Alkyl Sulfides Research Articles

Silica-coated nanomagnetite-supported oxovanadium(V) Schiff base complex: Preparation, characterization, and catalytic application for the oxidation of sulfides

In this paper, an oxovanadium(V) complex, prepared with a tridentate ONO Schiff base by reacting nicotinic hydrazide with 3-methoxysalicylaldehyde, was immobilized on the surface of the silica-coated magnetite nanoparticles. After successful preparation and complete characterization (FT–IR, SEM, XRD, TEM, VSM, EDX, and ICP), the catalytic activity of the magnetic organic–inorganic nanocomposite was explored for the green oxidation reaction of different kinds of aryl and alkyl sulfides employing hydrogen peroxide and methanol under reflux conditions. Significant features such as simple work-up, fast reaction, higher product yield, and reusability of the catalyst enhance the efficiency of this catalytic procedure economically and environmentally.

Assessment of the Authenticity of Whisky Samples Based on the Multi-Elemental and Multivariate Analysis.

Two hundred and five samples of whisky, including 170 authentic and 35 fake products, were analyzed in terms of their elemental profiles in order to distinguish them according to the parameter of their authenticity. The study of 31 elements (Ag, Al, B, Ba, Be, Bi, Cd, Co, Cr, Cu, Li, Mn, Mo, Ni, Pb, Sb, Sn, Sr, Te, Tl, U, V, Ca, Fe, K, Mg, P, S, Ti and Zn) was performed using the Inductively Coupled Plasma Mass Spectrometry (ICP-MS), Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) and Cold Vapor-Atomic Absorption (CVAAS) techniques. Additionally, the pH values of all samples were determined by pH-meter, and their isotopic ratios of 88Sr/86Sr, 84Sr/86Sr, 87Sr/86Sr and 63Cu/65Cu were assessed, based on the number of counts by ICP-MS. As a result of conducted research, elements, such as Mn, K, P and S, were identified as markers of whisky adulteration related to the age of alcohol. The concentrations of manganese, potassium and phosphorus were significantly lower in the fake samples (which were not aged, or the aging period was much shorter than legally required), compared to the original samples (in all cases subjected to the aging process). The observed differences were related to the migration of these elements from wooden barrels to the alcohol contained in them. On the other hand, the sulfur concentration in the processed samples was much higher in the counterfeit samples than in the authentic ones. The total sulfur content, such as that of alkyl sulfides, decreases in alcohol with aging in the barrels. Furthermore, counterfeit samples can be of variable origin and composition, so they cannot be characterized as one group with identical or comparable features. Repeatedly, the element of randomness dominates in the production of these kinds of alcohols. However, as indicated in this work, the extensive elemental analysis supported by statistical tools can be helpful, especially in the context of detecting age-related adulteration of whisky. The results presented in this paper are the final part of a comprehensive study on the influence of selected factors on the elemental composition of whisky.

Antisolvent Treatment on Wet Solution‐Processed CuSCN Hole Transport Layer Enables Efficient and Stable Perovskite Solar Cells

AbstractAmong the various inorganic hole‐transporting materials for perovskite solar cells (PSCs), CuSCN is identified as a promising candidate for commercialization applications owing to its abundance and solution processability with alkyl sulfides. Although CuSCN possesses high intrinsic thermal stability, the existence of diethyl sulfide (DES) residue during the wet processing of CuSCN films accelerates perovskite degradation, impeding the practical application of CuSCN in PSC applications. This study demonstrates a new antisolvent‐treatment strategy to extract DES residue from CuSCN. The antisolvent treatment with the aid of diethyl ether (DEE) successfully results in a dense and high‐quality CuSCN film with improved surface morphology, trap density, and hole extraction ability. Consequently, the power conversion efficiency of DEE‐treated CuSCN‐based PSCs improves from 16.84% to 18.34% with superior long‐term stability. This study provides a simple method for the preparation of high‐quality CuSCN films that can effectively be applied to the large‐area fabrication of CuSCN‐based PSCs.

Three-Component Friedel-Crafts Transformations: Synthesis of Alkyl and Alkenyl Trifluoromethyl Sulfides and Alkenyl Iodides.

Straightforward and mild hexafluoroisopropanol (HFIP)-mediated, metal-free, three-component Friedel-Crafts approaches are reported for the synthesis of alkenyl and alkyl trifluoromethyl sulfides from arenes, (PhSO2)2NSCF3, and alkynes or alkenes, respectively. The transformations proceed with high regio- and stereochemical control via the initial formation of cationic thiirenium and thiiranium intermediates, respectively, followed by Friedel-Crafts reactions with the arene. A mechanistically related three-component synthesis of alkenyl iodides from arenes, alkenes, and N-iodosuccinimide is also reported.

Iodine-promoted C-H sulfidation of electron-deficient fluorine-containing arenes with thiols or diselenides leading to unsymmetrical introduction of sulfide or selenide moieties onto tetrafluorobenzene

Described herein is a process that accomplishes the iodine-promoted C-H sulfidation of electron-deficient fluorine-containing aromatic compounds with benzenethiols. This method effectively enables the unsymmetrical bis-sulfidation of pentafluorobenzene. Also, this oxidizing system could be applied to the C-H selenation of fluorine-containing aromatic compounds bearing either alkyl or aryl sulfide moieties, which could plausibly lead to the introduction of two different chalcogen atoms on tetrafluorobenzene derivatives.

Thiacalixarenes with Sulfur Functionalities at Lower Rim: Heavy Metal Ion Binding in Solution and 2D-Confined Space.

Sulfur-containing groups preorganized on macrocyclic scaffolds are well suited for liquid-phase complexation of soft metal ions; however, their binding potential was not extensively studied at the air–water interface, and the effect of thioether topology on metal ion binding mechanisms under various conditions was not considered. Herein, we report the interface receptor characteristics of topologically varied thiacalixarene thioethers (linear bis-(methylthio)ethoxy derivative L2, O2S2-thiacrown-ether L3, and O2S2-bridged thiacalixtube L4). The study was conducted in bulk liquid phase and Langmuir monolayers. For all compounds, the highest liquid-phase extraction selectivity was revealed for Ag+ and Hg2+ ions vs. other soft metal ions. In thioether L2 and thiacalixtube L4, metal ion binding was evidenced by a blue shift of the band at 303 nm (for Ag+ species) and the appearance of ligand-to-metal charge transfer bands at 330–340 nm (for Hg2+ species). Theoretical calculations for thioether L2 and its Ag and Hg complexes are consistent with experimental data of UV/Vis, nuclear magnetic resonance (NMR) spectroscopy, and single-crystal X-ray diffractometry of Ag–thioether L2 complexes and Hg–thiacalixtube L4 complex for the case of coordination around the metal center involving two alkyl sulfide groups (Hg2+) or sulfur atoms on the lower rim and bridging unit (Ag+). In thiacrown L3, Ag and Hg binding by alkyl sulfide groups was suggested from changes in NMR spectra upon the addition of corresponding salts. In spite of the low ability of the thioethers to form stable Langmuir monolayers on deionized water, one might argue that the monolayers significantly expand in the presence of Hg salts in the water subphase. Hg2+ ion uptake by the Langmuir–Blodgett (LB) films of ligand L3 was proved by X-ray photoelectron spectroscopy (XPS). Together, these results demonstrate the potential of sulfide groups on the calixarene platform as receptor unit towards Hg2+ ions, which could be useful in the development of Hg2+-selective water purification systems or thin-film sensor devices.

Synthesis, crystal structure, spectral characterization, theoretical studies, and investigation of catalytic activity in selective oxidation of sulfides by oxo-peroxo tungsten(VI) Schiff base complex

A novel oxo–peroxo tungsten(VI) Schiff base complex, [WO(O2)L(CH3OH)], a homogeneous catalyst for sulfoxidation was synthesized by treating WO3 in the presence of H2O2 with a dibasic tridentate (ONO) Schiff base ligand. The complex was characterized by FT–IR, 1H NMR, and 13C NMR spectroscopy. Moreover, the structure of the crystalline tungsten(VI) complex was further investigated by single crystal X-ray diffraction analysis (SC-XRD). The crystal structure analysis revealed that the complex is hepta-coordinated, and metal ion is surrounded by ONO set of the coordinated doubly deprotonated ligand to adopt a distorted pentagonal–bipyramidal geometry. The theoratical calculations of the geometrical parameters, frontier molecular orbitals (FMOs), molecular electrostatic potential (MEP), and natural bond orbital (NBO) analysis of the synthesized compounds utilizing DFT at the B3LYP level of theory at the Def2-TZVP basis set revealed that the predicted data match the experimental results. The main purpose of the current study is to employ the synthesized W complex for its homogeneous catalytic effectiveness for the oxidation of aryl and alkyl sulfides in ethanol by using 30% aqueous H2O2.

Proton exchange membranes containing densely alkyl sulfide sulfonated side chains for vanadium redox flow battery

Due to further increase the performance of aromatic sulfonated proton exchange membrane (PEM) and make it play a better role in vanadium redox flow battery (VRFB), a series of poly(aryl ether sulfone)s containing eight alkyl sulfide sulfonated side chains (8SPAES-xx) are designed and synthesized. Their molecular structure, phase morphology and some selective properties were investigated in detail, respectively. It is confirmed that 8SPAES-xx membranes have clear hydrophilic/hydrophobic phase separation morphology. These membranes with the ion exchange capacity values of 1.08–1.61 mmol/g exhibit excellent ionic conductivity as well as moderate water uptake and good dimensional stability, and their values are in the range of 25–96 mS/cm, 8–28% and 5–17% at 30 °C, respectively. Among them, the proton conductivity of 8SPAES-12 membrane is 82 mS/cm at 30 °C, which exceeds the ionic conductivity of Nafion 117 (79 mS/cm). The membrane also shows high ion selectivity and excellent battery performance. At current density of 60 mA/cm 2 , the highest energy efficiency of VRFB with 8SPAES-12 membrane is 87.3%, which is higher than that of Nafion 117 (83.8%). Furthermore, the efficiency of VRFB with 8SPAES-12 membrane remains good cycle stability. • PEMs containing eight alkyl sulfide sulfonated side chains are prepared for VRFB. • 8SPAES-xx shows clear hydrophilic/hydrophobic phase separation morphology. • 8SPAES-12 has excellent ionic conductivity and high ion selectivity. • 8SPAES-12 membrane exhibits high cell efficiency as well as good stability.

Modification of magnetic nanoparticles surface by oxovanadium(V) complex as a highly efficient heterogeneous nanocatalyst for the green sulfoxidation of sulfides

The present study describes the synthesis of a new nanomagnetic-supported oxovanadium(V) complex with the tridentate Schiff base ligand derived from the condensation reaction between 5-bromosalicylaldehyde and nicotinic acid hydrazide. The supported complex was fully characterized using various physicochemical techniques such as FT-IR, SEM, EDS, TEM, XRD and VSM. Moreover, the obtained heterogeneous nanocatalyst was utilized in the sulfoxidation of the different alkyl and aryl sulfides by using H2O2 in ethanol under reflux conditions. The magnetic nanocatalyst can be recycled magnetically and can be reused several times without a considerable loss of activity.

Synthesis, spectral characterization, crystal structure and catalytic activity of a novel dioxomolybdenum Schiff base complex containing 4-aminobenzhydrazone ligand: A combined experimental and theoretical study

A novel dioxomolybdenum Schiff base complex, [MoO2(L)(H2O)], was synthesized by the reaction of MoO2(acac)2 and an ONO donor Schiff base ligand (H2L:(E)-4-amino-N'-(3-ethoxy-2-hydroxybenzylidene)benzohydrazide) derived by the condensation of 4-aminobenzohydrazide and 3-ethoxysalicylaldehyde. The synthesized ligand and complex were characterized by various spectroscopic techniques like FT-IR, 1H NMR, 13C NMR, and elemental analysis (CHN). The structure of the complex was confirmed by single crystal X-ray diffraction analysis (SC-XRD). The geometry around the central metal ion in the complex was distorted octahedral as revealed by the data collected from diffraction studies. Theoretical calculations of the synthesized compounds, carried out by DFT using B3LYP and PBE0 levels of theory at the Def2-TZVP basis set, indicated that the calculated results are in agreement with the experimental findings. Moreover, the catalytic efficiency of the complex was investigated by oxidizing the aryl and alkyl sulfides in the presence of 30 % aqueous H2O2 in ethanol.

Sulfoxide and Sulfone Synthesis via Electrochemical Oxidation of Sulfides.

The oxidation of diaryl sulfides and aryl alkyl sulfides to the corresponding sulfoxides and sulfones under electrochemical conditions is reported. Sulfoxides are selectively obtained in good yield under a constant current of 5 mA for 10 h in DMF, while sulfones are formed as the major product under a constant current of 10 or 20 mA for 10 h in MeOH. The oxygen of both the sulfoxide and sulfone function is derived from water.

Synthesis, spectra (FT-IR, NMR) investigations, DFT, FMO, MEP, NBO analysis and catalytic activity of MoO2(VI) complex with ONO tridentate hydrazone Schiff base ligand

A new dioxomolybdenum(VI) complex has been successfully prepared by the reaction of an ONO donor Schiff base, derived by condensing 4-amino-2-hydroxybenzohydrazide and 3-ethoxysalicylaldehyde, with MoO2(acac)2. The structures of synthesized products were explored spectroscopically through FT-IR, 1H & 13C NMR and by elemental composition (CHN) through combustion analysis. The tridentate Schiff base ligand is bonded to the central metal through its deprotonated enolic and phenolic oxygen atoms and by the nitrogen of the azomethine group. The interpretation of the data obtained through diffraction analysis validates the distorted octahedral geometry for the prepared metal complex. Furthermore, the catalytic potential of the molybdenum complex was explored for the selective oxidation of the aryl and alkyl sulfides to the corresponding sulfones in the presence of 30% aqueous H2O2 in ethanol. The main edge of the present catalytic work is the accomplishment of reaction in a short period of time, high percentage yield and easy work-up procedure.

Synthesis, spectral characterization, SC-XRD, HSA, DFT and catalytic activity of novel dioxovanadium(V) complex with aminobenzohydrazone Schiff base ligand: An experimental and theoretical approach

A new dioxovanadium(V) complex was prepared by the reaction of VO(acac)2 with a tridentate ONO donor Schiff base, derived by condensing 3-ethoxysalicylaldehyde and 4-aminobenzohydrazide. The structures of synthesized products were characterized spectroscopically through FT-IR, 1H &13C NMR and by elemental composition through combustion analysis. The structure of the complex was determined with the help of single crystal X-ray crystallography. It was inferred from the diffraction data that the geometry around the central metal ion in the complex is distorted square pyramidal. The tridentate Schiff base ligand is bonded to the central metal through the oxygen of the carbonyl group, the deprotonated phenolic oxygen atom and the azomethine nitrogen. The pyramid base is completed by other oxo ligands that are in cis positions. The theoretical calculations, performed by DFT using B3LYP/Def2-TZVP level of theory, determined that the intended outcomes are in compliance with the actual consequences. Furthermore, the catalytic potential of the vanadium complex was explored for the selective oxidation of the aryl and alkyl sulfides to the corresponding sulfones in the presence of 30% aqueous H2O2 in ethanol. In this work, rPBE and B3LYP methods are used to locate transition structures and to compare free energies of reactants, transition structures and the products involved in the reaction. Analyzing nudge elastic band data shows that the barrier free energy for the oxidation of sulfide to sulfoxide and sulfone are 13 and 83 kcal.mol−1, respectively. The main advantages of the present catalytic study are high yields of the products, less time required for the completion of the reaction and simple work-out procedure.

Cationic living polymerization of cyclic dithiocarbonates involving sulfide-migration

Ring-opening polymerization of cyclic dithiocarbonates was attempted by varying reaction conditions (temperature, concentration, and solvents) to achieve a high polymer conversion. The participation of neighboring sulfide groups in the ring opening was demonstrated by selective sulfide migration and evaluated by composition analysis of the resulting copolymer. The migration was accelerated by electron-enriching substituents on the aryl sulfide and led to the formation of homopolymers with alkyl sulfides. The isomerization of the monomer encountered in the polymerization reduced with sulfide migration and exclusively occurred as substituted by a trityl sulfide. Three catalytic isomerization pathways were proposed for the polymerization mechanism, wherein the electronic and steric contributions of a substituted sulfide group were considered to rationalize the competitive formation of polymers and isomers. The polymerization of a monomer carrying two neighboring groups of butyl sulfide and benzoate proceeded to homopolymerization involving the migration of a sulfide group. The preferential migration was confirmed by the isolation of a six-membered cyclic carbonate as the main fragment product of depolymerization that occurred in the presence of potassium tert-butoxide. A reactive chain end in living polymerization was modified by an in situ reaction with sodium dithiocarbamate. A linear correlation between experimental and theoretical number average molecular weights of the prepared polymers was investigated with polymer conversion variance. The neutralized chain-end improved the chemical stability of the prepared poly(dithiocarbonate)s, and a stable polydispersity was obtained. The thermal decomposition temperature, Td (10% loss), of a polydithiocabonate was measured at 189 °C and the corresponding value after end-capping of the polymer was 285 °C.

Oxovanadium and dioxomolybdenum complexes: synthesis, crystal structure, spectroscopic characterization and applications as homogeneous catalysts in sulfoxidation

New oxovanadium and dioxomolybdenum Schiff base complexes, [VO(L)(OCH3)] n and [MoO2(L)(CH3OH)], were synthesized by treating an ONO donor Schiff base (H2L) derived by condensation of 3-ethoxysalicylaldehyde and nicotinic hydrazide with oxo and dioxo acetylacetonate salts of vanadium and molybdenum (VO(acac)2 and MoO2(acac)2), respectively. The synthesized ligand and complexes were characterized by FTIR, multinuclear (1H, 13C) NMR, elemental and single crystal X-ray diffraction analysis. In both complexes, the geometry around the central metal ions was distorted octahedral as revealed by diffraction studies. Theoretical calculations of the synthesized compounds were carried out by DFT at B3LYP/Def2-TZVP level of theory, which showed good correlation with the experimental results. Moreover, the catalytic efficiency of both complexes was investigated by oxidizing aryl and alkyl sulfides in the presence of 30% H2O2 in ethanol.

Development and optimization of analytical methods for the detection of 18 taste and odor compounds in drinking water utilities

Taste and odor (T&O) issues have been a major concern among drinking water utilities as source waters are becoming increasingly vulnerable to compounds released during algal blooms as well as non-algal compounds. While most of the literature focuses on the two most common T&O compounds – 2-MIB and geosmin, there are other compounds that have the potential to cause T&O events. The aim of this study was to develop an advanced analytical method using solid phase microextraction (SPME) and gas chromatography-tandem mass spectrometry (GC-MS/MS) to identify 18 T&O compounds belonging to various odor classes. The developed method was optimized for the 18 analytes and implemented to determine the holding time of the compounds in raw and treated (distribution system point-of-entry or PoE) drinking water matrices. Compounds belonging to certain classes such as pyrazines and anisoles were found to be “stable” (< 30% loss) in all tested waters for up to two weeks, while aldehydes, ketones, esters and alkyl sulfides showed > 30% loss within 96 h in raw water. Preservation of samples at low pH (< 2) using hydrochloric acid increased the holding times and reduced losses within 96 h for aldehydes, ketones and esters. The paper also discusses the occurrence of these compounds with water utilities from the Midwest and Eastern US during the summer months. The study detected eight T&O compounds - 2-MIB, geosmin, β-cyclocitral, β-ionone, hexanal, indole, dimethyl disulfide and dimethyl trisulfide. While five compounds were detected above their threshold concentrations in the raw water, two of them (2-MIB and geosmin) were detected above threshold in the PoE samples.

Visible‐Light‐Promoted Reversible Sulfide/Iodide Exchange in Fluoroalkyl Sulfides Enabled by Electron Donor‐Acceptor Complex Formation

AbstractCatalyst‐free visible‐light‐mediated exchange of two photoredox active groups, a 4‐perfluoropyridinylthio group and an iodide group, attached to a fluorinated alkyl fragment is described. The reaction can be preparatively performed in both directions by appropriate choice of wavelength, solvent, and counterion. In the forward reaction, alkyl sulfide interacts with an iodide anion to give alkyl iodide and a thiolate anion, with the driving force provided by blue light (455 nm). In the backward process, fluorinated alkyl iodide interacts with the thiolate under violet light (400 nm). The reactions proceed through the formation of electron donor‐acceptor (EDA) complexes, which were observed by UV/Vis absorption or NMR spectroscopies. Evidence of the sulfur–iodide interaction was supported by X‐ray analysis.

Selective oxidative intermolecular carbosulphenylation of aryl alkenes with thiols and nucleophiles via a 1,2-dithioethane intermediate

A periodate lithium-oxidized difunctionalisation of aryl alkenes with thiols and electron-rich aromatics was achieved, selectively affording more than thirty carbosulphenylated products. Both experiments and quantum chemical calculations demonstrated the radical-polar nature of the processes, and that 1,2-dithioethane and thiiranium ions might play the role of intermediates.

Row orientation effects on chemical composition and aromatic profile of Syrah winter wines

Abstract Sunlight and heating influence leaf and grape metabolism and therefore wine quality. As a recent management tool, no information exists on the effects of grapevine row orientation on the wine composition of Syrah vines within the context of double pruning management, a technique used to transfer the grape harvest from the wet summer to the dry winter season. This is a first attempt to investigate the wine composition from north-south- (NS) and east-west- (EW) oriented Syrah winter vines. EW wine samples had higher total acidity, residual sugars, alcohol and color hue, whereas NS wines exhibited higher content of color intensity, anthocyanins, total phenolics, total phenolic index, ashes and pH. The identification of volatile compounds was tentatively performed and demonstrated the presence of alkanes, volatile phenols and alkyl sulfide in NS wines, while butyrolactone and beta-damascenone were found mainly in EW wines. Row orientation contributed to wine composition and could be used as a management tool for obtaining individual wine styles.

Transition-metal-free decarboxylative thiolation of stable aliphatic carboxylates.

A transition-metal-free decarboxylative thiolation protocol is reported in which primary, secondary, tertiary (hetero)aryl acetates and α-CN substituted acetates undergo the decarboxylative thiolation smoothly, to deliver a variety of functionalized aryl alkyl sulfides in moderate to excellent yields. Aryl diselenides are also amenable substrates for construction of C–Se bonds under the simple and mild reaction conditions. Moreover, the protocol is successfully applied to the late-stage modification of pharmaceutical carboxylates with satisfactory chemoselectivity and functional-group compatibility.