.

The bioconjugation of aromatic amino acids has emerged as a powerful strategy in chemical biology, drug discovery, and biomolecular research. Beyond the classical targeting of cysteine and lysine, aromatic amino acids residues offer higher selectivity owing to their lower abundance and critical roles in intermolecular interactions. Current synthetic approaches include substitution reactions, addition reactions, free-radical reactions, metal-catalyzed transformations, and biocatalytic approaches, enabling precise and versatile modifications in cells, tissues, and at the proteome level. In recent years, transition-metal catalysis and radical processes have dominated the field, with particular emphasis on tyrosine and tryptophan. This review provides a critical analysis of advances from the past 3 years, categorizing methodologies by reaction mechanism and highlighting how the intrinsic reactivity of aromatic amino acids can be harnessed for site-selective functionalization, ultimately expanding the accessible chemical space across all these residues.

This personal account offers a detailed and creative comparison of methods for synthesizing gold nanoparticles (AuNPs) using pamoic acid (PA) and, crucially, states what this route delivers in practice. Specifically, we show that the PA-capped approach enables (i) one-pot, room-temperature synthesis with intrinsic carboxylate functionalization and no thiolated linkers; (ii) decade-scale colloidal stability; (iii) reproducible size control from ~10 to 15 nm spheres to ~75 nm via pH/seed tuning, with extension to anisotropic shapes by secondary growth; and (iv) excellent biocompatibility supported by in vitro and in vivo assays. We benchmark application performance: PA-AuNPs deliver high catalytic/electrocatalytic activity (e.g., 4-nitrophenol reduction turnover frequencies on the order of 10 h), sensitive electroanalysis (ketoconazole detection down to low-μM), and fluorescence sensing that exploits PA's chromophore (levofloxacin limits of detection in the tens of nM). We further provide a focused techno-economic and scalability assessment showing that 100 mL of a 6 × 10 particles mL dispersion can be produced at bench scale for ~$2.26, with >90% of cost attributable to HAuCl, and outline an industrial flowsheet (20 m) with minimal energy and maintenance demands. Taken together, these findings demonstrate the commercial potential of PA-capped AuNPs for biosensing, drug delivery, imaging, environmental remediation, analytical chemistry, and energy conversion/storage, while emphasizing their ecological friendliness and operational simplicity relative to conventional citrate and sulfur-anchored strategies. We conclude by identifying key research gaps, standardized reporting, ligand fate in complex media, and scale-transition controls that will accelerate mechanism-resolved studies and industrial translation.

Alkyne is one of the simplest yet important functional group in organic synthesis. The richness of this entity renders it as an extremely versatile synthon for developing a diverse array of modern strategies for assembly of different heterocycles. This account describes the research efforts of more than a decade on the usage of alkynes as nucleophiles, electrophiles, and radical precursors for the synthesis of diverse set of heterocycles and the utilization in the total synthesis of structurally simple to complex bioactive natural products.

Thiazolotriazole is gaining attention in medicinal chemistry due to its wide spectrum of biological activity. It is a fused heterocyclic compound formed by the fusion of 1,3-thiazole and 1,2,4-triazole, and the type of ring fusion results in the formation of isomeric thiazolotriazoles-[3,2-b] or [2,3-c] isomers. The synthesis of both ring systems has been carried out by various methodologies ranging from conventional methods such as cyclization and annulation to the use of metal catalysts, microwave radiation, photochemical and multicomponent reactions. In drug discovery, thiazolotriazole derivatives have been primarily investigated for their antibacterial, anticancer, anti-inflammatory, and antifungal properties. Recent years have seen significant advancements in anticancer drug research, revealing that these molecules are potential anticancer agents interacting with specific targets or biochemical pathways responsible for apoptosis and proliferation. In addition, thiazolotriazole also exhibits analgesic, anticonvulsant, antidiabetic, and antioxidant activities. Furthermore, thiazolotriazoles have also demonstrated the potential to inhibit enzymes such as carbonic anhydrase, urease, cyclooxygenase, and butyrylcholinesterase, which are meant to have particular biological functions. In the context of various applications, a review that describes biological activities with a particular focus on structural attributes that contribute to the activity will be helpful to better understand structure-activity relationship (SAR) and guide for further design of bioactive thiazolotriazoles. This review explains the biological activity of thiazolotriazole highlighting SAR and drug targets for specific disease conditions which will be helpful to better understand the scaffold and apply this knowledge to future drug discovery on thiazolotriazoles.

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.

Nitric oxide (NO) is one of the most extensively studied small inorganic molecules involved in biological signaling processes related to both health and disease. Many biological transformations that depend on NO rely on bioinorganic chemistry, where both redox-active and nonredox-active inorganic centers and processes play crucial roles. This review covers several key topics, including the role of heme centers in NO biosynthesis and metabolism, the function of non-heme iron in NO bioactivity, and the interplay between calcium-dependent proteins and NO signaling pathways. It also discusses the involvement of free and bound copper ions, zinc ions, and zinc proteins in NO biosynthesis and its signaling pathways is discussed. The review also examines the role of molybdenum proteins in maintaining NO homeostasis and explores the biological activities associated with the interactions between NO and other reactive nitrogen species (RNS) with bioactive molecules containing cobalt. Furthermore, the regulation of NO signaling by selenoproteins is addressed. Additionally, we focus on NO signaling through S-nitrosation and nitration, highlighting the impact of both bound and free metal ions on the formation and fate of S-nitrosothiols.

Electrocatalysis plays a pivotal role in sustainable energy conversion and storage, yet the development of high-performance, stable, and cost-effective catalysts remains a significant challenge. Nanoring-structured electrocatalysts have emerged as superior alternatives to conventional nanoparticles, offering unique geometric and electronic advantages including maximized atomic utilization, strain-modulated active sites, enhanced mass/electron transfer, and exceptional stability. This article systematically examines their structure-performance relationships through theoretical and in situ experimental insights, showcasing representative applications in key electrocatalytic reactions, such as the oxygen evolution reaction, hydrogen evolution reaction, oxygen reduction reaction, alcohol oxidation reaction, CO reduction reaction, and nitrate reduction reaction, where nanoring catalysts consistently outperform their nanoparticle counterparts. Finally, we further identify critical challenges in precise synthesis, stability mechanisms, and advanced characterization, providing guidance for designing more effective electrocatalysts toward sustainable energy applications.

Transition-metal-catalyzed carbonylation and carboxylation reactions represents one of the dominant fields of synthetic chemistry, enabling the construction of structurally diverse and value-added carbonyl compounds. Although, different C surrogates have been developed to replace toxic carbon monoxide (CO), many of these require harsh acidic/basic conditions, metal catalysts, additives, or complex precursors, thereby generating substantial waste with lower atom economy. Herein, oxalic acid emanates as powerful multifaceted C synthon, capable of delivering CO, CO, and H through clean, additive-free thermal decomposition. The decomposition profile not only enables in situ gas generation but also uniquely positions oxalic acid as both a carbonyl source and reducing agent. Herein, this account highlights the development of oxalic acid from a traditional reagent to strategically important platform in sustainable synthesis. Special emphasis is placed on development of oxalic acid-mediated protocols for functionalized carboxylic acids, ketones, alkynones, thioesters, bis(indolyl)methanes, formamides, heterocycles, and carbocycles synthesis. Furthermore, innovative reaction system designs including single- and dual-vial systems that employed oxalic acid as sustainable in situ and ex situ gaseous surrogate have also been highlighted. Overall, this article underscores the practical utility of oxalic acid as a bench-stable, cost-effective, and environmentally benign trifunctional reagent, paving way for next-generation carbonylation chemistry aligned with green synthetic principles.

Smart and multifunctional cementitious composites have garnered significant interest due to their enhanced properties, including electrical and thermal conductivity, energy storage, self-healing, self-sensing, and chemical resistance, alongside their conventional structural functions. These advancements contribute to sustainability, energy efficiency, and improved structural performance. This review examines the potential of carbon-coated sand (CCS) as a novel additive in cement composites, emphasizing its ability to enhance mechanical strength, electrical conductivity, thermal stability, and other multifunctional characteristics. By integrating conductive and durable properties, CCS enables the development of self-sensing, self-healing, and energy-efficient cementitious materials. A comprehensive analysis of its synthesis, properties, and applications is presented, highlighting its role in improving durability and sustainability. Additionally, the challenges and future directions of incorporating carbon-coated sand into cementitious composites are explored. By bridging material science and civil engineering, this review aims to drive innovation in next-generation smart cement composites.

As a sustainable and clean energy source, hydrogen is gaining global recognition as a promising alternative to fossil fuels in the transition to a low-carbon economy. Its high energy density, versatility, and compatibility with renewable energy sources make it an attractive option for power generation, transportation, and industrial decarbonization. However, significant challenges hinder its widespread adoption, particularly in storage and transportation. Due to its low volumetric energy density, hydrogen requires advanced storage solutions such as chemical carriers, metal hydrides, compressed gas, and liquid hydrogen, each presenting unique financial and technological challenges. Additionally, transportation infrastructure-including pipelines and hydrogen carriers-must be further developed to enhance efficiency, improve safety, and minimize energy losses. Overcoming these challenges is essential to establishing a global hydrogen economy. Advancements in cost reduction, infrastructure development, and innovative storage materials are key to making hydrogen a viable mainstream energy source. This review highlights the critical barriers to hydrogen storage and transportation, while emphasizing the importance of continuous research, technological innovation, and supportive policies in accelerating the adoption of hydrogen for a cleaner, more sustainable energy future.

In this review, recently developed straightforward and efficient strategies for the construction of spirocyclic molecules are summarized. Cyclic 1,3-diketones serve as versatile synthons and can be employed in one-pot, single-step reactions as well as in multistep sequences and multicomponent processes with a variety of reacting partners, including aldehydes, ketones, amines, isatins, and acenaphthoquinone. These transformations can be facilitated either by using stoichiometric amounts of reagents or under catalytic conditions, including nanoparticle-supported systems, often resulting in significantly enhanced yields of the desired spirocycles. Some of the spirocyclic frameworks display a wide range of biological activities, showing efficacy against cancer, microbial, and fungal targets, and thus represent promising candidates for future medicinal chemistry and drug development.

Carbon-based single-atom nanozymes (CB-SANzymes) have garnered significant attention in recent years due to their unique ability to mimic the active sites of natural enzymes. They exhibit not only maximized atom utilization efficiency but also strong metal-substrate interactions that effectively modulate the electronic structure of metal centers. Furthermore, carbon substrates facilitate rapid electron transfer during biosensing processes and enhance the stability of single-atom sites. These advantages make CB-SANzymes highly promising for biosensing applications. This review examines the fundamental properties of CB-SANzymes and discusses strategies for their modifications. Key strategies include increasing single-atom density, tuning the coordination environment, leveraging multimetal synergy, and engineering carbon substrates via heteroatom doping and defect construction. We also summarize the recent advances of CB-SANzymes in diverse biosensing platforms, such as colorimetric, fluorescent, and electrochemical systems. Their contribution to enhancing the sensitivity, selectivity, and accuracy of these systems is emphasized. Finally, current challenges and future prospects in the development and application of CB-SANzymes are discussed, with the aim of providing insightful guidance for further advancements in this rapidly evolving field.