Oxidative polymerization of organic compounds in the presence of iron-bearing minerals: implications for organic preservation on Mars
File(s)
Published version
Author(s)
Gumbley, John J
Lau, Nizana
Watson, Jonathan S
Sephton, Mark A
Type
Journal Article
Abstract
Exploring for evidence of life on Mars involves detecting organic signals that may reflect the prebiotic processes which led to the emergence of life or the molecular remnants of biology. For detection at the present day, organic signals, whether abiotic or biological in origin, must have survived over periods that extend to billions of years. The terrestrial fossil organic record indicates that polymerization enhances preservation over time. One polymer-forming process that is observed on Earth, but may be especially relevant to Mars, is oxidative polymerization, where organic compounds are assembled into polymers or macromolecules by reaction with oxidants. On Earth, oxidative polymerization commonly uses atmospheric oxygen, but mineral oxidants can also promote the reaction. Oxidized iron can act as a polymerizing agent for organic compounds and is widespread on the surface of Mars. For instance, the iron oxyhydroxide goethite (α-FeO(OH)) has been detected on Mars by spectrometers carried by orbiters and rovers. This study examines whether Fe(III)-bearing minerals under Mars-relevant conditions can promote oxidative coupling of simple aromatic compounds. Our results show that in environments representative of the Martian near surface, the ferric/iron(III) content of goethite causes oxidative coupling of 2-naphthol (C10H8O) to its dimer, 1,1′-bi-2-naphthol (BINOL) and, under certain conditions, to larger fused-ring aromatic products. Recognition of the effective polymerization of organic compounds in the presence of a mineral that is common on Mars provides direction for the ongoing search for preserved Martian organic matter when selection of landing sites or sampling locations is taking place.
Date Issued
2026-06-18
Date Acceptance
2026-05-06
Citation
ACS Earth and Space Chemistry, 2026, 10 (6), pp.1493-1506
ISSN
2472-3452
Publisher
American Chemical Society (ACS)
Start Page
1493
End Page
1506
Journal / Book Title
ACS Earth and Space Chemistry
Volume
10
Issue
6
Copyright Statement
© 2026 The Authors. Published by American Chemical Society. This publication is licensed under CC-BY 4.0.
License URL
Identifier
10.1021/acsearthspacechem.6c00016
Subjects
Metrics & More Article Recommendations goethite
2-naphthol
BINOL
abiotic polymerization
UV irradiation
mineral−organic interactions
mars geochemistry
Publication Status
Published
Date Publish Online
2026-05-26