A gold-catalyzed sulfonylation of aryl/vinyl iodides to synthesize aryl sulfones facilitated by the ligand-enabled Au(I)/Au(III) redox catalysis was developed. In the reaction, aryl sodium sulfinates or sulphinic acids can react smoothly with aryl/vinyl iodides to directly construct various aryl sulfones. The strong synthetic capabilities of sulfone synthesis are demonstrated by its easily available and handled reagents, good functional group compatibility, and late-stage application of complicated biomolecules.
View Article and Find Full Text PDFIn order to mitigate the release of toxic phosphine from aluminum hypophosphite in twin-screw processing, montmorillonite-melamine cyanurate was prepared by three methods: (1) mechanical intercalation, (2) water intercalation and (3) in situ intercalation. The sheet spacing of montmorillonite was increased from 1.140 nm to 1.
View Article and Find Full Text PDFA gold-catalyzed sulfonylation reaction of aryl iodides with different sodium sulfinates facilitated by the ligand-enabled Au(I)/Au(III) redox catalysis was developed. In the reaction of gold-catalyzed C-S coupling, a variety of functionalized sodium sulfinates, such as CF, CHF, CH, and alkyl groups, can react smoothly with aryl iodides to directly construct diversely functionalized aryl sulfones. This gold-catalyzed sulfonylation offers a complementary method for synthesizing functionalized aryl sulfones with electron-donating groups.
View Article and Find Full Text PDFCompared to the well-established transition metal-catalyzed cross-coupling reactions, Au(I)/Au(III)-catalyzed cross-coupling reactions have lagged behind. Despite some advancements, achieving gold-catalyzed C-O coupling with carboxylic acids via an Au(III) carboxylate intermediate remains challenging due to the thermal unfavorability of the critical reductive elimination step. Here, we present the first photosensitized reductive elimination of gold(III) to enable esterification of aryl iodides with carboxylic acids.
View Article and Find Full Text PDFPoly(urethane-urea) elastomers (PUUEs) have gained significant attention recently due to their growing demand in electronic skin, wearable electronic devices, and aerospace applications. The practical implementation of these elastomers necessitates many exceptional properties to ensure robust and safe utilization. However, achieving an optimal balance between high mechanical strength, good self-healing at moderate temperatures, and efficient flame retardancy for poly(urethane-urea) elastomers remains a formidable challenge.
View Article and Find Full Text PDFThe single-layer MXene fully demonstrates the advantages of 2D materials, especially catalytic, conductive, and mechanical properties. However, the high energy consumption and low efficiency faced by MXene in the divestiture process are still challenges that need to be solved urgently. In this article, dimension mismatch and collaborative stripping strategies are skillfully combined to easily realize the transformation from multi-layer MXene to single layer.
View Article and Find Full Text PDFACS Appl Mater Interfaces
July 2024
Sulfonated octaphenylsilsesquioxane (SPOSS) has garnered significant interest due to its unique structural properties of containing the -SOH group and its wide range of applications. This study introduces a novel approach to the synthesis of SPOSS, leveraging machine learning algorithms to explore new recipes and achieve higher -SOH functionality. The focus was on synthesizing SPOSS with 2, 4, 6, and 8-SOH functional groups on the phenyl group, marked as SPOSS-2, SPOSS-4, SPOSS-6, and SPOSS-8, respectively.
View Article and Find Full Text PDFSci Total Environ
October 2024
Globally, numerous freshwater lakes exist, and rapid urbanization has impacted carbon biogeochemical cycling at the interface where water meets air in these bodies. However, there is still a limited understanding of CO absorption/emission in eutrophic urbanizing lakes. This study therefore involved biweekly in-situ monitoring to evaluate fluctuations in the partial pressure (pCO) and flux (fCO) of CO and associated parameters from January to September 2020 (7:00-17:00 CST) in an urbanizing lake in southwestern China.
View Article and Find Full Text PDFAluminum hypophosphite (AHP) has been used as a flame retardant for a long time. Previous studies about AHP employed in flame retardant materials mostly focus on coating, modification, and complex system. It is valuable to explore simple experimental steps to prepare nano hybrids with AHP and metal-organic frameworks (MOFs).
View Article and Find Full Text PDFCyclomatrix polyphosphazenes have attracted widespread attention in the field of polymer flame retardancy. Nevertheless, the optimal manifestation of their distinctive structural attributes and flame-retardant properties necessitates a judicious selection of condensation monomers and synergistic templates during the fabrication of polyphosphazene flame retardants. In our previous studies, it was discovered that when ZIF-67 is functionalized with polyphosphazene, the by-product HCl from phosphazene polycondensation causes etching on ZIF-67.
View Article and Find Full Text PDFA gold-catalyzed C(sp)-C(sp) Suzuki-Miyaura coupling reaction facilitated by ligand-enabled Au(I)/Au(III) redox catalysis was developed. The cross-coupling of alkyl organometallics was first realized in the redox catalytic cycle in gold chemistry, without the use of external oxidants. This gold-catalyzed C(sp)-C(sp) coupling reaction allows a variety of alkyl chain and useful methyl trifluoroborates to react with aryl and vinyl iodides under very mild conditions, which provides a new reactivity pattern for challenging couplings with alkyl organometallics.
View Article and Find Full Text PDFBiobased-functionalized metal-organic frameworks (Bio-FUN-MOFs) stand out from the crowd of candidates in the flame-retardant field due to their multipathway flame-retardant mechanisms and green synthesis processes. However, exploring and designing Bio-FUN-MOFs tend to counteract the problem of compromising the flame-retardant advantages of MOFs themselves, which inevitably results in a waste of resources. Herein, a strategy in which MOFs are ecologically regulated through acid-base balance is presented for controllable preparation of Bio-FUN-MOFs by two birds with one stone, i.
View Article and Find Full Text PDFTo enhance char formation of flame retardant epoxy (EP) composites, carboxymethyl β-cyclodextrin (CM-β-CD) is employed as an etchant for or ZIF-67 derivatives. In the early stage, etching plays a dominant role. The mismatch in size between CM-β-CD opening and ZIF-67 pore leads to the stacking of carboxyl cobalt complexes on the shell.
View Article and Find Full Text PDFThe effects of octaphenylsilsesquioxane (OPS), fumed silica, and silica aerogel on the thermal insulation properties of ethylene propylene diene monomer (EPDM) rubber were studied. On this basis, two kinds of fillers with good performances were selected to study the thermal insulation of an EPDM full-formula system. The results show that the addition of fumed silica or silica aerogel had a positive effect on the thermal insulation performance of EPDM rubber and its composite.
View Article and Find Full Text PDFACS Appl Mater Interfaces
February 2024
Enhancing the performance of traditional pesticide formulations by improving their leaf surface wetting capabilities is a crucial approach for maximizing the pesticide efficiency. This study develops an emulsifiable concentrate (EC) of 4.5% β-cypermethrin containing oil (BJO).
View Article and Find Full Text PDFUp to now, metal-organic frameworks (MOFs) with open nanostructures have shown outstanding capabilities in trapping smoke particles compared to the original MOFs. However, only a few MOF-based strategies have been reported to synthesize hierarchical porous cages thus far, which are mainly restricted to environmentally unfriendly wet-chemical liquid methods. Herein, as a proof-of-concept, a gas-steamed metal-organic framework approach was designed to fabricate a series of cheeselike open cages with hierarchical porosity.
View Article and Find Full Text PDFThe traditional transition metal catalyzed neutral C(sp)-C(sp) cross-coupling reaction between a nucleophile and an electrophile is a key technique for the formation of carbon-carbon bonds. Herein, we present a general gold-catalyzed oxidative Sonogashira cross-coupling of arylboronic acids and terminal arylalkynes at room temperature with excellent functional-group tolerance and good chemoselectivity. Moreover, our mechanistic studies suggested a third pathway involving a base-assisted transmetalation between the gold(I) catalyst and aryl boronic acid might predominate in our reaction conditions, rather than the previously assumed oxidation of the gold(I) complex or deprotonation of alkynes.
View Article and Find Full Text PDFA dodecahedral superstructure consisting of a single layer of Janus spheres containing ZIF-67 nanodots is prepared by in situ polymerization, with ZIF-67 and bio-based phytic acid (PA) as templates and dopants. It is used to improve the flame retardant, electromagnetic (EMI) shielding, and thermal conductivity properties of polyurea (PUA). By adding 5 wt% polyaniline@cobalt phytate-2.
View Article and Find Full Text PDFParkinson's disease (PD) is a progressive neurodegenerative disorder causing the loss of dopaminergic neurons in the substantia nigra and the drastic depletion of dopamine (DA) in the striatum; thus, DA can act as a marker for PD diagnosis and therapeutic evaluation. However, detecting DA in the brain is not easy because of its low concentration and difficulty in sampling. In this work, we report the fabrication of a covalent organic framework (COF)-modified carbon fiber microelectrode (cCFE) that enables the real-time detection of DA in the mouse brain thanks to the outstanding antibiofouling and antichemical fouling ability, excellent analytical selectivity, and sensitivity offered by the COF modification.
View Article and Find Full Text PDFPolyurethane elastomer (PUE), which is widely used in coatings for construction, transportation, electronics, aerospace, and other fields, has excellent physical properties. However, polyurethane elastomers are flammable, which limits their daily use, so the flame retardancy of polyurethane elastomers is very important. Reactive flame retardants have the advantages of little influence on the physical properties of polymers and low tendency to migrate out.
View Article and Find Full Text PDFThe ladder phenyl/vinyl polysilsesquioxane (PhVPOSS) was used to improve the flame-retardancy performances of ethylene-vinyl acetate copolymer (EVA)/aluminum hydroxide (ATH) composites due to the reactivity of its vinyl groups. FTIR, XPS, H NMR, and SEM-EDS data demonstrated the PhVPOSS grafting onto EVA molecular chains. The PhVPOSS improved the thermal stability of EVA/ATH composites, as shown by the thermogravimetric analysis (TGA).
View Article and Find Full Text PDFAs synthetic fibers with superior performances, nylon 6 fibers are widely used in many fields. Due to the potential fire hazard caused by flammability, the study of the flame retardancy of nylon 6 fibers has been attracting more and more attention. The review has summarized the present research status of flame-retarded nylon 6 fibers from three aspects: intrinsic flame-retarded nylon 6, nylon 6 composites, and surface strategies of nylon 6 fibers/fabrics.
View Article and Find Full Text PDFThe crystal moisture sensitivity can be tuned by the chemical composition on the crystal surface. Ammonium dinitramide (ADN) crystal is a promising oxidizer for solid propellants. However, its strong moisture sensitivity greatly limits its practical applications.
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