Sulfur Chemistry Research Articles

More Than Deoxygenation: Linking Iodate Reduction to Nitrogen, Iron, and Sulfur Chemistry in Reducing Regimes

More Than Deoxygenation: Linking Iodate Reduction to Nitrogen, Iron, and Sulfur Chemistry in Reducing Regimes

Ice origins of OCS and chemistry of CS2-bearing ice mantles

Abstract Understanding the formation of carbonyl sulfide (OCS) in interstellar ices is key to constrain the sulfur chemistry in the interstellar medium (ISM), since it is the only ice S-bearing molecule securely detected thus far. Two general pathways for OCS formation have been proposed: sulfurization of CO (CO+S) and oxidation of CS (CS+O), but their relative contribution in interstellar ices remains unconstrained. We have evaluated the contribution of both pathways to OCS formation upon energetic processing in isotopically-labeled CO2:CS2 and CO:CS2 ice samples at 7−50 K. Our results indicated that formation of OCS through the CS+O pathway was more favorable than through the CO+S pathway, as previously suggested by theoretical calculations. In addition, its relative contribution increased at higher temperatures. Therefore, this pathway could play a role in the ice formation of OCS, especially in warm regions where CO is expected to be preferentially in the gas phase. At the same time, we have explored the chemistry of CS2-bearing, CO2-, CO-, and also H2O-rich ices, that could be relevant to the sulfur interstellar chemistry. We observed formation of a variety of S-bearing products in addition to OCS, including SO2, C3S2, and S2. However, a significant fraction of sulfur was not detected at the end of the experiments, and could be locked in long, undetectable sulfur allotropes, one of the potential carriers of the missing sulfur in the dense ISM.

Dual Sources of S2 Observed in Comet 67P: Insights from Comparing ROSINA Measurements and Laboratory Simulations

Hydrogen sulfide (H2S) is the fifth most abundant molecule observed in the coma of comet 67P/Churyumov–Gerasimenko (67P). Prior to its incorporation into cometary materials, H2S likely underwent ultraviolet (UV) radiation exposure, which is thought to initiate a complex sulfur chemistry. We present an investigation into the UV photochemistry of H2S ices using infrared, Raman, and mass spectrometry techniques. Our study reveals the production of complex sulfur allotropes ranging from S2 to S6, alongside polysulfanes (H2S n , n = 2–3). Temperature-programmed desorption measurements postirradiation of H2S exhibit two peaks for S2 molecules: a broad peak between 80 and 140 K and a distinct peak at ∼245 K. Notably, larger allotropes S3–S5 exclusively display the 245 K peak. Furthermore, ROSINA measurements of the S2/H2S ratio during dust impact events and previously reported S2/H2S ratios in the undisturbed coma are compared to our laboratory-determined S2/H2S values. This analysis identifies two distinct sources of S2: a volatile S2 potentially sublimated directly from the comet’s surface and a secondary source likely resulting from fragmentation of larger sulfur chains during dust impacts. We determined the ratio of produced S2 to the initial H2S for both the volatile component and the refractory component at 245 K with both measurements conducted at an irradiation incident fluence of 2.25 × 1017 photons cm−2. These laboratory-derived S2/H2S ratios exhibit concordance with ROSINA measurements. When extrapolated to incident fluences anticipated in molecular clouds, this photoprocessing mechanism offers a plausible explanation for the measured S2/H2S ratio in comet 67P.

SO2F2 mediated click chemistry enables modular disulfide formation in diverse reaction media

The dynamic disulfide linkage plays a vital role in various biological processes as well as drugs and biomaterials. The conversion of thiols to their corresponding disulfides is a hallmark of sulfur chemistry, but notoriously difficult to control. Achieving optimal reactivity and selectivity continues to pose significant challenges. Here, we describe a click chemistry for disulfide formation from thiols in both batch and flow-mode using SO2F2, which display exceptional selectivity toward disulfide formation through an effective nucleophilic substitution cascade. This reaction’s unique characteristics satisfy the stringent click-criteria with its high thermodynamic driving force, straightforward conditions, wide scope, quantitative yields, exceptional chemoselectivity, and non-chromatographic purification process. The modular synthesis of symmetrical, unsymmetrical, cyclic and polydisulfides is demonstrated, along with the formation of disulfide cross-linked hydrogels.

Generation and Application of Sulfur Ylides in Light‐Mediated Transformations

Sulfur ylides are essential reagents in various organic reactions like epoxidation and cyclopropanation. While traditionally employed in ionic chemistry, recent advancements in visible‐light‐driven photocatalysis reveal their potential as sources of radicals or free carbenes. The photochemical or photocatalytic generation of reactive intermediates using sulfur ylides expands the utility of these reagents in modern organic synthesis, offering sustainable solutions to emerging challenges. Despite early demonstrations in the 1960s, the past years have witnessed a surge in photochemical methods utilizing sulfur ylides as precursors. The use of redox‐active photocatalysts has facilitated numerous radical reactions. This review consolidates key findings in sulfur ylide chemistry, particularly focusing on photo‐mediated reactions, to stimulate further research interest in this dynamic field.

Carbonyl Compounds Regulate Atmospheric Oxidation Capacity and Particulate Sulfur Chemistry in the Coastal Atmosphere.

Carbonyl compounds play a crucial role in the formation of ozone (O3) and secondary aerosols, with recent studies particularly highlighting formaldehyde (HCHO) as a significant contributor to the missing particulate sulfur. However, evaluations based on field observations are limited, especially in clean marine environments. Utilizing observation data from a coastal mountain site in May 2021 in Qingdao, northern China, we reveal the important regulating effect of carbonyls in atmospheric oxidation capacity and particulate sulfur chemistry using detailed chemical box models. Photolysis of gaseous carbonyls accounted for >90% and >60% of the primary sources of HO2 and RO2, respectively, contributing 38% of net O3 production. Notably, HCHO alone constituted 80% of the primary HO2 and 15% of net O3 production. Using a multiphase model with updated HCHO-related chemistry, we determine that HCHO chemistry can account for up to 30% of total particulate sulfur (the sum of hydroxymethanesulfonate and sulfate) and address more than one-third of the simulated sulfate gap. The emission-based multiphase model indicates that the HCHO-related pathway remains significant and can account for 20% of the particulate sulfur under clean marine conditions. These findings underscore the importance of carbonyls, particularly HCHO, in regulating the atmospheric oxidation capacity and particulate sulfur chemistry in the marine atmosphere, urging further laboratory studies on chemical kinetics and field measurements of particle-phase carbonyls.

First Ab Initio Line Lists for Triatomic Sulfur-Containing Molecules: S2O and S3.

We present in this paper the first room temperature rovibrational line lists for the main isotopologues of disulfur monoxide (S2O) and thiozone (S3) variationally computed from newly developed ab initio potential energy and dipole moment surfaces (PESs and DMSs). S2O and S3 are supposed to be potential candidates for astronomical detection, especially in the Venusian atmosphere where sulfur chemistry plays a major role. Contrary to other stable sulfur-containing species like SO2 or H2S, there is much less experimental data for the short-lived reactive S2O and S3 molecules. Indeed, the infrared spectra of S2O and S3 are quite complicated to analyze without consistent theoretical predictions because they contain both high J (∼100) and a lot of hot band transitions, even at T = 296 K. In this work, we have constructed PESs based on the single-reference coupled cluster approach [CCSD(T)] and including corrections due to the scalar relativistic effects, DBOC, and highly excited Slater determinants. The structure of the excited electronic states of S3 was also discussed. The nuclear-motion Eckart-Watson Hamiltonian expressed in terms of normal-mode irreducible tensor operators was used to compute the energy levels. For line intensity calculation, ab initio DMSs were computed at the CCSD(T)/aug-cc-pV5Z level of the theory. Rotation-vibration patterns in the fundamental bands of S2O and S3 have been simulated taking into account the recent Fourier-transform spectra of S2O recorded at the SOLEIL synchrotron. The present work aims at providing line intensities of S2O and S3 that are missing in the literature as well as new spectroscopic support for atmospheric applications.

Thiatruxene-Based Conductive MOF: Harnessing Sulfur Chemistry for Enhanced Proton Transport.

Functionalizing the organic building blocks of electrically conductive MOFs (EC-MOFs) can be a powerful method for adjusting the electronic structure and introducing a specific chemistry. However, designing EC-MOF linkers with reactive functional groups for postsynthetic modification is challenging due to the requirements of d-p conjugation. This work addresses such design limitations by synthesizing an EC-MOF, Cu-thiatruxene (Cu-thiaTRX). This conductive framework incorporated a truxene-based linker with heterocyclic sulfur, allowing for efficient conjugation and an electrical conductivity of 2.2 × 10-2 S cm-1. Harnessing sulfur chemistry in Cu-thiaTRX involves a two-step postsynthetic modification: oxidation and SNAr. The sulfinic groups introduced in the framework enabled tunable proton conductivity, leading to a 200-fold improvement. These results highlight the importance of a rational linker design for functionalization.

Inside Cover Picture

The picture in the background is the old chemistry building of Soochow University, the symbols of S are: 1. for the research field of Prof. Wang Shunyi's group at Soochow University: Organic Sulfur Chemistry; 2. for Soochow University; 3. for Suzhou; 4. for Singapore. We would like to take this opportunity to celebrate the 110th anniversary of the founding of Chemistry and Chemical Engineering in Soochow University, as well as the 30th anniversary of the Suzhou‐Singapore Industrial Park. The cover image portrays the reductive coupling reaction of xanthate esters with sulfur‐containing and selenium‐containing compounds (thio(seleno)sulfonates and disulfides(selenides)) under the nickel‐catalyzed condition. It provides a mild and effective method for the synthesis of unsymmetric sulfides and selenides. More details are discussed in the article by Wang et al. on pages 2453—2458.image

Evidence of both molecular cloud and fluid chemistry in Ryugu regolith.

The sulfur chemistry of (162173) Ryugu particles can be a powerful tracer of molecular cloud chemistry and small body processes, but it has not been well explored. We report identification of organosulfurs and a sulfate grain in two Ryugu particles, A0070 and A0093. The sulfate grain shows oxygen isotope ratios (δ17O = -11.0 ± 4.3 per mil, δ18O = -7.8 ± 2.3 per mil) that are akin to silicates in Ryugu but exhibit mass-independent sulfur isotopic fractionation (Δ33S = +5 ± 2 per mil). A methionine-like coating on the sulfate grain is isotopically anomalous (δ15N = +62 ± 2 per mil). Both the sulfate and organosulfurs can simultaneously form and survive during aqueous alteration within Ryugu's parent body, under reduced conditions, low temperature, and a pH >7 in the presence of N-rich organic molecules. This work extends the heliocentric zone where anomalous sulfur, formed by selective photodissociation of H2S gas in the molecular cloud, is found.

A high‐energy‐density long‐cycle lithium–sulfur battery enabled by 3D graphene architecture

AbstractLithium–sulfur (Li–S) battery is attracting increasing interest for its potential in low‐cost high‐density energy storage. However, it has been a persistent challenge to simultaneously realize high energy density and long cycle life. Herein, we report a synergistic strategy to exploit a unique nitrogen‐doped three‐dimensional graphene aerogel as both the lithium anode host to ensure homogeneous lithium plating/stripping and mitigate lithium dendrite formation and the sulfur cathode host to facilitate efficient sulfur redox chemistry and combat undesirable polysulfide shuttling effect, realizing Li–S battery simultaneously with ultrahigh energy density and long cycle life. The as‐demonstrated polysulfide‐based device delivers a high areal capacity of 7.5 mAh/cm2 (corresponds to 787 Wh/L) and an ultralow capacity fading of 0.025% per cycle over 1000 cycles at a high current density of 8.6 mA/cm2. Our findings suggest a novel strategy to scale up the superior electrochemical property of every microscopic unit to a macroscopic‐level performance that enables simultaneously high areal energy density and long cycling stability that are critical for practical Li–S batteries.

Investigating Sulfur Chemistry in the HD163296 Disk

Sulfur chemistry in the formation process of low-mass stars and planets remains poorly understood. The protoplanetary disks are the birthplace of planets and its distinctive environment provides an intriguing platform for investigating models of sulfur chemistry. We analyzed the Atacama Large Millimeter/submillimeter Array observations of CS 7–6 transitions in the HD 163296 disk and performed astrochemical modeling to explore its sulfur chemistry. We simulated the distribution of sulfur-containing molecules and compared it with observationally deduced fractional column densities. We have found that the simulated column density of CS is consistent with the observationally deduced fractional column densities, while the simulated column density of C2S is lower than the observationally deduced upper limits on column densities. This results indicate that we have a good understanding of the chemical properties of CS and C2S in the disk. We also investigated the influence of the C/O ratio on sulfur-containing molecules and found that the column densities of SO, SO2, and H2S near the central star are dependent on the C/O ratio. Additionally, we found that the N[CS]/N[SO] ratio can serve as a promising indicator of the disk’s C/O ratio in HD 163296. Overall, the disk of HD 163296 provides a favorable environment for the detection of sulfur-containing molecules.

Sulfate Formation Driven by Wintertime Fog Processing and a Hydroxymethanesulfonate Complex With Iron: Observations From Single‐Particle Measurements in Hong Kong

AbstractFog processing has a significant impact on sulfur chemistry in the atmosphere. This study analyzed three winter fog events in Hong Kong using single‐particle aerosol mass spectrometry (SPAMS) and a Monitor for AeRosols and GAses in ambient air (MARGA). Black carbon (BC)‐related carbonaceous particles with substantial sulfate amounts comprised the largest particle number fraction (56.7%). Sulfate mass concentration decreased during fog due to the cloud's effective scavenging, but fog processing notably promoted sulfate formation at the single‐particle level (average peak area increases of 31.2%). Hydroxymethanesulfonate (HMS), an important S(IV) compound and fog tracer, was identified accounting for up to 12% by particle number fraction. Although pH showed a positive correlation (r = 0.53–0.69) with HMS particles in each fog scenario, a negative overall correlation (r = −0.51) was observed. Further analysis revealed that the higher aerosol acidity (pH 0.65–3.11), promoted Fe dissolution, leading to 49% of HMS particles being mixed with Fe, which potentially facilitated sulfate formation via the Fenton reaction. Additionally, around 40% of HMS‐Fe particles are mixed with oxalate, thereby warranting further attention for their potential to cause more intricate sulfur oxidation processes. This study reveals the initial identification of a high mixed‐state of HMS‐Fe, which could potentially serve as a crucial avenue for the formation of sulfate on individual particulate matter. Considering the persistent augmentation of aerosol acidity in the Asian region, this phenomenon necessitates further investigation and attention.

Highly Reversible Positive-Valence Conversion of Sulfur Chemistry for High-Voltage Zinc-Sulfur Batteries.

Sulfur is a promising conversion-type cathode for zinc batteries (ZBs) due to its high discharge capacity and cost-effectiveness. However, the redox conversion of multivalent S in ZBs is still limited, only having achieved S0/S2- redox conversion with low discharge voltage and poor reversibility. This study presents significant progress by demonstrating, for the first time, the reversible S2-/S4+ redox behavior in ZBs with up to six-electron transfer (with an achieved discharge capacity of ≈1284 mAh g-1) using a highly concentrated ClO4 --containing electrolyte. The developed succinonitrile-Zn(ClO4)2 eutectic electrolyte stabilizes the positive-valence S compound and contributes to an ultra-low polarization voltage. Notably, the achieved flat discharge plateaus demonstrate the highest operation voltage (1.54V) achieved to date in Zn‖S batteries. Furthermore, the high-voltage Zn‖S battery exhibits remarkable conversion dynamics, excellent cycling performance (85.7% capacity retention after 500 cycles), high efficiency (98.4%), and energy density (527WhkgS -1). This strategy of positive-valence conversion of sulfur represents a significant advancement in understanding sulfur chemistry in batteries and holds promise for future high-voltage sulfur-based batteries.

1T-rich MoS2 nanosheets anchored on conductive porous carbon as effective polysulfide promoters for lithium–sulfur batteries

The practical applications of lithium-sulfur (Li-S) batteries have severely been hindered by notorious shuttle effect and sluggish redox kinetics of lithium polysulfide intermediates (LiPSs), which bring about rapid capacity degradation, low coulombic efficiency and poor cycling stability. In this work, 1T-rich MoS2 nanosheets are in-situ developed onto the conductive porous carbon matrix (1T-rich MoS2@PC) as efficient polysulfide promotors for high-performance Li-S batteries. The porous carbon skeleton tightly anchors MoS2 nanosheets to prevent their reaggregation and ensures accessible electrical channels, and at the same time provides a favorable confined space that promotes the generation of 1T-rich MoS2 structure. More importantly, the uniformly distributed metallic 1T-rich MoS2 nanosheets not only affords rich sulfphilic sites and high binding energy for immobilizing LiPSs, but also favors rapid electron transfer and LiPSs conversation kinetics, substantially regulating sulfur chemistry in working cells. Consequently, the Li-S cell assembled with 1T-rich MoS2@PC modified separator delivers a remarkable cycling stability with ultralow capacity decay rate of 0.067% over 500 cycles at 1C. Encouragingly, under harsh conditions (high sulfur loading of 4.78 mg cm−2 and low E/S ratio of 8 μL mg−1), a favorable electrochemical performance can still be demonstrated. This study highlights the profitable design of 1T-rich MoS2/carbon based electrocatalyst for suppressing shuttle effect and promoting catalytic conversation of LiPSs, and has the potential to be applied to in other energy storage systems.

One-step growth of ultrathin CoSe2 nanobelts on N-doped MXene nanosheets for dendrite-inhibited and kinetic-accelerated lithium–sulfur chemistry

The practical application of lithium–sulfur (Li–S) batteries is inhibited by the shuttle effect of lithium polysulfides (LiPSs) and slow polysulfide redox kinetics on the S cathode as well as the uncontrollable growth of dendrites on the Li metal anode. Therefore, both cathode and anode sides must be considered when modifying Li−S batteries. Herein, two-dimensional (2D) ultrathin CoSe2 nanobelts are in situ grown on 2D N-doped MXene nanosheets (CoSe2@N-MXene) via one-step solvothermal process for the first time. Owing to its unique 2D/2D structure, CoSe2@N-MXene can be processed to crumpled nanosheets by freeze-drying and flexible and freestanding films by vacuum filtration. These crumpled CoSe2@N-MXene nanosheets with abundant active sites and inner spaces can act as S hosts to accelerate polysulfide redox kinetics and suppress the shuttle effect of LiPSs owing to their strong adsorption ability and catalytic conversion effect with LiPSs. Meanwhile, the CoSe2@N-MXene film (CoSe2@NMF) can act as a current collector to promote uniform Li deposition because it contains lithiophilic CoSe2 and N sites. Under the systematic effect of CoSe2@N-MXene on S cathode and Li metal anode, the electrochemical and safety performance of Li–S batteries are improved. CoSe2@NMF also shows excellent storage performances in flexible energy storage devices.

Contribution of expanded marine sulfur chemistry to the seasonal variability of dimethyl sulfide oxidation products and size-resolved sulfate aerosol

Abstract. Marine emissions of dimethyl sulfide (DMS) and the subsequent formation of its oxidation products methanesulfonic acid (MSA) and sulfuric acid (H2SO4) are well-known natural precursors of atmospheric aerosols, contributing to particle mass and cloud formation over ocean and coastal regions. Despite a long-recognized and well-studied role in the marine troposphere, DMS oxidation chemistry remains a work in progress within many current air quality and climate models, with recent advances exploring heterogeneous chemistry and uncovering previously unknown intermediate species. With the identification of additional DMS oxidation pathways and intermediate species that influence the eventual fate of DMS, it is important to understand the impact of these pathways on the overall sulfate aerosol budget and aerosol size distribution. In this work, we update and evaluate the DMS oxidation mechanism of the chemical transport model GEOS-Chem by implementing expanded DMS oxidation pathways in the model. These updates include gas- and aqueous-phase reactions, the formation of the intermediates dimethyl sulfoxide (DMSO) and methanesulfinic acid (MSIA), and cloud loss and aerosol uptake of the recently quantified intermediate hydroperoxymethyl thioformate (HPMTF). We find that this updated mechanism collectively decreases the global mean surface-layer gas-phase sulfur dioxide (SO2) mixing ratio by 40 % and enhances the sulfate aerosol (SO42-) mixing ratio by 17 %. We further perform sensitivity analyses exploring the contribution of cloud loss and aerosol uptake of HPMTF to the overall sulfur budget. Comparing modeled concentrations to available observations, we find improved biases relative to previous studies. To quantify the impacts of these chemistry updates on global particle size distributions and the mass concentration, we use the TwO-Moment Aerosol Sectional (TOMAS) aerosol microphysics module coupled to GEOS-Chem and find that changes in particle formation and growth affect the size distribution of aerosol. With this new DMS-oxidation scheme, the global annual mean surface-layer number concentration of particles with diameters smaller than 80 nm decreases by 16.8 %, with cloud loss processes related to HPMTF being mostly responsible for this reduction. However, the global annual mean number of particles larger than 80 nm (corresponding to particles capable of acting as cloud condensation nuclei, CCN) increases by 3.8 %, suggesting that the new scheme promotes seasonal particle growth to these sizes.

Simulating the Volcanic Sulfate Aerosols From the 1991 Eruption of Cerro Hudson and Their Impact on the 1991 Ozone Hole

AbstractThe Chilean volcano Cerro Hudson erupted between August 8th and 15th, 1991, injecting between 1.7 and 2.9 Tg of SO2 into the upper troposphere and lower stratosphere. We simulate this injection using the Goddard Earth Observing System Earth system model with detailed sulfur chemistry and sectional aerosol microphysics, focusing on the resulting aerosols and their contribution to the 1991 Antarctic Austral Springtime ozone hole. The simulations show a column ozone deficit (12 DU) in the Southern Hemisphere vortex collar region. The majority of this effect is between 10 and 20 km and due to heterogeneous chemistry. The model shows a 26% decrease in ozone from background levels at these altitudes, compared with in‐situ observations of a 50% decrease. Above 20 km, the dynamical response to the eruption also causes lower ozone values, a novel modeling result. This experiment highlights potential interactions between proposed solar radiation management geoengineering aerosols and volcanic eruptions.

Modelling of sulfur chemistry in a fog episode in northern China and implication for the efficacy of SO2 emission control

Fog water phase is an effective media for aqueous sulfate formation, especially in polluted urban areas. Fog events frequently occur in northern China during wintertime, which are characterized by increased aerosol loadings with sulfate concentrations reaching about 200 micrograms per cubic meters in 2010s. Studies on sulfur chemistry in fog events specifically for this region are inadequate. In this study, we combine the in-situ measurements in a fog episode in winter, 2015 with a multiphase chemical box model to interpret the sulfur species transformation and their key drivers in fog aqueous phase. Our model results demonstrate that the oxidation by NO2 in fog water serves as the most important pathway, explaining 97% of the sulfate production. High liquid water content in fog and elevated precursors concentrations are the major drivers of rapid sulfate formation. In line with observational studies, the reaction of dissolved SO2 and HCHO yields the production of hydroxymethanesulfonate (HMS) equivalent to 11% of the sulfate mass. Given the high dependence of sulfate and HMS production rates to liquid phase acidity, the nonlinear response of their mass concentrations to the air pollution policies should be further examined.

Cross Dehydrogenative Coupling of SF4-Alkyne with Tetrahydroisoquinolines.

This study introduces a dual-catalytic method for cross-dehydrogenative coupling (CDC) between tetrahydroisoquinolines and Py-SF4-alkyne using visible-light photoredox catalysis. This protocol enables selective C(sp3)-H alkynylation, expanding the synthetic toolkit for SF4-based molecules. Demonstrating efficiency and substrate versatility, this approach opens new avenues in hexacoordinated tetrafluorinated sulfur chemistry and CDC strategies and holds significant promise for drug discovery and materials science.