Trimethylsulfonium Research Articles

(Invited) Unveiling the Stability Potential of Organic Sulfonium Cations in Perovskite Solar Cells

Although the power conversion efficiency of perovskite solar cells (PSCs) has skyrocketed, its stability remains a major roadblock to its commercialization. The susceptibility of conventional ammonium-based halide perovskites to ambient environment underscores the necessity of developing alternative aprotic materials. The substitution of protic ammoniums cations with their analogous aprotic sulfonium cations can pave the way for moisture-stable PSCs. Recently, efficiency and stability potential of sulfonium cations in PSCs has been investigated extensively through various engineering approaches. We incorporated trimethylsulfonium iodide and trimethylsulfoxonium iodide as an additive and interfacial modifier to improve the PCE and stability of MAPbI3 and FAPbI3, and FAMACsPbI3-xBrx PSCs. The structural, optoelectronic, and PV properties of sulfur-based cations and their corresponding lower dimensional perovskites are explored. This work further addresses the key challenges and strategies for advancing PSCs by incorporating various derivatives (trimethylsulfonium bromide and 2-carboxyethyl dimethyl sulfonium bromide) of organosulfonium cations.

First clinical evidence that trimethylsulfonium can serve as a biomarker for the production of the signaling molecule hydrogen sulfide

BackgroundHydrogen sulfide (H2S) is established as the third gaseous signaling molecule and is known to be overproduced in down syndrome (DS) due to the extra copy of the CBS gene on chromosome 21, which has been suggested to contribute to the clinical manifestation of this condition. We recently discovered trimethylsulfonium (TMS) in human urine and highlighted its potential as a selective methylation metabolite of endogenously produced H2S, but the clinical utility of this novel metabolite has not been previously investigated. We hypothesize that the elevation of H2S production in DS would be reflected by an elevation in the methylation product TMS. MethodsTo test this hypothesis, a case-control study was performed and the urinary levels of TMS were found to be higher in the DS group (geo. mean 4.5 nM, 95 % CI 2.4–3.9) than in the control (N) group (3.1 nM, 3.5–6.0), p-value 0.01, whereas the commonly used biomarker of hydrogen sulfide, thiosulfate, failed to reflect this alteration in H2S production (15 µM (N) vs. 13 µM (DS), p-value 0.24. ResultsThe observed association is in line with the proposed hypothesis and provides first clinical evidence of the utility of TMS as a novel and more sensitive biomarker for the endogenous production of the third gaseous signaling molecule than the conventionally used biomarker thiosulfate, which is heavily dependent on bacterial hydrogen sulfide production. ConclusionThis work shows that TMS must be explored in clinical conditions where altered metabolism of hydrogen sulfide is implicated.

Surface Reconstruction with Aprotic Trimethylsulfonium Iodide for Efficient and Stable Perovskite Solar Cells.

Organic ammonium salts are widely used for surface passivation to enhance the photovoltaic (PV) performance and stability of perovskite solar cells (PSCs). However, the protic nature of ammonium units results in the quick degradation of perovskites due to the hydrogen bonding interaction with water molecules. Recently, organo-sulfur compounds have attracted growing interest as passivation layers on three-dimensional perovskites due to their moisture-resistive behavior. Herein, trimethylsulfonium iodide (TMSI), an aprotic S-based organic compound, is employed for surface modification of methylammonium lead iodide-based PSCs to impede moisture penetration, improve charge transfer, and passivate surface defects. The TMSI effectively passivates uncoordinated Pb through Pb···S interactions, and the optimized PSC exhibits a power conversion efficiency (PCE) of 21.03% with an open-circuit voltage of ca. 1.13 V under one-sun illumination, while it reached up to 37.58 and 37.69% under low-intensity indoor illuminations, 1000 and 2000 lx with LED 5000 K, respectively. TMSI-treated cells display enhanced device stability by retaining 92.7% of their initial PCE after 50 days of storage in ambient conditions. This study provides a novel and effective surface reconstruction strategy with aprotic materials to improve PV performance and device stability in PSCs.

Effects of ionic liquids as catalysts on liquid crystal aromatic polyester based on thin‐film polymerization technique

AbstractLiquid crystal aromatic polyesters (LCAPs) have been used in wide applications, such as chip packaging and airship skin. The traditional polymerization of LCAP is catalyzed by inorganic salts, for example, sodium acetate. Herein, we reported three kinds of ionic liquids (ILs) as catalysts to promote LCAP polymerization for the first time. The effects of ILs on the polymerization behaviors are investigated by in situ observing the liquid crystal (LC) phase behaviors based on the thin‐film polymerization technique. The evolution of LC phase over time was detailly investigated by analyzing the emergence, fusion, and growth of LC phase. The temperature from 170 to 210°C and the catalyst concentration in range from 0 to 0.5 wt% are compared, showing that temperature at 210°C and catalyst concentration at 0.5 wt% are the best polymerization conditions for all ILs catalysts. In comparison with trimethylsulfonium iodide and piperidine acetate, 1‐ethyl‐3‐methylimidazolium acetate has the best catalytic effect for the polymerization of LCAP in all experimental conditions. The successful polymerization was confirmed by FT‐IR spectra, showing the increased intensity of vibration peak at 1735 cm−1 attributed to the generation of ester groups while the decreased intensities of vibration peaks at 1759 and 1370 cm−1.

Mechanochemically-induced C–S bond transalkylation exchange in the waste nitrile rubber (NBR)/Poly (vinyl chloride) (PVC) insulation materials

Vulcanized acrylonitrile-butadiene rubber (NBR)/poly (vinyl chloride) (PVC) blends are mainly served as insulation rubber-plastic materials. During manufacturing and use, amounts of waste NBR/PVC materials are produced. However, traditional methods of reusing waste are inappropriate. Herein, we innovatively proposed the utilization of mechanochemistry to induce the conversion of irreversible C–S cross-linked bonds in waste NBR/PVC insulation materials into dynamically reversible vitrimer-like network structures. The vitrimer-like structure endowed mobility to the global molecular chains in NBR/PVC materials. And thus, it was essential for the reclaimed products to eliminate the difference between the residual network within waste NBR/PVC materials and the devulcanized phase, improving the mechanical properties. More interestingly, waste NBR/PVC powder dynamically modified by trimethylsulfoniumiodide (TMSI) restored the ability to mix with other materials via thermal processing. The HNBR + CuSO4 compounds were then blended with the modified NBR/PVC powder to prepare mechanically excellent composites with optimum stress of 14.6 MPa and strain of 481.0%. The continuity of the matrix was critical to the mechanical properties of the recycled products, and solid-state shear milling (S3M) played a crucial role in this process, as characterized by various experiments.

Decomposition kinetics and postmortem production of hydrogen sulfide and its metabolites

BackgroundHydrogen sulfide (H2S), an endogenous gas, can also be generated from organics putrefaction. It is difficult for suspected cases of H2S poisoning to determine whether H2S in specimens is ingested by antemortem poisoning or generated from organics putrefaction. The aim of this study was to find the biomarkers of acute H2S poisoning via comparing the concentrations of H2S and its metabolites over time in specimens. MethodsThe H2S-spiked blood and blank blood group were established. The decomposition kinetics and the postmortem production of H2S were studied due to organics putrefaction. The specimens were placed under 4 conditions of 37, 20, 4 and − 20 ℃. The content of H2S in specimens was quantified by gas chromatography-mass spectrometry, and the contents of its metabolites (thiosulfate and trimethylsulfonium) were measured by liquid chromatography-mass spectrometry, and the variation of its concentration was evaluated. ResultsIn H2S-spiked blood, H2S decreased sharply in the initial stage at 37, 20 and 4 °C, and increased first and then decreased later; but it was relatively stable at − 20 °C. In spiked blood, thiosulfate was 9-fold higher than endogenous concentrations, which increased at first and then decreased during storage. Except for thiosulfate at 37 °C, H2S and thiosulfate in blank blood both increased at first and then decreased in storage; but trimethylsulfonium (TMS) gradually decreased over time in both groups. ConclusionsThiosulfate is a reliable biomarker of acute H2S poisoning at − 20℃ within 7 days. But H2S, because of instability and volatility, is not an ideal poisoning marker. TMS is not an appropriate biomarker due to extremely low concentration in blood.

Quantum hybridization negative differential resistance from non-toxic halide perovskite nanowire heterojunctions and its strain control

While low-dimensional organometal halide perovskites are expected to open up new opportunities for a diverse range of device applications, like in their bulk counterparts, the toxicity of Pb-based halide perovskite materials is a significant concern that hinders their practical use. We recently predicted that lead triiodide (PbI3) columns derived from trimethylsulfonium (TMS) lead triiodide (CH3)3SPbI3 (TMSPbI3) by stripping off TMS ligands should be semimetallic, and additionally ultrahigh negative differential resistance (NDR) can arise from the heterojunction composed of a TMSPbI3 channel sandwiched by PbI3 electrodes. Herein, we computationally explore whether similar material and device characteristics can be obtained from other one-dimensional halide perovskites based on non-Pb metal elements, and in doing so deepen the understanding of their mechanistic origins. First, scanning through several candidate metal halide inorganic frameworks as well as their parental form halide perovskites, we find that the germanium triiodide (GeI3) column also assumes a semimetallic character by avoiding the Peierls distortion. Next, adopting the bundled nanowire GeI3-TMSGeI3-GeI3 junction configuration, we obtain a drastically high peak current density and ultrahigh NDR at room temperature. Furthermore, the robustness and controllability of NDR signals from GeI3-TMSGeI3-GeI3 devices under strain are revealed, establishing its potential for flexible electronics applications. It will be emphasized that, despite the performance metrics notably enhanced over those from the TMSPbI3 case, these device characteristics still arise from the identical quantum hybridization NDR mechanism.

Automated Trimethyl Sulfonium Hydroxide Derivatization Method for High-Throughput Fatty Acid Profiling by Gas Chromatography–Mass Spectrometry

Automated Trimethyl Sulfonium Hydroxide Derivatization Method for High-Throughput Fatty Acid Profiling by Gas Chromatography–Mass Spectrometry

Mixed Dimensional Perovskites Heterostructure for Highly Efficient and Stable Perovskite Solar Cells

Heterojunctions constructed upon multidimensional perovskites (1D/3D or 2D/3D) has emerged as an effective approach to improve the photovoltaic performance and stability of perovskite solar cells (PSCs). Herein, 1D trimethyl sulfonium lead triiodide (Me3SPbI3) 1D Me3SPbI3 nanoarrays are successfully synthesized via a two‐step method in aqueous condition, which reflects excellent water resistivity and environmental stability. By incorporating this 1D Me3SPbI3 into lead halide 3D perovskites, heterostructural 1D/3D perovskite photoactive layer with improved morphology, crystallinity, enhanced photoluminescence lifetime, and reduced carrier recombination in comparison to its 3D counterpart is obtained. Moreover, an efficient and stable 1D/3D PSCs with power conversion efficiency (PCE) of 22.06% by using this 1D/3D perovskite are demonstrated. It noticeably maintained 97% of their initial efficiency after 1000 h storage under ambient condition (RH≈50%) without encapsulation. Our study opens up the design protocol for the development of next‐generation highly efficient and stable perovskite solar cells.

Automated Trimethyl Sulfonium Hydroxide Derivatization Method for High-Throughput Fatty Acid Profiling by Gas Chromatography-Mass Spectrometry.

Fatty acid profiling on gas chromatography–mass spectrometry (GC–MS) platforms is typically performed offline by manually derivatizing and analyzing small batches of samples. A GC–MS system with a fully integrated robotic autosampler can significantly improve sample handling, standardize data collection, and reduce the total hands-on time required for sample analysis. In this study, we report an optimized high-throughput GC–MS-based methodology that utilizes trimethyl sulfonium hydroxide (TMSH) as a derivatization reagent to convert fatty acids into fatty acid methyl esters. An automated online derivatization method was developed, in which the robotic autosampler derivatizes each sample individually and injects it into the GC–MS system in a high-throughput manner. This study investigated the robustness of automated TMSH derivatization by comparing fatty acid standards and lipid extracts, derivatized manually in batches and online automatically from four biological matrices. Automated derivatization improved reproducibility in 19 of 33 fatty acid standards, with nearly half of the 33 confirmed fatty acids in biological samples demonstrating improved reproducibility when compared to manually derivatized samples. In summary, we show that the online TMSH-based derivatization methodology is ideal for high-throughput fatty acid analysis, allowing rapid and efficient fatty acid profiling, with reduced sample handling, faster data acquisition, and, ultimately, improved data reproducibility.

Based on transalkylation reaction the rearrangeable conventional sulfur network facile design for vulcanized diolefin elastomers

AbstractAchieving the reversibility of conventional sulfur crosslinking network is beneficial for the sustainability of rubber products. However, sulfur crosslinking network has been considered as an irreversible network. Here, natural rubber (NR) is chosen as an example and trimethylsulfonium iodide (TMSI) can enable the transalkylation reaction between aliphatic sulfonium salts and the alkyl chains of vulcanized NR, which further realizes the rearrangements of sulfur crosslinking network in the elastomers. Such rearrangement reaction enhances the interfacial adhesion and fuse the fractured surface of vulcanized NR. Moreover, the rearrangements of sulfur crosslinking network induced by TMSI conforms to the characteristics of vitrimer network. This work solves the rearrangement problem of conventional sulfur crosslinking network, which is beneficial for the sustainability of rubber products.

Chemical fixation of CO2 with propylene oxide catalyzed by Trimethylsulfonium bromide in the presence of HBr: a computational study

The chemical fixation of CO2 into value-added chemicals has recently received much attention with regard to the utilization of CO2, a gas responsible for global warming. One of the most well-known methods is the fixation of CO2 with epoxides to form cyclic carbonates. In this work, the conversion of CO2 and PO into five-membered cyclic carbonate catalyzed by (CH3)3SBr alone and (CH3)3SBr in the presence of HBr have been studied by using DFT method at B3LYP/6-311 ++ G (d, p)//B3LYP/6-31G (d) level of theory to understand the reaction mechanism and efficiency of the catalyst. Two possible reaction mechanisms (α and β) were considered and it was found that the β pathway is more favorable over α pathway for the catalyzed route in gas phase. The ring-opening step was the rate-determining step that results from the nucleophilic attack of the bromide to the carbon atom of the epoxide. The synergetic effect of HBr is tested as HBD for the (CH3)3SBr/HBr catalyzed reaction and it gave better result and minimized the activation energy for the reaction and the rate-determining step was the ring closure with free energy of activation 5.2 kcal/mol in gas phase.

Methane Generation and Reductive Debromination of Benzylic Position by Reconstituted Myoglobin Containing Nickel Tetradehydrocorrin as a Model of Methyl-coenzyme M Reductase.

Methyl-coenzyme M reductase (MCR), which contains the nickel hydrocorphinoid cofactor F430, is responsible for biological methane generation under anaerobic conditions via a reaction mechanism which has not been completely elucidated. In this work, myoglobin reconstituted with an artificial cofactor, nickel(I) tetradehydrocorrin (NiI(TDHC)), is used as a protein-based functional model for MCR. The reconstituted protein, rMb(NiI(TDHC)), is found to react with methyl donors such as methyl p-toluenesulfonate and trimethylsulfonium iodide with methane evolution observed in aqueous media containing dithionite. Moreover, rMb(NiI(TDHC)) is found to convert benzyl bromide derivatives to reductively debrominated products without homocoupling products. The reactivity increases in the order of primary > secondary > tertiary benzylic carbons, indicating steric effects on the reaction of the nickel center with the benzylic carbon in the initial step. In addition, Hammett plots using a series of para-substituted benzyl bromides exhibit enhancement of the reactivity with introduction of electron-withdrawing substituents, as shown by the positive slope against polar substituent constants. These results suggest a nucleophilic SN2-type reaction of the Ni(I) species with the benzylic carbon to provide an organonickel species as an intermediate. The reaction in D2O buffer at pD 7.0 causes a complete isotope shift of the product by +1 mass unit, supporting our proposal that protonation of the organonickel intermediate occurs during product formation. Although the turnover numbers are limited due to inactivation of the cofactor by side reactions, the present findings will contribute to elucidating the reaction mechanism of MCR-catalyzed methane generation from activated methyl sources and dehalogenation.

Zwanzig Theory Application for Bromide and Iodide Ions in Pure Solvents at 25°C

The Zwanzig theory of dielectric friction has been applied to trimethylsulfonium ion, bromide and iodide ions in different solvents at 25°C. The radius values which obtained from the slope (hydrated radius) and that one which obtained from the intercept (hydrodynamic radius) were calculated and the reason for such difference discussed on the basis of the assumptions of Zwanzig theory.

Zwanzig Theory Application for Bromide and Iodide Ions in Pure Solvents at 25°C

The Zwanzig theory of dielectric friction has been applied to trimethylsulfonium ion, bromide and iodide ions in different solvents at 25°C. The radius values which obtained from the slope (hydrated radius) and that one which obtained from the intercept (hydrodynamic radius) were calculated and the reason for such difference discussed on the basis of the assumptions of Zwanzig theory.

Highly effective carbon-supported gold-ionic liquid catalyst for acetylene hydrochlorination.

The sulfur-containing ionic liquid (IL) trimethylsulfonium iodide (C3H9SI) was used to synthesize an efficient non-mercuric catalyst with HAuCl4·4H2O as a precursor and spherical active carbon (SAC) as a support. Various Au-IL/SAC catalysts were synthesized using the incipient wetness impregnation technique and applied to acetylene hydrochlorination. The 0.3% Au-IL/SAC catalyst showed the best catalytic performance, with an acetylene conversion of 90% at a temperature of 170 °C and gas hourly space velocity (GHSV) of 360 h−1 using water as the solvent. The catalyst also displayed excellent long-term stability: C2H2 conversion was maintained at 97% for up to 200 h (T = 170 °C, GHSV = 90 h−1). Brunauer–Emmett–Teller surface area, thermogravimetric analysis, temperature programmed desorption, X-ray diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy results together showed that the C3H9SI additive significantly improved the dispersion of Au species and inhibited coke deposition on the catalyst surface during the acetylene hydrochlorination reaction. The superior activity and stability of the Au-IL/SAC catalyst make it a green catalyst for the industrial application of acetylene hydrochlorination.

Synthesis, characterization and use of highly stable trimethyl sulfonium tin(IV) halide defect perovskites in dye sensitized solar cells

We report here on the crystal structure and physical properties of ((CH3)3S)2SnX6 (X = Cl, Br, I) compounds as well as the application of ((CH3)3S)2SnI6 in dye-sensitized solar cells. Powder X-ray diffraction and Rietveld analysis show that the materials form a cubic structure with a 0D network of [SnX6] octahedra, which can be considered as a defect variant (AB0.5X3) of the perovskite archetype (ABX3). The electronic band gaps of ((CH3)3S)2SnX6 were determined by UV–Vis reflectance spectroscopy at 4.1, 2.9 and 1.4 eV for X = Cl, Br, and I, respectively. The direct bandgap and its relative decrease in the order of light to heavy halide was independently verified by density-of-states calculations. According to Raman spectroscopy, the lattice vibrations also depend largely on the halogen atom. The air-stable and non-toxic ((CH3)3S)2SnI6 compound was incorporated in electrolyte-free, dye-sensitized solar cells based on the Z907 chromophore chemisorbed onto mesoporous titania electrodes. A power conversion efficiency of 5% is achieved for these photovoltaic devices, confirming efficient charge transport in the bulk ((CH3)3S)2SnI6 and hole extraction at the perovskite-Pt interface.

The Association between the Urinary Excretion of Trimethylselenonium and Trimethylsulfonium in Humans.

Hydrogen sulfide is a signaling molecule that plays important roles in several physiological processes, and its methylation product trimethylsulfonium (TMS) is a natural constituent of human urine that could serve as a biomarker for hydrogen sulfide. In vitro studies showed that the enzyme indole-ethylamine N-methyltransferase (INMT) is responsible for the production of trimethylsulfonium as well as its selenium analogue trimethylselenonium (TMSe). Marked inter-individual variability in TMSe production is associated with genetic polymorphisms in the INMT gene, but it remains unclear whether these polymorphisms affect substrate specificity or general enzymatic activity. Therefore, we explore the association between the TMS and TMSe production phenotypes. Caucasian volunteers were recruited and grouped according to their TMSe status into “TMSe producers” and “TMSe non-producers”, and morning urine samples were collected over 5 consecutive days from each volunteer. A total of 125 urine samples collected from 25 volunteers (13 TMSe producers and 12 TMSe non-producers) were analyzed for total selenium and total sulfur using inductively coupled plasma mass spectrometry (ICPMS), trimethylselenonium using HPLC/ICPMS, and trimethylsulfonium using HPLC/electrospray ionization—triple quadrupole—mass spectrometry (ESI-QQQ-MS). Although there was no correlation between TMS and TMSe urinary levels within the “TMSe producers” group, the “TMSe producers” had urinary levels of TMS 10-fold higher than those of the “TMSe non-producers” (P < 0.001). This result indicates that stratification according to TMSe status or genotype is crucial for the correct interpretation of urinary TMS as a possible biomarker for hydrogen sulfide body pools.

ChemInform Abstract: Nazarov Cyclization of Divinyl and Arylvinyl Epoxides: Application in the Synthesis of Resveratrol‐Based Natural Products.

AbstractA novel variant of the Nazarov cyclization of divinyl epoxides and arylvinyl epoxides, generated in solution from the corresponding ketones and ethyl bromoacetate or trimethylsulfonium iodide is developed.

Solid Phase Micro-extraction (SPME) with In Situ Transesterification: An Easy Method for the Detection of Non-volatile Fatty Acid Derivatives on the Insect Cuticle.

Triacylglycerides (TAGs) and other non-volatile fatty acid derivatives (NFADs) occur in large amounts in the internal tissues of insects, but their presence on the insect cuticle is controversially discussed. Most studies investigating cuticular lipids of insects involve solvent extraction, which implies the risk of extracting lipids from internal tissues. Here, we present a new method that overcomes this problem. The method employs solid phase micro-extraction (SPME) to sample NFADs by rubbing the SPME fiber over the insect cuticle. Subsequently, the sampled NFADs are transesterified in situ with trimethyl sulfonium hydroxide (TMSH) into more volatile fatty acid methyl esters (FAMEs), which can be analyzed by standard GC/MS. We performed two types of control experiments to enable significant conclusions: (1) to rule out contamination of the GC/MS system with NFADs, and (2) to exclude the presence of free fatty acids on the insect cuticle, which would also furnish FAMEs after TMSH treatment, and thus might simulate the presence of NFADs. In combination with these two essential control experiments, the described SPME technique can be used to detect TAGs and/or other NFADs on the insect cuticle. We analyzed six insect species from four insect orders with our method and compared the results with conventional solvent extraction followed by ex situ transesterification. Several fatty acids typically found as constituents of TAGs were detected by the SPME method on the cuticle of all species analyzed. A comparison of the two methods revealed differences in the fatty acid compositions of the samples. Saturated fatty acids showed by trend higher relative abundances when sampled with the SPME method, while several minor FAMEs were detected only in the solvent extracts. Our study suggests that TAGs and maybe other NFADs are far more common on the insect cuticle than usually thought.