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Sulfur- and silicon-containing molecules are omnipresent in interstellar and circumstellar environments, but their elementary formation mechanisms have been obscure. These routes are of vital significance in starting a chain of chemical reactions ultimately forming (organo) sulfur molecules—among them precursors to sulfur-bearing amino acids and grains. Here, we expose via laboratory experiments, computations, and astrochemical modeling that the silicon-sulfur chemistry can be initiated through the gas-phase reaction of atomic silicon with hydrogen sulfide leading to silicon monosulfide (SiS) via nonadiabatic reaction dynamics. The facile pathway to the simplest silicon and sulfur diatomic provides compelling evidence for the origin of silicon monosulfide in star-forming regions and aids our understanding of the nonadiabatic reaction dynamics, which control the outcome of the gas-phase formation in deep space, thus expanding our view about the life cycle of sulfur in the galaxy.
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Simultaneous synthesis of thioesters and iron–sulfur clusters in water: two universal components of energy metabolism
Thioesters are important intermediates in both synthetic organic and biosynthetic reaction pathways. Here we show that thioesters can be synthesized in an aqueous reaction between thioacetate and thiols. The reaction can be coupled to a second reaction between sulfide and either ferrous or ferric iron, which drives the reaction forward. We furthermore demonstrate that sulfide released during thioester formation can be used in the synthesis of peptide bound [Fe–S] clusters, which like thioesters, are ancient components of metabolism. Together our results reveal a primordial linkage between high-energy ester formation and redox chemistry.
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- Award ID(s):
- 1724300
- PAR ID:
- 10236996
- Date Published:
- Journal Name:
- Chemical Communications
- Volume:
- 56
- Issue:
- 80
- ISSN:
- 1359-7345
- Page Range / eLocation ID:
- 11989 to 11992
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract We report the formation of minerals from the tochilinite-valleriite group (TVG) during laboratory serpentinization experiments conducted at 300 and 328 °C. Minerals in the TVG are composed of a mixture of sulfide and hydroxide layers that can contain variable proportions of Fe, Mg, Cu, Ni, and other cations in both layers. Members of this group have been observed as accessory minerals in several serpentinites, and have also been observed in association with serpentine minerals in meteorites. To our knowledge, however, TVG minerals have not previously been identified as reaction products during laboratory simulation of serpentinization. The serpentinization experiments reacted olivine with artificial seawater containing 34S-labeled sulfate, with a small amount of solid FeS also added to the 300 °C experiment. In both experiments, the predominant reaction products were chrysotile serpentine, brucite, and magnetite. At 300 °C, these major products were accompanied by trace amounts of the Ni-bearing TVG member haapalaite, Ni,Fe-sulfide (likely pentlandite), and anhydrite. At 328 °C, valleriite occurs rather than haapalaite and the accompanying Ni,Fe-sulfide is proportionally more enriched in Ni. Reduction of sulfate by H2 produced during serpentinization evidently provided a source of reduced S that contributed to formation of the TVG minerals and Ni,Fe-sulfides. The results provide new constraints on the conditions that allow precipitation of tochilinite-valleriite group minerals in natural serpentinites.more » « less
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1039/d0cc04078a
