Silver Complex Bearing N-Heterocyclic Carbene Bidentate Chelating Ligand as an Efficient Catalyst in Solvent-Free KA2 Coupling.

We report a synthesis of silver complexes bearing chelating bidentate N-heterocyclic carbene, with various substitutions at the terminal positions of the imidazole moiety of the NHC units. The long aliphatic substituents proved to be beneficial in terms of the synthetic efficiency of the complexes, compared to previously reported methyl substitution. The complexes demonstrated excellent suitability for the KA2 coupling reaction, providing quaternary carbon-containing propargylic amines in yields up to 95%, under solvent-free conditions. The method showed high tolerance for a wide range of substrates, including naturally occurring ketones, underscoring its practicality. To our knowledge, this represents the first use of a well-defined silver species in KA2 coupling, marking an advancement in the field.

Investigating the impact of wet rendering (solventless method) on PUFA-rich oil from catfish (Clarias magur) viscera.

Catfish (Clarias magur) is a popular freshwater fish food worldwide. The processing of this fish generates a significant amount of waste, mainly in the form of viscera, which constitutes around 10-12% of the fish's total weight. This study was focused on extracting polyunsaturated fatty acid (PUFA)-rich oil from catfish viscera, aiming to enhance the extraction process and make the production of oil and handling of fish byproducts more cost-effective. The wet reduction method, a solvent-free approach, was used for extraction, with yield optimization done via the Box-Behnken design. The resulting oil was evaluated for its oxidative quality and chemical characteristics. The optimal conditions for the wet rendering process were as follows: viscera to water ratio, 1:0.5 (w/v); temperature, 90℃; and time, 20 min, yielding 12.40 g/100 g of oil. The oil extracted under optimal wet rendering conditions had quality and oxidative stability comparable to solvent extraction and fewer secondary oxidation compounds. This oil had a higher PUFA content, specifically a 4:1 ratio of omega 6 to omega 3. Such oil, derived from catfish viscera, is suitable for the food industry due to its solvent-free extraction method.

The synthesis of 1,2,3-triazoles as binders of D-dopachrome tautomerase (D-DT) for the development of dual-targeting inhibitors.

Despite recent advances in the treatment of cancer, the issue of therapy resistance remains one of the most significant challenges in the field. In this context, signaling molecules, such as cytokines have emerged as promising targets for drug discovery. Examples of cytokines include macrophage migration inhibitory factor (MIF) and its closely related analogue D-dopachrome tautomerase (D-DT). In this study we aim to develop a new chemical class of D-DT binders and subsequently create a dual-targeted inhibitor that can potentially trigger D-DT degradation via the Proteolysis Targeting Chimera (PROTAC) technology. Here we describe the synthesis of a novel library of 1,2,3-triazoles targeting D-DT. The most potent derivative 19c (IC50 of 0.5 ± 0.04 µM with high selectivity toward D-DT) was attached to a cereblon (CRBN) ligand through aliphatic amides, which were synthesized by a remarkably convenient and effective solvent-free reaction. Enzyme inhibition experiments led to the discovery of the compound 10d, which exhibited moderate inhibitory potency (IC50 of 5.9 ± 0.7 µM), but unfortunately demonstrated no activity in D-DT degradation experiments. In conclusion, this study offers valuable insight into the SAR of D-DT inhibition, paving the way for the development of novel molecules as tools to study D-DT functions in tumor proliferation and, ultimately, new therapeutics for cancer treatment.

Solvent-Free Enzymatic Synthesis of Ethyl 3-Oxobutyrate Derivative: Characterization and Optimization of Reaction Condition.

It was first found that porcine pancreatic lipase (PPL) could catalyze the Knoevenagel condensation of aromatic aldehydes and ethyl acetoacetate under solvent-free conditions in this paper. Under solvent-free conditions, the highest yield of PPL catalytic reaction was 99.38%, and the Z/E selectivity of the product was 3.93. In addition, the reaction conditions were optimized, and the factors affecting the product structure were studied.

Large-Area Transparent Antimony-Based Perovskite Glass for High-Resolution X-ray Imaging.

Nonlead low-dimensional halide perovskites attract considerable attention as X-ray scintillators. However, most scintillation screens exhibit pronounced light scattering, which detrimentally reduces the quality of X-ray imaging. Herein, we employed a simple and straightforward solvent-free melt-quenching method to fabricate a large-area zero-dimension (0D) antimony-based perovskite transparent medium, namely (C20H20P)2SbCl5 (C20H20P+ = ethyltriphenylphosphine). The transparency is due to the large steric hindrance of C20H20P+, which hinders the formation of crystals during the quenching process, thus forming a glass with low refractive index and uniform structure. This medium exhibits a high transmittance exceeding 80% in the range of 450-800 nm and shows a large Stokes shift of 245 nm, thereby minimizing light scattering, mitigating self-absorption, and enhancing the clarity of X-ray imaging. Moreover, it exhibits a high radioluminescence light yield of ∼12,535 photons MeV-1 and displays a high X-ray spatial resolution of 30 lp mm-1 owing to its high transparency. This study presents an alternative candidate for achieving high-quality X-ray detection and extends the applicability of transparent perovskite scintillators.

Cobalt-Imidazole Complexes: Effect of Anion Nature on Thermochemical Properties.

A solvent-free method was proposed for the synthesis of hexaimidazolecobalt(II) nitrate and perchlorate complexes-[Co(C3H4N2)6](NO3)2 and [Co(C3H4N2)6](ClO4)2-by adding cobalt salts to melted imidazole. The composition, charge state of the metal, and the structure of the resulting complexes were confirmed by elemental analysis, XPS, IR spectroscopy, and XRD. The study of the thermochemical properties of the synthesized complexes showed that [Co(C3H4N2)6](NO3)2 and [Co(C3H4N2)6](ClO4)2 are thermally stable up to 150 and 170 °C, respectively. When the critical temperature of thermal decomposition is reached, oxidative two-stage gasification is observed. In this case, the organic component of the [Co(C3H4N2)6](NO3)2 complex undergoes almost complete gasification to form Co3O4 with a slight admixture of CoO, which makes it attractive as a component of gas-generation compositions, like airbags.

Tuning Coordination in ZIF-67 Through the Solid-State Thermal Synthesis for Balancing Structural Stability and Catalytic Reactivity.

Tailor-made unsaturated coordination of metal ions or organic linkers in zeolitic imidazole frameworks (ZIFs) has great potential in tuning the ZIFs' properties and reactivity for their applications. Taking advantage of the solid-state thermal (SST) method as a facile and eco-friendly synthesis method, the rational coordination of metal ions with imidazole ligands in ZIF-67 through the SST method is investigated. The rational precursor ratio (metal-to-ligand source) under the solvent-free SST method emerges as a perfect strategy to tune the coordinately unsaturated sites within the ZIF-67 frameworks. Different analysis techniques, computational methods (DFT), and catalytic model reactions examine unsaturated coordination in ZIF-67 materials (defect structures). The unsaturated coordination provides unique characteristic properties on materials with excellent catalytic performance. However, the higher reactive properties are negotiated with weaker structural stability on materials. In addition, the post-SST approach is applied to enable rational coordination and modify the pristine ZIF-67 materials. The post-SST method rearranges and modifies coordination in the framework of materials. These findings are crucial to understanding the role of the uncoordinated degree to balance with structural stability based on ZIF-67, which is critical for effective heterogeneous catalysts.

Solvent-Free and UV-Cured Epoxy Silicone Coating with Excellent Wear Resistance and Antismudge Properties.

Transparent, hard, and flexible multifunctional coatings have a wide range of applications; however, most of them need organic solvents. Here, we present a solvent-free and UV-cured coating made from fluorinated epoxy MTQ silicone resin combined with branched triepoxy siloxane as the reactive diluent. After UV-initiated ring-opening polymerization in the presence of a triarylsulfonium hexafluoroantimonate catalyst, the resultant cured coating exhibits high transparency (∼92%, 550 nm), pencil hardness (7H), and flexibility (1 mm bending diameter) due to the formed organic-inorganic nanostructures in a highly cross-linked network. The triepoxy siloxane significantly reduces the viscosity before curing and increases cross-link density of the coating. The coating without any volatile content shows a smooth surface with low roughness (Rq = 0.46 nm) and delivers an anti-smudge ability owing to perfluorinated chains inherited from the MTQ resin. Furthermore, even after 3000 abrasion cycles, the coating still has a water contact angle greater than 90°, displaying excellent wear resistance. Our work provides a promising way to access high-performance multifunctional coatings in a more sustainable manner.

Evaluation of antibacterial, cytotoxicity, and apoptosis activity of novel chromene-sulfonamide hybrids synthesized under solvent-free conditions and 3D-QSAR modeling studies.

In this study, eleven novel chromene sulfonamide hybrids were synthesized by a convenient method in accordance with green chemistry. At first, chromene derivatives (1-9a) were prepared through the multi-component reaction between aryl aldehydes, malononitrile, and 3-aminophenol. Then, synthesized chromenes were reacted with appropriate sulfonyl chlorides by grinding method to give the corresponding chromene sulfonamide hybrids (1-11b). Synthesized hybrids were obtained in good to high yield and characterized by IR, 1HNMR, 13CNMR, CHN and melting point techniques. In addition, the broth microdilution assay was used to determine the minimal inhibitory concentration of newly synthesized chromene-sulfonamide hybrids. The MTT test was used to determine the cytotoxicity and apoptotic activity of the newly synthesized compounds against fibroblast L929 cells. The 3D­QSAR analysis confirmed the experimental assays, demonstrating that our predictive model is useful for developing new antibacterial inhibitors. Consequently, molecular docking studies were performed to validate the findings of the 3D-QSAR analysis, confirming the potential binding interactions of the synthesized chromene-sulfonamide hybrids with the target enzymes. Molecular docking studies were employed to support the 3D-QSAR predictions, providing insights into the binding interactions between the newly synthesized chromene-sulfonamide hybrids and their target bacterial enzymes, thereby reinforcing the potential efficacy of these compounds as antibacterial agents. Also, some of the experimental outcomes supported or conflicted with the pharmacokinetic prediction (especially about compound carcinogenicity). The performance of ADMET predictor results was assessed. The work presented here proposes a computationally driven strategy for designing and discovering a new sulfonamide scaffold for bacterial inhibition.

Mechanochemical Synthesis of Silylcyclopentenes via Ball Milling.

The development of innovative methods for synthesizing silylcyclopentene compounds is particularly important for enriching and improving the synthetical toolbox of organosilicon compounds. Herein, a facile approach has been developed for the synthesis of silylcyclopentenes promoted by mechanochemically generated organolithium species as silicon nucleophiles under ball milling conditions, avoiding the requirement of large amounts of bulk solvent. This operationally simple method demonstrates good functional group compatibility, which provides a great opportunity for further exploration of the synthetic applications of silylcyclopentenes. Density functional theory calculations indicated that the transient lithiosilole intermediates undergo a stepwise nucleophilic addition process, which governs this mechanic-force-promoted [4+1] cycloaddition reaction.

Solvent-Free Synthesis Enables Encapsulation of Subnanometric FeOx Clusters in Pure Siliceous Zeolites for Efficient Catalytic Oxidation Reactions.

Metal/metal oxide clusters possess a higher count of unsaturated coordination sites than nanoparticles, providing multiatomic sites that single atoms do not. Encapsulating metal/metal oxide clusters within zeolites is a promising approach for synthesizing and stabilizing these clusters. The unique feature endows the metal clusters with an exceptional catalytic performance in a broad range of catalytic reactions. However, the encapsulation of stable FeOx clusters in zeolite is still challenging, which limits the application of zeolite-encapsulated FeOx clusters in catalysis. Herein, we design a modified solvent-free method to encapsulate FeOx clusters in pure siliceous MFI zeolites (Fe@MFI). It is revealed that the 0.3-0.4 nm subnanometric FeOx clusters are stably encapsulated in the 5/6-membered rings intersectional voids of the pure siliceous MFI zeolites. The encapsulated Fe@MFI catalyst with a Fe loading of 1.4 wt % demonstrates remarkable catalytic activity and recycle stability in the direct oxidation of methane, while also promoting the direct oxidation of cyclohexane, surpassing the performance of conventional zeolite-supported Fe catalysts.

Bimetallic MnZn-MOF-74 with enhanced percentage of MnIII: Efficiently catalytic activity for direct oxidative carboxylation of olefins to cyclic carbonates under mild and solvent-free condition.

Multi-functional MOF catalyst with oxidative- and acid- centers showed potential in olefins oxidative carboxylation to cyclic carbonates directly. In this work, a series of bimetallic MnZn-MOF-74 with different molar ratios of Mn and Zn were synthesized successfully through a one-pot facile method. Thoroughly characterization indicated that the existence of Zn regulated the valance state distribution of Mn in the obtained MnZn-MOF-74. Mn99.3Zn0.7-MOF-74 with the highest ratio of MnIII (61.3 %) performed the most efficient activity for olefin direct tandem oxidative carboxylation reaction using aqueous tert-butyl hydroperoxide oxidant under solvent-free condition of 90 °C, 1.0 MPa CO2 and 4 h. Mn99.3Zn0.7-MOF-74 also showed satisfactory versatility and recyclability. Based on the experiments, a feasible mechanism was presented. Thanks to the high ratio of active MnIII as main oxidative center, the coordination unsaturated bimetal Mn and Zn as Lewis-acid sites, O2- of metal - O as Lewis-base sites and combined effect with Bu4NBr cocatalyst, Mn99.3Zn0.7-MOF-74 presented efficient performance for the direct synthesis of cyclic carbonates from olefins. The metal Zn in MOF can regulate the valance state distribution of Mn and result in efficient catalytic property, presenting a potential avenue for direct oxidative carboxylation reaction of olefins to cyclic carbonates synthesis.

Development of a NiFe2O4 covalent organic framework based magnetic solid-phase extraction approach for specific capture of quinolones in animal innards prior to UHPLC-Q-Orbitrap HRMS detection.

This study aimed to present a selective and effective method for analyzing quinolones (QNs) in food matrix. Herein, a NiFe2O4-based magnetic sodium disulfonate covalent organic framework (NiFe2O4/COF) was prepared using a simple solvent-free grinding method, and was adopted as a selective adsorbent for magnetic solid phase extraction of QNs. Coupled with UHPLC-Q-Orbitrap HRMS, an efficient method for simultaneous detection of 18 kinds of QNs was established. The method exhibited good linearity (0.01-100 ng g-1), high sensitivity (LODs ranging from 0.0011 to 0.0652 ng g-1) and precision (RSDs below 9.5%). Successful extraction of QNs from liver and kidney samples was achieved with satisfactory recoveries ranging from 82.2% to 108.4%. The abundant sulfonate functional groups on NiFe2O4/COF facilitated strong affinity to QNs through electrostatic and hydrogen bonding interactions. The proposed method provides a new idea for the extraction of contaminants with target selectivity.

Solvent Free Potassium 3,5-dinitro-6-oxo-1,6-dihydropyrazin-2-olate 3D EMOF as Thermally Stable Energetic Material.

Heat-resistant explosives play a vital role in indispensable applications. For this, we have synthesized a novel, three-dimensional, solvent-free energetic metal-organic framework (EMOF) potassium 3,5-dinitro-6-oxo-1,6-dihydropyrazin-2-olate (KDNODP) straightforwardly. The synthesized EMOF was characterized through IR, NMR spectroscopy, elemental analysis, and differential scanning calorimetry studies. Furthermore, single-crystal X-ray diffraction provided a complete description of KDNODP. It exhibits a three-dimensional EMOF structure with remarkably balanced properties such as high density (2.11 g cm-3), excellent thermal stability (291 °C), good detonation performance (8127 m s-1 and 26.94 GPa) and low mechanical sensitivity (IS=35 J; FS=360 N) than the commonly used heat-resistant explosives HNS (density=1.74 g cm-3; VOD=7164 m s-1, DP=21.65 GPa, IS=5 J) as well as the similar reported energetic potassium MOFs. To gain insights into the packing and intermolecular interactions, the Hirshfeld surface and a 2D fingerprint analysis were examined. Additionally, scanning electron microscopy was used to investigate the particle size and morphological characteristics of KDNODP. These outcomes highlight a successful method for creating 3D EMOF based on a six-membered heterocycle as a potential heat-resistant energetic material.

Fusion Bonding Technique for Solvent-Free Fabrication of All-Solid-State Battery with Ultrathin Sulfide Electrolyte.

For preparing next-generation sulfide all-solid-state batteries (ASSBs), the solvent-free manufacturing process has huge potential for the advantages of economic, thick electrode, and avoidance of organic solvents. However, the dominating solvent-free process is based on the fibrillation of polytetrafluoroethylene, suffering from poor mechanical property and electrochemical instability. Herein, a continuously solvent-free paradigm of fusion bonding technique is developed. A percolation network of thermoplastic polyamide (TPA) binder with low viscosity in viscous state is constructed with Li6PS5Cl (LPSC) by thermocompression (≤5 MPa), facilitating the formation of ultrathin LPSC film (≤25 µm). This composite sulfide film (CSF) exhibits excellent mechanical properties, ionic conductivity (2.1 mS cm-1), and unique stress-dissipation to promote interface stabilization. Thick LiNi0.83Co0.11Mn0.06O2 cathode can be prepared by this solvent-free method and tightly adhered to CSF by interfacial fusion of TPA for integrated battery. This integrated ASSB shows high-energy-density feasibility (>2.5 mAh cm-2 after 1400 cycles of 9200 h and run for more than 10 000 h), and energy density of 390 Wh kg-1 and 1020 Wh L-1. More specially, high-voltage bipolar cell (≥8.5 V) and bulk-type pouch cell (326 Wh kg-1) are facilely assembled with good cycling performance. This work inspires commercialization of ASSBs by a solvent-free method and provides beneficial guiding for stable batteries.

Solvent-free synthesis of defective Zr-based metal-organic framework from waste plastic bottles for highly efficient lomefloxacin removal.

Large amount of polyethylene terephthalate (PET) plastics waster and emerging contaminants in water, including fluoroquinolone antibiotics, pose challenges to human survival. In this work, a green synthesis scheme is proposed in which the defective UiO-66 (d-UiO-66) is fabricated via a solvent-free routine by using PET plastics waster as raw materials for lomefloxacin (LOM) removal. In comparison with defect-free UiO-66, the created defect imparts d-UiO-66 with higher porosity and abundant defective Zr sites, which are beneficial to boost LOM adsorption. As expected, d-UiO-66 exhibited excellent LOM adsorption performances, showcasing a saturation adsorption capacity of 588 mg g-1 and a kinetic rate constant of 0.204 g mg-1 h-1, which are 3.5 and 2.0 times higher than those of the pristine UiO-66, respectively. Remarkably, the LOM saturation adsorption capacity of d-UiO-66 surpasses that of all reported adsorbents. Mechanism study reveals that this outstanding adsorption performance of d-UiO-66 is mainly ascribed to the abundant defective sites, high porosity, together with the strong hydrogen bonding interaction and π-π stacking interaction between d-UiO-66 and LOM. Therefore, the d-UiO-66 obtained by the solvent-free method can not only effectively upcycle PET plastic waster, but also efficiently remove LOM, demonstrating a potential routine to simultaneous address the solid PET waster and wastewater.

Lipase-catalyzed solvent-free synthesis of monoglycerides from biodiesel-derived crude glycerol: Optimized using response surface methodology.

The growth of the biodiesel industry has resulted in significant quantity of crude glycerol. It is necessary to explore the synthesis of high-value-added products from crude glycerol. In this study, the enzymatic synthesis of monoglycerides under solvent-free conditions, employing crude glycerol as the primary feedstock, had been investigated. The analysis showed that the highest yield of monoglycerides was obtained after 12 h, and Novozym 435 showed the highest monoglyceride yield of 18.41 % among the three lipases tested, followed by Lipozyme TL IM and Lipozyme RM IM. Monoglycerides were synthesized from biodiesel-derived crude glycerol using Novozym 435 as the catalyst under solvent-free conditions at different parameters, which were catalyst concentration, substrate molar ratio, and temperature. The yield of monoglycerides was examined in single-factor experiments. Response surface methodology (RSM) was subsequently employed to optimize the synthesis conditions based on the single-factor experimental results. The optimal conditions were at an enzyme concentration of 12.7 wt% and a molar ratio of crude glycerol:oil of 5.7:1 at a reaction temperature of 65.2 °C. The experimental yield of monoglycerides under the optimal conditions was 28.93 %, which is close to the value predicted from the RSM model (29.02 %).

Van der Waals Magnetic Electrode Transfer for Two-Dimensional Spintronic Devices.

Two-dimensional (2D) materials are promising candidates for spintronic applications. Maintaining their atomically smooth interfaces during integration of ferromagnetic (FM) electrodes is crucial since conventional metal deposition tends to induce defects at the interfaces. Meanwhile, the difficulties in picking up FM metals with strong adhesion and in achieving conductance match between FM electrodes and spin transport channels make it challenging to fabricate high-quality 2D spintronic devices using metal transfer techniques. Here, we report a solvent-free magnetic electrode transfer technique that employs a graphene layer to assist in the transfer of FM metals. It also serves as part of the FM electrode after transfer for optimizing spin injection, which enables the realization of spin valves with excellent performance based on various 2D materials. In addition to two-terminal devices, we demonstrate that the technique is applicable for four-terminal spin valves with nonlocal geometry. Our results provide a promising future of realizing 2D spintronic applications using the developed magnetic electrode transfer technique.

Efficient Solvent-Free Synthesis of Indolizines Using CuBr Catalyst from Pyridine, Acetophenone, and Electron-Deficient Alkenes.

Herein, we have developed a new approach for the synthesis of indolizine via Cu-catalyzed reaction of pyridine, acetophenone, and nitroolefin under mild conditions in high yields. This reaction involved the formation of C-N and C-C bonds and new indolizine compounds with high stereoselectivity and excellent functional group tolerance.

A solvent-free squeezing method for extraction of collected mass from aerosols of electronic cigarettes and heated tobacco products.

Previous in vitro toxicological assessments have demonstrated that almost no mutagenic and genotoxic activities in electronic cigarette (e-cigarette) and heated tobacco product (HTP) aerosols were detected even at the maximum recommended concentration. To accurately compare the toxicity levels between cigarette smoke and e-cigarette or HTP aerosols, higher exposure concentrations increasing the possibility to detect toxicity in in vitro tests are necessary, while avoiding solvent-induced toxicity. This study aimed to develop a solvent-free extraction method to obtain concentrated aerosol extracts for improved toxicological evaluation. Our novel approach involved squeezing several Cambridge filter pads, which collected aerosol constituents, in closed containers to achieve solvent-free extraction with comparable efficiency to the conventional method using organic solvents. The optimized squeezing method yielded extracts with concentrations approximately 10 times higher than those obtained in conventional extraction methods. Yield comparison of various constituents, such as flavoring compounds, in e-cigarette aerosol extracts revealed similar extraction efficiencies between the squeezing and conventional methods. However, the extraction efficiency for constituents with high log Pow values, predominantly found in HTP aerosol extracts, was unacceptably low using the squeezing method. In addition, solvent-free centrifuging, another type of extraction method, exhibited unsatisfactory results for even e-cigarette aerosols compared with the conventional method. Our findings suggest that the solvent-free squeezing method is suitable for extracting aerosol collected mass from e-cigarette aerosol but not from HTP aerosol. We anticipate that the solvent-free squeezing method will contribute to a deeper understanding of toxicological differences between e-cigarettes and conventional combustible cigarettes.