Aryl Sulfides Research Articles

Green synthesis of cobalt oxide nanoparticles (Co3O4NPs): Characterization and green light-driven photocatalytic aerobic oxidation of alkyl and aryl sulfides to the corresponding sulfoxides

In recent years, cobalt oxide nanoparticles (Co3O4NPs) have garnered significant attention due to their unique properties and wide range of applications, particularly in catalysis and environmental remediation. This study focuses on the green synthesis of Co3O4NPs using garlic extract as a bio-reducing and stabilizing agent, marking the first instance of employing this eco-friendly and cost-effective method. The synthesized nanoparticles were characterized using various techniques including SEM, EDX, FTIR, XRD, UV–Vis DRS, and BET analysis, revealing their spherical morphology, elemental composition, surface area, and optical properties. The primary application investigated was the photocatalytic aerobic oxidation of alkyl and aryl sulfides to sulfoxides under visible green light irradiation. The study meticulously optimized the reaction conditions, evaluating the effects of different solvents, light sources, and catalyst dosages. The optimal conditions were found to be a MeCN:H2O (5:1) solvent system, green LED light (535 nm), and 10 mg of Co3O4NPs catalyst with the highest TON of 12.5. Under these conditions, the catalyst demonstrated high efficiency, achieving up to 95% yield of sulfoxides with various substrates. Furthermore, the reusability of the Co3O4NPs was assessed through multiple catalytic cycles, showing excellent stability and consistent performance. Mechanistic studies indicated that the photocatalytic activity involves the generation of reactive oxygen species (ROS) such as superoxide anion radicals (O2.-) and singlet oxygen (1O2), with both holes and electrons playing crucial roles in the oxidation process. This research highlights the potential of green synthesized Co3O4NPs as effective and sustainable photocatalysts for selective oxidation reactions, offering a promising approach for environmentally benign chemical processes. The findings pave the way for further exploration of bio-derived catalysts in various industrial applications, promoting greener and more sustainable practices in chemical synthesis.

Heterogenization of Homogeneous Donor-Acceptor Conjugated Polymers for Efficient Photooxidation: An Approach Toward Sustainable and Recyclable Photocatalysis.

Recovery of homogeneous photocatalysts from reaction mixture is challenging, affecting the cost-effectiveness, and masks their advantages, including 4-8 fold higher catalytic activity than corresponding heterogeneous counterparts. Incorporation of long alkyl chains within the rigid π-conjugated backbone of conjugated polymers can augment their solubility in particular organic solvents; accordingly, they can function as homogeneous photocatalysts. Consequently, these polymers facilitate the recovery of catalysts through the reverse dissolution process, thus creating a well-suited platform to meet certain advantages of both homo- and heterogeneous photocatalysts. This work exemplifies the unprecedented perks of donor-acceptor conjugated polymers from benzodithiophene and substituted dibenzothiophene sulfone moieties for their homogeneous phase photoredox activities along with their heterogeneous recovery and reuse up to five runs. The potential intermediate singlet oxygen (1O2) and superoxide (O2•-) as reactive oxygen species generated by these photostable conjugated polymers efficiently catalyze the visible-light-driven oxidation of aryl sulfides (up to 92% yield) and oxidative hydroxylation of phenylboronic acids (up to 93% yield), respectively. Therefore, to actualize the heightened catalytic performance and formulate a design strategy for polymeric photoredox catalyst, our work introduces an alternative approach to the advancement of photocatalysis with diverse catalytic activities.

Design, Synthesis, and Antifeedant Activity Evaluation of 13/14-Arylthioether Matrine Derivatives.

Introducing a sulfur atom into active agricultural molecules is an important strategy for pesticide development. Matrine, an environmentally friendly botanical pesticide, has the advantage of being easily degraded and has drawn attention in the agricultural field. To explore the novel matrine-type pesticides, in this study, we designed and synthesized 13/14-arylthioether matrine derivatives by introducing various aryl sulfide motifs into bioactive matrine. Most of the synthesized arylthioether matrines exhibited good antifeedant activity against Spodoptera exigua. Among them, compound 2q showed the best antifeedant effect with an EC50 value of 0.038 mg/mL, which is approximately 125-fold more activity than matrine and reached the activity level of commercial standard azadirachtin A. Furthermore, compound 2q exhibited an inhibitory effect on antifeedant-related enzyme carboxylesterase (CarE) from S. exigua. In short, the high activity of arylthioether matrines offers new insights into developing new antifeedants.

Oxidation-Responsive Supramolecular Hydrogels Based on Glucosamine Derivatives with an Aryl Sulfide Group.

Supramolecular hydrogels can be obtained via self-assembly of small molecules in aqueous environments. In this study, we describe the development of oxidation-responsive supramolecular hydrogels comprising glucosamine derivatives with an aryl sulfide group. We demonstrate that hydrogen peroxide can induce a gel-sol transition through the oxidation of the sulfide group to the corresponding sulfoxide. Furthermore, we show that this oxidation responsiveness can be extended to photo-responsiveness with the aid of a photosensitizer.

(Invited) Semiconductor Facet Effects Toward Photocatalysis

Photo-induced charge transfer has been found to strongly depend on the exposed semiconductor surfaces. For instance, {110}-bound Cu2O rhombic dodecahedra exhibit a high photocatalytic activity toward dye degradation, but {100}-terminated Cu2O cubes are inert. Photocatalytic behaviors of Cu2O-based semiconductor heterostructures, such as Cu2O-ZnS and Cu2O-ZnO composites, can both enhance and suppress photocatalytic activity depending on the contacting planes at the heterojunction. Significantly, Cu2O photocatalytic activity can be greatly enhanced by functionalizing with conjugated molecules such as 4-nitrophenylacetylene (4-NA) to tune the surface band structure. This can turn the inactive cubes to possess a superior photocatalytic activity. Recently, Cu2O rhombic dodecahedra with and without 4-NA modification have been employed in photocatalytic hydroxylation of boronic acids, aryl sulfide oxidation, and amine coupling. SrTiO3 truncated rhombic dodecahedra were also found to be effective in amine coupling. Oxidative cyclization of thioamides is the latest example of surface control to photocatalytic organic transformations.

Photocatalytic Functionalization of Alkenes Enabled by Polyfluoroaryl Migration

AbstractVisible light‐mediated photocatalytic approach for the radical functionalization of alkenes bearing the fluorinated aryl sulfide fragment is described. The process occurs in the presence of organic photocatalyst using sulfinates as sources of radicals. The key step of the reaction is the intramolecular 1,4‐migration of the polyfluoroaryl group. In the reaction, three new bonds are formed (two C−C and one C−S bond). The decisive role of fluorine atoms in the reaction efficiency was confirmed by DFT calculations.

A facile solvent activation process manipulates the structure and filtration performance of oxidized poly (arylene sulfide sulfone) TFC membrane

In this study, solvent-resistant polyamide (PA) thin film composite (TFC) nanofiltration (NF) membranes were successfully prepared based on an ultrasolvent-resistant oxidized poly (arylene sulfide sulfone) (O-PASS) substrate. The effects of different substrates on interfacial polymerization (IP) process were systematically studied. The O-PASS-TFC membranes were activated to different degrees by a controlled activation process using the mixture solvent of DMF/H2O with different ratio of DMF, the solubility power can be designed by adjusting DMF volume fraction, as the activation solvent. The membrane followed pure DMF treatment was found to have the excellent performance: the surface morphology of TFC membrane was activated to smooth and high negative charged, yield nanofiltration (NF) performance with a solution permeance of 8.82 LMH bar−1 (~621 % increase) and a pure water permeance (PWP) of 11.59 LMH bar−1 (~607 % increase), Na2SO4 rejection maintained above 98.7 %. On the other hands, the same O-PASS-TFC membrane activated with solvent mixture volume ratio of DMF/H2O = 0.5 exhibited enhanced Na2SO4 rejection of 99 %, with greater solution permeance of 3.01 LMH bar−1 (~212 % increase). The correlations between the different activation treatment-membrane structure-separation properties of O-PASS-TFC membranes with different solvent activation degrees were investigated in detail. In this work, the ultrasolvent-resistant property of O-PASS substrate was combined to regulate its TFC membrane structure, and then further to endow the TFC membrane with multiple excellent filtration performance by fully utilizing the solvent activation effect of DMF. Through this strategy, it supplies a facile and promising route for preparation of high efficiency TFC membrane.

Tandem [5,5]-/[3,3]-Rearrangements of Aryl Sulfoxides with Allyl Nitriles

AbstractTandem aromatic rearrangements represent a potent strategy for modulating the regioselectivity of a rearrangement process. In this article, we disclose two novel tandem aromatic rearrangements triggered by sulfonium [5,5]-rearrangement recently developed in our laboratory. Specifically, the [5,5]-rearrangement of aryl sulfoxides with allyl nitriles, followed by [3,3]-Cope rearrangement, forges a seamless tandem [5,5]-/[3,3]-rearrangement cascade, affording ortho-functionalized aryl sulfides. The other tandem process involves [5,5]-rearrangement of aryl sulfoxides with allyl nitriles, followed by nucleophilic addition/DDQ-oxidation-induced [3,3]-Cope rearrangement, eventually yielding meta-functionalized aryl sulfides. Both consecutive rearrangements enrich the repertoire of tandem aromatic rearrangement methodologies.

Potassium tert‐Butoxide‐Promoted Aerobic Dehydrazination of Arylhydrazines: From Arylhydrazines to Substituent Aromatics

AbstractAn efficiently aerobic dehydrazination of arylhydrazines promoted by potassium tert‐butoxide (tBuOK) is detailed in this study. This method smoothly produces aromatics analogues from arylhydrazines using catalytic amount of tBuOK under practical conditions, exhibiting excellent functional group tolerance and a broad substrate scope. The application potential of this approach is further demonstrated through the preparation of deuterated, iodinated and brominated aromatics. Moreover, it shows that this aerobic base‐mediated dehydrazination could be utilized to prepare unsymmetrical aryl sulfides, selenides and tellurides with high efficiency.

Iron-Catalyzed Asymmetric Imidation of Sulfides via Sterically Biased Nitrene Transfer.

Transition-metal-catalyzed enantioselective nitrene transfer to sulfides has emerged as one of the most powerful strategies for rapid construction of enantioenriched sulfimides. However, achieving stereocontrol over highly active earth-abundant transition-metal nitrenoid intermediates remains a formidable challenge compared with precious metals. Herein, we disclose a chiral iron(II)/N,N'-dioxide-catalyzed enantioselective imidation of dialkyl and alkyl aryl sulfides using iminoiodinanes as nitrene precursors. A series of chiral sulfimides were obtained in moderate-to-good yields with high enantioselectivities (56 examples, up to 99% yield, 98:2 e.r.). The utility of this methodology was demonstrated by late-stage modification of complex molecules and synthesis of the chiral insecticide sulfoxaflor and the intermediates of related bioactive compounds. Based on experimental studies and theoretical calculations, a water-bonded high-spin iron nitrenoid species was identified as the key intermediate. The observed stereoselectivity was original from the steric repulsion between the amide unit of the ligand in the chiral cave and the bulky substituent of sulfides. Additionally, dioxazolones proved to be suitable acylnitrene precursors in the presence of an iron(III)/N,N'-dioxide complex, resulting in the formation of enantioselectivity-reversed sulfimides (14 examples, up to 81% yield, 97:3 e.r.).

Generation of benzyne from aryl benziodoxaborole triflate under aqueous conditions and its reactions with alkyl aryl sulfides

Generation of benzyne from aryl benziodoxaborole triflate under aqueous conditions and its reactions with alkyl aryl sulfides

Self-Assembly of a Water-Soluble Pd16 Square Bicupola Architecture and Its Use in Aerobic Oxidation in Aqueous Medium.

Designing supramolecular architectures with uncommon geometries has always been a key goal in the field of metal-ligand coordination-driven self-assembly. It acquires added significance if functional building units are employed in constructing such architectures for fruitful applications. In this report, we address both these aspects by developing a water-soluble Pd16L8 coordination cage 1 with an unusual square orthobicupola geometry, which was used for selective aerobic oxidation of aryl sulfides. Self-assembly of a benzothiadiazole-based tetra-pyridyl donor L with a ditopic cis-[(tmeda)Pd(NO3)2] acceptor [tmeda = N,N,N',N'-tetramethylethane-1,2-diamine] produced 1, and the geometry was determined by single-crystal X-ray diffraction study. Unlike the typically observed tri- or tetrafacial barrel, the present Pd16L8 coordination assembly features a distinctive structural topology and is a unique example of a water-soluble molecular architecture with a square orthobicupola geometry. Efficient and selective aerobic oxidation of sulfides to sulfoxides is an important challenge as conventional oxidation generally leads to the formation of sulfoxide along with toxic sulfone. Cage 1, designed with a ligand containing a benzothiadiazole moiety, demonstrates an ability to photogenerate reactive oxygen species (ROS) in water, thus enabling it to serve as a potential photocatalyst. The cage showed excellent catalytic efficiency for highly selective conversion of alkyl and aryl sulfides to their corresponding sulfoxides, therefore without the formation of toxic sulfones and other byproducts, under visible light in aqueous medium.

Iodophor-Catalyzed Disulfenylation of Amino Naphthalenes with Aryl Sulfonyl Hydrazines.

An iodophor-catalyzed direct disulfenylation of amino naphthalenes with aryl sulfonyl hydrazines in water was developed. A series of aryl sulfides were obtained in moderate to excellent yields. The advantages of this green protocol were the simple reaction conditions (metal-free, water as the solvent, under air), the odorless and easily available sulfur reagent, the broad substrate scope, and gram-scale synthesis. Moreover, the potential application of aryl sulfides was exemplified by further transformations.

Lewis Acid-Catalyzed Formal [4 + 2] Reaction of Alkynyl Sulfides and 2-Pyrones To Access Polysubstituted Aryl Sulfides.

A practical and efficient method to access polysubstituted aryl sulfides has been discovered via a Lewis acid-catalyzed reaction between alkynyl sulfide and 2-pyrone, involving a Diels-Alder/retro-Diels-Alder pathway. Alkynyl sulfide as an electron-rich dienophile and 2-pyrones as electron-poor dienes are conjunctively transformed into a series of polysubstituted aryl sulfides with broad functional group compatibility in good to excellent yields (40 examples, 43-88% yield). The robustness and practicality of the protocol has been demonstrated through gram-scale synthesis and the ease of transformation of the resulting products.

Tetrafluoropyridinyl Thiolate as a Tool for Enabling Photoredox Alkylation of 1,2,4‐Oxadiazoles

AbstractA method for the radical functionalization of 1,2,4‐oxadiazoles using alkyl halides as precursors of radicals is described. The reaction efficiency is determined by potassium tetrafluoropyridinyl thiolate additive, which plays dual role. First, the thiolate converts alkyl halides into more reactive fluorinated aryl sulfides, which undergo photoredox activation of the C−S bond. Second, the thiolate decreases the unproductive loss of alkyl radicals by converting them back to the sulfides.

Antioxidant and antibacterial activities of 5-mercapto(substitutedthio)-4-substituted-1,2,4-triazol based on nalidixic acid: A comprehensive study on its synthesis, characterization, and In silico evaluation

This study introduces a series of novel Alkyl thio-1,2,4-triazole (4a-p) and mercapto-1,2,4-triazole (3a-d) compounds derived from nalidixic acid. The synthesis was streamlined, involving interactions between nalidixic acid hydrazide and various isothiocyanates to yield cyclic and alkyl(aryl) sulfide compounds, characterized using 1H NMR, 13C NMR, IR, and elemental analysis. Antioxidant capabilities were quantified through DPPH and ABTS assays, highlighting significant potential, especially for compound 3d, which demonstrated an ABTS IC50 value of 0.397 μM, on par with ascorbic acid (IC50 = 0.87 μM). Antibacterial efficacy was established through MIC assessments against a broad spectrum of Gram-positive and Gram-negative bacteria, including Candida albicans. Compounds 3b, 4e, 4h, 4j, 4i, 4m, and 4o showed broad-spectrum activity, with 4k and 4m exhibiting pronounced potency against E. coli. Molecular docking studies validated the antibacterial potential, with compounds 4f and 4h showing high binding affinities (docking scores of −9.8 and −9.6 kcal/mol, respectively), indicating robust interactions with the bacterial enzyme targets. These scores underscore the compounds' mechanistic basis for their antibacterial action and support their therapeutic promise. Furthermore, compounds 3b, 4i, and 4m, identified through drug-likeness and toxicity predictions, were highlighted for their favorable profiles, suggesting their suitability for oral antibiotic therapies. This comprehensive study, blending synthetic, in vitro, and in silico approaches, emphasizes the triazole derivatives' potential as future candidates for antibiotic and antioxidant applications, particularly spotlighting compounds 3b, 4i, and 4m due to their promising efficacy and safety profiles.

A micro‐nanohierarchical composite fabric for efficient water transport and outstanding flame retardancy

AbstractTextiles with outstanding moisture transport characteristics and excellent flammability is of vital importance for human beings. In this work, the poly(arylene sulfide sulfone)–polydopamine/polyphenylene sulfide–polydopamine/poly(arylene sulfide sulfone) (PASS‐PDA/PPS‐PDA/PASS) composite fibric with multigradient porous structures from macro to submicron levels prepared via micrometer and nanometer fibers for water transport and evaporation has been fabricated. The introduction of PDA can effectively improve the hydrophilicity of the composite membrane. Meanwhile, superhydrophobic PASS layer with beaded structure was obtained by electrospray as the inner layer. It is found that PASS‐PDA‐72 fabric exhibited outstanding water diffusion property (spreading diameter = 10.47 cm) and ultrafast the water evaporation (0.20 g h−1). Meanwhile, the beaded‐structure PASS fabrics with high hydrophobicity (water contact angle is 130°C) was selected to absorb water from the surface of human skin and transport it to the other side to evaporate quickly, giving the surface of human skin a comfortable and dry environment. What is more, the PASS‐PDA/PPS‐PDA/PASS composite membrane exhibited excellent thermal stability (Tdmax = 544°C) and flame retardancy, which will have potential for the application in the field of fire protection.

Iodine-promoted metal-free synthesis of mono- / di- and tri-substituted aryl sulfides / selenides in aqueous medium

The green and efficient synthesis of mono-, dis- and tri-substituted aryl sulfides and selenides was achieved via I2 mediated reaction of aromatic hydrocarbons with diphenyl disulfide or diselenide. A series of C–S and C–Se coupling products were obtained in good to excellent yield in the presence of 1.0 equiv. I2 using water as solvent at 90 °C. Our study showed that S–S and Se–Se bonds were activated by I2, which acted as a free radical initiator to generate PhS• and PhSe• free radicals, and conversion to C–S–C and C–Se–C bonds through a coupling reaction. The developed method achieves desirable products without using odorous and toxic thiols. This protocol is simple, highly efficiency, and avoids using metal catalyst, and acid and base additives.

Recyclable and Stable Porphyrin-Based Self-Assemblies by Electrostatic Force for Efficient Photocatalytic Organic Transformation.

Development of efficient, stable, and recyclable photocatalysts for organic synthesis is vital for transformation of traditional thermal organic chemistry into green sustainable organic chemistry. In this work, the study reports an electrostatic approach to assemble meso-tetra (4-sulfonate phenyl) porphyrin (TPPS)tetra (4-sulfonate phenyl) porphyrin (TPPS) as a donor and benzyl viologen (BV) as an acceptor into stable and recyclable photocatalyst for an efficient organic transformation reaction - aryl sulfide oxidation. By use of the electrostatic TPPS-BV photocatalysts, 0.1mmol aryl sulfide with electron-donating group can be completely transformed into aryl sulfoxide in 60min without overoxidation into sulfone, rendering near 100% yield and selectivity. The photocatalyst can be recycled up to 95% when 10mg amount is used. Mechanistic study reveals that efficient charge separation between TPPS and BV results in sufficient formation of superoxide which further reacts with the oxidized sulfide by the photocatalyst to produce the sulfoxide. This mechanistic pathway differs significantly from the previously proposed singlet oxygen-dominated process in homogeneous TPPS photocatalysis.

Room temperature synthesis, characterization and enhanced gas transport properties of novel poly(oxindolylidene arylene)s with dibenzothiophene, dibenzothiophene-S-oxide and dibenzothiophene-S,S-dioxide fragments in the main chain

Aromatic sulfur-containing polymers poly(arylene ether sulfone)s and poly(arylene sulfide sulfone)s are widely used in membrane-based gas- and liquid separations and purification technologies. In this work, we report a facile, robust, room temperature synthesis of a series of novel, solution processable aromatic polymers containing dibenzothiophene, dibenzothiophene-S-oxide, and dibenzothiophene-S,S-dioxide fragments in the main chain, alternating with bulky, torsion resistant oxindolylidene groups. The NMR studies of the polymers obtained revealed ladderized, rigid kink-structured backbones. This combination provides membranes with higher permeability and selectivity with gas pairs CO2/CH4, H2/CH4 and H2/N2, close to or even surpassing the 2008 Robeson’s trade-off line, that compare favorably with polysulfones and poly(ether sulfone)s reported in the literature that lie below the 1991 upper bond. Polymer P2-SO2 containing dibenzothiophene-S,S-dioxide fragments showed impressive CO2 and H2 permeabilities (243. 3 and 315.1 Barrer, respectively); on the other hand, P1-SO containing dibenzothiophene-S-oxide exhibited remarkable H2/CH4 and H2/N2 selectivity (127.26 and 99.34, respectively). This work offers a novel and facile route to fabricate various polysulfones and polysulfoxides with reversible-tunable gas separation properties inspired by the concept of rigid kink-structured backbones that shift their gas transport properties towards higher permeability and higher selectivity.