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Dearomatization drives complexity generation in freshwater organic matter.
Li, Siyu; Harir, Mourad; Bastviken, David; Schmitt-Kopplin, Philippe; Gonsior, Michael; Enrich-Prast, Alex; Valle, Juliana; Hertkorn, Norbert.
Afiliação
  • Li S; Research Unit Analytical Biogeochemistry (BGC), Helmholtz Munich, German Research Center for Environmental Health, Neuherberg, Germany.
  • Harir M; Research Unit Analytical Biogeochemistry (BGC), Helmholtz Munich, German Research Center for Environmental Health, Neuherberg, Germany.
  • Bastviken D; Chair of Analytical Food Chemistry, Technische Universität München, Freising-Weihenstephan, Germany.
  • Schmitt-Kopplin P; Department of Thematic Studies - Environmental Change, Linköping University, Linköping, Sweden.
  • Gonsior M; Research Unit Analytical Biogeochemistry (BGC), Helmholtz Munich, German Research Center for Environmental Health, Neuherberg, Germany.
  • Enrich-Prast A; Chair of Analytical Food Chemistry, Technische Universität München, Freising-Weihenstephan, Germany.
  • Valle J; Chesapeake Biological Laboratory, University of Maryland Center for Environmental Science, Solomons, MD, USA.
  • Hertkorn N; Department of Thematic Studies - Environmental Change, Linköping University, Linköping, Sweden.
Nature ; 628(8009): 776-781, 2024 Apr.
Article em En | MEDLINE | ID: mdl-38658683
ABSTRACT
Dissolved organic matter (DOM) is one of the most complex, dynamic and abundant sources of organic carbon, but its chemical reactivity remains uncertain1-3. Greater insights into DOM structural features could facilitate understanding its synthesis, turnover and processing in the global carbon cycle4,5. Here we use complementary multiplicity-edited 13C nuclear magnetic resonance (NMR) spectra to quantify key substructures assembling the carbon skeletons of DOM from four main Amazon rivers and two mid-size Swedish boreal lakes. We find that one type of reaction mechanism, oxidative dearomatization (ODA), widely used in organic synthetic chemistry to create natural product scaffolds6-10, is probably a key driver for generating structural diversity during processing of DOM that are rich in suitable polyphenolic precursor molecules. Our data suggest a high abundance of tetrahedral quaternary carbons bound to one oxygen and three carbon atoms (OCqC3 units). These units are rare in common biomolecules but could be readily produced by ODA of lignin-derived and tannin-derived polyphenols. Tautomerization of (poly)phenols by ODA creates non-planar cyclohexadienones, which are subject to immediate and parallel cycloadditions. This combination leads to a proliferation of structural diversity of DOM compounds from early stages of DOM processing, with an increase in oxygenated aliphatic structures. Overall, we propose that ODA is a key reaction mechanism for complexity acceleration in the processing of DOM molecules, creation of new oxygenated aliphatic molecules and that it could be prevalent in nature.
Assuntos

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Carbono / Água Doce País/Região como assunto: Europa Idioma: En Revista: Nature Ano de publicação: 2024 Tipo de documento: Article País de afiliação: Alemanha

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Carbono / Água Doce País/Região como assunto: Europa Idioma: En Revista: Nature Ano de publicação: 2024 Tipo de documento: Article País de afiliação: Alemanha