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1. Chemical dynamics study on the gas-phase reaction of the D1-silylidyne radical (SiD; X ² Π) with deuterium sulfide (D ₂ S) and hydrogen sulfide (H ₂ S)

   https://doi.org/10.1039/d1cp01629f  

   Goettl, Shane J.; Doddipatla, Srinivas; Yang, Zhenghai; He, Chao; Kaiser, Ralf I.; Silva, Mateus X.; Galvão, Breno R.; Millar, Tom J. (June 2021, Physical Chemistry Chemical Physics)

   The reactions of the D1-silylidyne radical (SiD; X 2 Π) with deuterium sulfide (D 2 S; X 1 A 1 ) and hydrogen sulfide (H 2 S; X 1 A 1 ) were conducted utilizing a crossed molecular beams machine under single collision conditions. The experimental work was carried out in conjunction with electronic structure calculations. The elementary reaction commences with a barrierless addition of the D1-silylidyne radical to one of the non-bonding electron pairs of the sulfur atom of hydrogen (deuterium) sulfide followed by possible bond rotation isomerization and multiple atomic hydrogen (deuterium) migrations. Unimolecular decomposition of the reaction intermediates lead eventually to the D1-thiosilaformyl radical (DSiS) (p1) and D2-silanethione (D 2 SiS) (p3) via molecular and atomic deuterium loss channels (SiD–D 2 S system) along with the D1-thiosilaformyl radical (DSiS) (p1) and D1-silanethione (HDSiS) (p3) through molecular and atomic hydrogen ejection (SiD–H 2 S system) via indirect scattering dynamics in barrierless and overall exoergic reactions. Our study provides a look into the complex dynamics of the silicon and sulfur chemistries involving multiple deuterium/hydrogen shifts and tight exit transition states, as well as insight into silicon- and sulfur-containing molecule formation pathways in deep space. Although neither of the non-deuterated species – the thiosilaformyl radical (HSiS) and silanethione (H 2 SiS) – have been observed in the interstellar medium (ISM) thus far, astrochemical models presented here predict relative abundances in the Orion Kleinmann-Low nebula to be sufficiently high enough for detection. 

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2. Regioreversed Carbosulfenylation of Fluoroalkenes via Nickel‐Mediated Radical Sorting

   https://doi.org/10.1002/anie.202509664  

   Zhu, Chuan; Liu, Qian; Wang, Nannan; Ma, Rui; Chen, Kai; Walsh, Patrick_J; Guo, Kai; Feng, Chao (June 2025, Angewandte Chemie International Edition)

   Abstract Carbosulfenylation of olefins represents an important class of reactions for the synthesis of structurally diverse organosulfur compounds. Previous studies typically yield 1,2‐regioselectivity. In the context of diversity‐oriented synthesis, accessing the regioreversed products is desirable, significantly broadening the scope of these reactions. In this study, we report a nickel‐catalyzed 2,1‐carbosulfenylation of trifluoromethyl‐ andgem‐difluoroalkenes, using free thiols and benzyl bromides as sulfur and carbon sources, respectively. The unusual regioselectivity observed is enabled by a “radical sorting” mechanism. The Ni catalyst activates benzyl bromide to generate a benzylic radical that undergoes hydrogen atom transfer (HAT) with the thiol to form a sulfur‐centered radical. The sulfur radical subsequently adds to the fluoroalkenes, resulting in an α‐fluoroalkyl C‐radical. This radical undergoes S_H2 with a Ni–CH₂Ar to form a C(sp³)─C(sp³) bond and quaternary center, ultimately producing valuable fluoroalkyl thioethers. Isotopic labeling experiments corroborate a hydrogen atom transfer (HAT) event within the working mechanism. 

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3. Sulfur radical formation from the tropospheric irradiation of aqueous sulfate aerosols

   https://doi.org/10.1073/pnas.2202857119  

   Cope, James D.; Bates, Kelvin H.; Tran, Lillian N.; Abellar, Karizza A.; Nguyen, Tran B. (September 2022, Proceedings of the National Academy of Sciences)

   The sulfate anion radical (SO 4 •– ) is known to be formed in the autoxidation chain of sulfur dioxide and from minor reactions when sulfate or bisulfate ions are activated by OH radicals, NO 3 radicals, or iron. Here, we report a source of SO 4 •– , from the irradiation of the liquid water of sulfate-containing organic aerosol particles under natural sunlight and laboratory UV radiation. Irradiation of aqueous sulfate mixed with a variety of atmospherically relevant organic compounds degrades the organics well within the typical lifetime of aerosols in the atmosphere. Products of the SO 4 •– + organic reaction include surface-active organosulfates and small organic acids, alongside other products. Scavenging and deoxygenated experiments indicate that SO 4 •– radicals, instead of OH, drive the reaction. Ion substitution experiments confirm that sulfate ions are necessary for organic reactivity, while the cation identity is of low importance. The reaction proceeds at pH 1–6, implicating both bisulfate and sulfate in the formation of photoinduced SO 4 •– . Certain aromatic species may further accelerate the reaction through synergy. This reaction may impact our understanding of atmospheric sulfur reactions, aerosol properties, and organic aerosol lifetimes when inserted into aqueous chemistry model mechanisms. 

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4. General method for iron-catalyzed multicomponent radical cascades–cross-couplings

   https://doi.org/10.1126/science.abj6005  

   Liu, Lei; Aguilera, Maria Camila; Lee, Wes; Youshaw, Cassandra R.; Neidig, Michael L.; Gutierrez, Osvaldo (October 2021, Science)

   Transition metal–catalyzed cross-coupling reactions are some of the most widely used methods in chemical synthesis. However, despite notable advantages of iron (Fe) as a potentially cheaper, more abundant, and less toxic transition metal catalyst, its practical application in multicomponent cross-couplings remains largely unsuccessful. We demonstrate 1,2-bis(dicyclohexylphosphino)ethane Fe–catalyzed coupling of α-boryl radicals (generated from selective radical addition to vinyl boronates) with Grignard reagents. Then, we extended the scope of these radical cascades by developing a general and broadly applicable Fe-catalyzed multicomponent annulation–cross-coupling protocol that engages a wide range of π-systems and permits the practical synthesis of cyclic fluorous compounds. Mechanistic studies are consistent with a bisarylated Fe(II) species being responsible for alkyl radical generation to initiate catalysis, while carbon-carbon bond formation proceeds between a monoarylated Fe(II) center and a transient alkyl radical. 

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5. Chamber studies of OH + dimethyl sulfoxide and dimethyl disulfide: insights into the dimethyl sulfide oxidation mechanism

   https://doi.org/10.5194/acp-24-1299-2024  

   Goss, Matthew B; Kroll, Jesse H (January 2024, Atmospheric Chemistry and Physics)

   Abstract. The oxidation of dimethyl sulfide (DMS) in the marine atmosphere represents an important natural source of non-sea-salt sulfate aerosol, but the chemical mechanisms underlying this process remain uncertain. While recent studies have focused on the role of the peroxy radical isomerization channel in DMS oxidation, this work revisits the impact of the other channels (OH addition and OH abstraction followed by bimolecular RO2 reaction) on aerosol formation from DMS. Due to the presence of common intermediate species, the oxidation of dimethyl sulfoxide (DMSO) and dimethyl disulfide (DMDS) can shed light on these two DMS reaction channels; they are also both atmospherically relevant species in their own right. This work examines the OH oxidation of DMSO and DMDS, using chamber experiments monitored by chemical ionization mass spectrometry and aerosol mass spectrometry to study the full range of sulfur-containing products across a range of NO concentrations. The oxidation of both compounds is found to lead to rapid aerosol formation (which does not involve the intermediate formation of SO2), with a substantial fraction (14 %–47 % S yield for DMSO and 5 %–21 % for DMDS) of reacted sulfur ending up in the particle phase and the highest yields observed under elevated NO conditions. Aerosol is observed to consist mainly of sulfate, methanesulfonic acid, and methanesulfinic acid. In the gas phase, the NOx dependence of several products, including SO2 and S2-containing organosulfur species, suggest reaction pathways not included in current mechanisms. Based on the commonalities with the DMS oxidation mechanism, DMSO and DMDS results are used to reconstruct DMS aerosol yields; these reconstructions roughly match DMS aerosol yield measurements from the literature but differ in composition, underscoring remaining uncertainties in sulfur chemistry. This work indicates that both the abstraction and addition channels contribute to rapid aerosol formation from DMS and highlights the need for more study into the fate of small sulfur radical intermediates (e.g., CH3S, CH3SO2, and CH3SO3) that are thought to play central roles in the DMS oxidation mechanism. 

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