Mild Conditions Research Articles

The acylation of α-carbonyl sulfoxonium ylides with N-hydroxyphthalimide esters

A new method for the synthesis of 1,3-dicarbonyl sulfoxonium ylides is described. The acylation reaction is carried out in mild conditions using inexpensive and bench stable N-hydroxyphthalimide esters as acylating agents in a non-radical, transition-metal free pathway.

Potassium tert-Butoxide Promoted α-Keto Ester Synthesis via C(O)-N Bond Cleavage of Isatins

Here we present a novel and cost-effective method for synthesizing biologically important α-ketoesters in a single-step reaction. This approach involves a sequential cascade process within a single reaction vessel facilitated by KOtBu. It promoted cleavage of sp2 C(O)-N bond of isatins and new N-sp2 C(O) bond formation with benzoyl chloride. To our knowledge, this is the first instance of constructing the α-ketoester scaffold alongside an amide group through a one-pot process. In comparison to existing literature methods, our protocol offers several advantages: readily available starting materials, mild reaction conditions, a concise synthetic pathway, high sustainability, and excellent tolerance towards various functional groups. Given these strengths, we anticipate widespread use of this method in the synthesis of related α-ketoester scaffolds.

Photoredox-Catalyzed Difunctionalization of Alkenes with Sulfilimines.

Herein, we disclose a facile photoinduced difunctionalization of alkenes, enabling the synthesis of valuable β-amino alcohols, β-amino ethers, and 1,2-diamines with diverse nucleophiles. The protocol relies on the use of readily accessible dibenzothiophene-based sulfilimines as novel N-radical precursors, showcasing high functional-group tolerance and exclusive regioselectivity under mild reaction conditions.

Hypervalent iodine‐mediated regioselective dearomatization of non‐activated arenes

The dearomatizations of non‐activated arenes, particularly those under mild reaction conditions, are highly desired transformations in organic synthesis due to their power in converting flat aromatic rings into three‐dimensional frameworks. Although hypervalent iodine (HVI)‐mediated dearomatization of phenol derivatives has developed rapidly, HVI‐mediated dearomatization of non‐activated arenes remains an urgent and challenging task. To fulfil this task, in this work, we established an HVI‐mediated oxidative dearomatization of non‐activated arenes by using biphenylureas and N‐ or O‐nucleophiles as reactants. This electrophilic dearomatization (DEAr) process is highly regioselective, which enabled different N‐ and O‐nucleophiles to react at the distal C4‐position of the phenyl ring, thus generating dearomative spiro‐products in a single step under mild conditions with wide substrate scope (43 examples, 22%−76% yield). This approach not only provides a successful example for dearomatization of non‐activated arenes under mild reaction conditions, but also has overcome the challenges in HVI‐mediated dearomatization of non‐activated arenes, which will enrich the chemistry of dearomatization.

High-Entropy Metal-Organic Frameworks (HEMOFs): A New Frontier in Materials Design for CO2 Utilization.

High-entropy materials (HEMs) emerged as promising candidates for a diverse array of chemical transformations, including CO2 utilization. However, traditional HEMs catalysts are nonporous, limiting their activity to surface sites. Designing HEMs with intrinsic porosity can open the door toward enhanced reactivity while maintaining the many benefits of high configurational entropy. Here, a synergistic experimental, analytical, and theoretical approach to design the first high-entropy metal-organic frameworks (HEMOFs) derived from polynuclear metal clusters is implemented, a novel class of porous HEMs that is highly active for CO2 fixation under mild conditions and short reaction times, outperforming existing heterogeneous catalysts. HEMOFs with up to 15 distinct metals are synthesized (the highest number of metals ever incorporated into a single MOF) and, for the first time, homogenous metal mixing within individual clusters is directly observed via high-resolution scanning transmission electron microscopy. Importantly, density functional theory studies provide unprecedented insight into the electronic structures of HEMOFs, demonstrating that the density of states in heterometallic clusters is highly sensitive to metal composition. This work dramatically advances HEMOF materials design, paving the way for further exploration of HEMs and offers new avenues for the development of multifunctional materials with tailored properties for a wide range of applications.

Ce3+/Ce4+–TiO2 Nano‐Octahedra as Active Photocatalysts for Ciprofloxacin Photodegradation Under Solar Light

AbstractCerium‐containing titania nano‐octahedra (CeTNOh) are obtained by ultrasonication‐hydrothermal synthesis of Ce‐containing titanate nanowires (0.35, 0.46, and 0.70 Ce mol %) from commercial TiO2 (Degussa P25). CeTNOh are tested as photocatalysts to degrade a target pollutant (ciprofloxacin) under simulated solar light and at mild conditions. CeTNOh are anatase polymorphs with increasing crystallite size as Ce content increases. Hydrothermal treatments enhance the specific surface area (SSA) compared to P25, although Ce addition slightly reduces SSA while increasing crystallite size. Electron Microscopy confirms the morphology, although higher Ce levels hinder a full transformation. X‐ray photoemission spectroscopy (XPS) shows the presence of Ce3+/Ce4+ redox pair, promoting electron mobility and Ti‐Ce interactions. Optical and electronic spectroscopy reveals that Ce loading reduces the bandgap from 3.20 to 2.74 eV, extending light absorption into the visible range, thus enhancing the photocatalytic activity. The best sample, CeTNOh0.35, achieved 83% degradation of ciprofloxacin after 360 minutes under solar irradiation, with poor adsorption in the dark period. Higher Ce loadings negatively affect photoactivity by partially covering titania active sites. Reusability tests confirm the stability and efficiency of CeTNOh0.35 over three cycles, highlighting the importance of octahedral morphology in Ce‐containing systems to boost the final photoactivity for water remediation.

Nickel-Catalyzed Secondary Benzylic C-O Bond Borylation.

A remote steric hindrance ligand (m-tBu)2C6H3PCy2 (L1) was synthesized to promote Ni-catalyzed C-O bond activation. The reaction achieved high yields for secondary benzylic C(sp3)-O borylation in non-π-extended systems under mild conditions. Mechanistic studies indicate that the nickel complex containing 1 equiv of L1 serves as the active catalyst, while increased loading of L1 gives the inactive bisligated Ni species. Acetanilide is crucial for the cross-coupling reaction, which facilitates generation of the monoligated nickel species.

The Stability of UV-Defluorination-Driven Crosslinked Carbon Nanotubes: A Raman Study.

Carbon nanotubes (CNTs) are often regarded as semi-rigid, all-carbon polymers. However, unlike conventional polymers that can form 3D networks such as hydrogels or elastomers through crosslinking in solution, CNTs have long been considered non-crosslinkable under mild conditions. This perception changed with our recent discovery of UV-defluorination-driven direct crosslinking of CNTs in solution. In this study, we further investigate the thermal stability of UV-defluorination-driven crosslinked CNTs, revealing that they are metastable and decompose more readily than either pristine or fluorinated CNTs under Raman laser irradiation. Using Raman spectroscopy under controlled laser power, we examined both single-walled and multi-walled fluorinated CNTs. The results demonstrate that UV-defluorinated CNTs exhibit reduced thermal stability compared to their pristine or untreated fluorinated counterparts. This instability is attributed to the strain on the intertube crosslinking bonds resulting from the curved carbon lattice of the linked CNTs. The metallic CNTs in the crosslinked CNT networks decompose and revert to their pristine state more readily than the semiconducting ones. The inherent instability of crosslinked CNTs leads to combustion at temperatures approximately 100 °C lower than those required for non-crosslinked fluorinated CNTs. This property positions crosslinked CNTs as promising candidates for applications where mechanically robust, lightweight materials are needed, along with feasible post-use removal options.

Exploring the Nonenzymatic Origin of Duclauxin-like Natural Products.

Chemical-biological efforts to increase the diversity of duclauxin (1)-like molecules for medicinal chemistry purposes unveiled the reactivity of duclauxin (1) toward amines and alcohols. To expand the compound class, a semisynthetic strategy conjugating amines to duclauxin (1) was employed. Insights gained from this approach led to the hypothesis that certain duclauxin-like "natural products" such as talaromycesone B (2), bacillisporin G (3), xenoclauxin (4), bacillisporins F (5/6), bacillisporins J (8/9), bacillisporins I (12/13), and verruculosin A (38) may be isolation artifacts rather than enzymatic products. Further experimentation, involving adsorption of 1 onto silica gel, resulted in the production of 2-6. To gain insights into the conditions that generate such molecules, one-step reactions under mild conditions were set. Outcomes from both experiments confirmed that duclauxin-like molecules are generated via nonenzymatic reactions. This article presents analytical evidence, indicating that these molecules originate from 1, with the epimeric mixture of bacillisporins J (8 and 9) acting as the primary intermediate.

Construction of Six-Membered Lactam and Lactone Structures via Ligand-Free Pd-Catalyzed C-H Activation/[5 + 1] Cyclization Carbonylation.

An approach for the ligand-free Pd-catalyzed C-H activation/[5 + 1] cyclization carbonylation by employing readily available ClCF2COONa as a carbonyl source via difluorocarbene transfer and hydrolysis has been developed. The current protocol enables us to obtain a series of carbonylation cyclization product benzopyranone and phenanthridinone derivatives in up to 91% yield with excellent functional group compatibility. This protocol has the advantages of mild reaction conditions, wide applicable substrates, and simple and safe operation and provides a new method for the synthesis of complex lactam and lactone compounds.

Suppression of efficiency roll-off in solution-processed OLEDs using pyrimidine-based iridium complexes modified with sterically hindered groups

Three bis-cyclometalated iridium complexes Ir1-Ir3 were successfully synthesized through mild reaction conditions. All complexes exhibit emission peaks at 507-509 nm, with excellent photoluminescence quantum efficiencies (PLQY) ranging from 69% to 97%. Self-quenching is significantly reduced because the steric spacers lead to minimum bimolecular interactions. Accordingly, the electroluminescence device based on complex Ir3 exhibits a maximum luminous efficiency of 39.6 cd A−1, a high EQE of 13.1% with an efficiency roll-off of 4.2% at 1000 cd m−2, which is much smaller than that (10.8%) of the Ir1-based device. Moreover, its devices exhibit excellent stability even at elevated doping concentrations, suggesting a notable reduction in intermolecular interactions caused by the steric pinene spacer.

A New Route for the Synthesis of Trichloromethyl-1H-Benzo[d]imidazole and (1,2,3- Triazol)-1H-Benzo[d]imidazole Derivatives via Copper-Catalyzed N-Arylation and Huisgen Reactions

Abstract: In this study, functionalized 2-(trichloromethyl)-1H-benzo[d]imidazole derivative with good yields was synthesized using a copper-catalyzed N-arylation reaction of 2-iodoaniline and trichloroacetonitrile. This reaction was performed by employing the catalytic value of copper (I) and 1,10-phenanthroline as the ligand in tetrahydrofuran solvent at 23°C. In the following, the reaction of the final product with phenylacetylene and sodium azide (Huisgen reaction) using the copper catalyst in water solvent at 23°C led to the synthesis of new (1,2,3-triazol)-1H-benzo[d]imidazole derivatives with the principles of green chemistry and suitable efficiency. The availability of raw materials and suitable catalysts, mild reaction conditions, and easy purification are among the advantages of this method for the synthesis of various multi-substituted benzo[d]imidazole and 1,2,3-triazole derivatives.

Association between Mild Overweight and Survival: A Study of an Exceptionally Long-Lived Population in the Sardinian Blue Zone.

Background/Objectives: Overweight and obesity are generally considered risk factors for premature mortality. However, scientific evidence suggests that among older populations, mild conditions of overweight might be associated with reduced comorbidity and longer survival. This study investigates the potential association between anthropometric parameters and survival among a cohort of nonagenarians in Sardinia, Italy. Methods: This study included 200 subjects (50% females) aged 89 and older, enrolled in 2018 in the Sardinian Blue Zone-a population known for longevity-and followed for up to six years. Anthropometric variables such as body height, weight, age, sex, comorbidity, disability, and food group intake were collected using validated questionnaires and analyzed through multivariable analysis. Results: Out of 200 participants at baseline, 28 (14%) were still alive after six years of follow-up (females 10%, males 18%). Mean survival was 3.36 years (range 0.1-6.9 years) for males and 3.03 years (range 0.2-6.6 years) for females. Participants with a Body Mass Index (BMI) in the range of 25.0-27.0 kg/m2 among males and 25.0-27.2 kg/m2 among females had longer survival compared to those who were underweight (p = 0.002) or obese (p < 0.0001). The Cox proportional hazards regression model, adjusted for age, sex, and comorbidity, revealed a statistically significant association between the BMI and survival, demonstrating an inverted-U relationship. This indicates that mild overweight was associated with a survival advantage compared to both normal weight and obesity. Conclusions: Our study indicates that mild, but not severe, overweight in nonagenarians is associated with extended lifespan. Therefore, primary care physicians and geriatricians should exercise caution before recommending calorie-restricted diets for mildly overweight elderly patients.

TMSOTf‐Catalyzed Annulation of Ynamides with Alkynyl Sulfoxides to Construct Substituted Maleimides

A TMSOTf‐catalyzed annulation was developed for the construction of polysubstituted maleimides from ynamides and alkynyl sulfoxides, using oxygen as a green oxidant and ynamides as both carbon and nitrogen sources. This novel protocol proceeds in the presence of TMSOTf without the need for an expensive catalytic system and tolerates a broad substrate scope, providing a variety of maleimides in generally moderate to good yields under mild reaction conditions.

Long-lived carriers-promoted photocatalytic deuteration of halides with D2O as the deuterium source over Cu doped quantum dots

Deuterium labeling is a highly valuable yet challenging subject of research in various scientific fields. Conventional deuteration methods often involve harsh reaction conditions and suffer from limited reactivity and selectivity. Herein, we report a visible light–driven C–X (X = halogen) to C–D (D = deuterium) exchange strategy over copper-doped cadmium sulfide quantum dots (Cu-CdS QDs) under mild conditions, eliminating the need for noble metal catalysts and expensive deuterium sources. The conversion of aryl halides into deuterated products using Cu-CdS QDs reaches up to 99%, which is four times higher than that achieved using pristine CdS QDs. The substantial enhancement in the photocatalytic activity of the QDs can be primarily attributed to the generation of long-lived charge carriers (approximately 6 μs) induced by Cu doping. Mechanistic studies reveal that the Cu dopants considerably retard the recombination of photoinduced carriers by creating intermediate energy levels that serve as hole trapping centers in CdS QDs, thereby improving the electron utilization efficiency in energetically demanding photoreduction reactions. Additionally, the introduction of Cu increases the energy offset between the conduction band of CdS QDs and molecular acceptors, facilitating the electron transfer process. Upon visible light irradiation, a series of aryl halides can be efficiently converted into the desired deuterated compounds using D2O as the deuterium source. This work demonstrates that regulating charge carrier dynamics in ultrasmall QD-based photocatalysts is a promising strategy for promoting organic transformations.

Facile Synthesis of Potassium Decahydrido‐Monocarba‐closo‐Decaborate Imidazole Complex Electrolyte for All‐Solid‐State Potassium Metal Batteries

All‐solid‐state potassium metal batteries have caught increasing interest owing to their abundance, cost‐effectiveness, and high energy/power density. However, their development is generally constrained by the lack of suitable solid‐state electrolytes. Herein, we report a new complex KCB9H10·2C3H4N2, synthesized by grinding and heating the mixture of potassium decahydrido‐monocarba‐closo‐decaborate (KCB9H10) and imidazole (C3H4N2) under mild conditions, to achieve the K‐ion superionic solid‐state electrolyte. The crystal structure was revealed as an orthorhombic lattice with the space group of Pna21 by FOX software. The diffusion properties for K+ in the crystal structure were calculated using the climbing image nudged elastic band (CI‐NEB) method. KCB9H10·2C3H4N2 exhibited a high ionic conductivity of 1.3 × 10−4 S cm−1 at 30 °C, four orders of magnitude higher than that of KCB9H10. This ionic conductivity is also the highest value of hydridoborate‐based K+ conductors reported. Moreover, KCB9H10·2C3H4N2 demonstrated a K+ transference number of 0.96, an electrochemical stability window of 1.2 to 3.2 V vs. K/K+, and good stability against the K metal coated by a layer of potassium imidazolate (KIm). These great performances make KCB9H10·2C3H4N2 a promising K‐ion solid‐state electrolyte.

Asymptotic properties of conditional value-at-risk estimate for asymptotic negatively associated samples

This article examines the strong consistency of the conditional value-at-risk (CVaR) estimate for asymptotic negatively associated (ANA or ρ−\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$\\rho ^{-}$\\end{document}, for short) random samples under mild conditions. It is demonstrated that the optimal rate can achieve nearly O(n−1/2)\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$O (n^{-1/2})$\\end{document} under certain appropriate conditions. Furthermore, we present numerical simulations and a real data example to corroborate our theoretical results based on finite samples.

Novel Methods for the Formation of Free Carbyne Radicals in Solution.

Carbyne free radicals RC⋮ (RC) are usually associated with high-energy processes, thus research on their preparation, chemical reactivity, and prevalence under mild conditions is scarce. Recently, it was reported that metallo-complexes containing CR ligands may undergo spontaneous degradation in aqueous solutions to produce free RC radicals. These highly reactive species may react with each other to form the corresponding alkyne and other products. The reaction of 1,1,1 halo-carbo-hydrates with Cr(II) ions also forms RC radicals under mild conditions. Herein, we report two additional synthetic routes that produce free RC radicals under mild conditions. First, the reaction between metallic zinc and acetic anhydride produces 2-butyne and several other C2, C3, and C4 compounds. Isotopic-labeling experiments indicate that the formation of 2-butyne results from an inter-molecular reaction in which two RC moieties from two acetic anhydride molecules combine in solution. In addition, the degradation of the tri-molybdenum complex [Mo3(H3CC≡CCH3)(OAc)(H2O)2Br7], in which a 2-butyne ligand is coordinated to the Mo3 framework in a μ3-η2 (⊥) binding mode in aqueous solution produces several C2, C3, C4 and C5 molecules. This indicates the formation of free CH3C radicals by a homolytic cleavage of the carbon-carbon triple bond.

Organic Photoredox-Catalyzed Site-Selective Alkylation of Glycine Derivatives and Peptides via Infrequent 1,2-Hydrogen Atom Transfer of Amidyl Radicals.

Herein, we disclose a visible-light-driven photoredox-catalyzed protocol for site-selective alkylation of glycine derivatives via 1,2-hydrogen atom transfer, which is distinguished by metal free and mild conditions, high chemoselectivity, and good functional group compatibility. This protocol provides a unique approach for synthesizing valuable α,β-diamino acid derivatives. Furthermore, the potential synthetic merit of this transformation is proven by a scale-up reaction and late-stage functionalization of peptides.

Nickel-based perovskite-catalysed direct phenol-to-aniline liquid-phase transformations.

Liquid phase direct amination of phenols to primary anilines with hydrazine was achieved using commercial NiLa-perovskite catalysts as bifunctional Lewis acid/redox-active catalysts without adding any external hydride sources. The amination strategy took place efficiently in the absence of any amount of reducing gasses (H2/NH3) and noble metals under mild conditions.