Mackinawite‐Supported Reduction of C₁ Substrates into Prebiotically Relevant Precursors

Abstract

Mackinawite has unique structural properties and reactivities when compared to other iron sulfides. Herein we provide evidence for the mackinawite‐supported reduction of KCN into various reduced compounds under primordial conditions. We proposed a reaction mechanism based on the nucleophilic attack by the deprotonated mackinawite ‐SH surface groups at the carbon atom of HCN. The initial binding of the substrate and the subsequent reduction events are supported by DFT calculations and further experiments using other substrates, such as KSCN, KOCN and CS2. Until now, conversion of CN− into CH4 and NH3 has been limited to nitrogenase cofactors or molecular Fe‐CN complexes. Our study provides evidence for mackinawite‐supported cleavage of the C−N bond under ambient conditions, which opens new avenues for investigation of other substrates for mackinawite‐supported reactions while shedding light on the relevance of this type of reaction to the origin of life on Earth.

Facile Synthesis and Characterization of Pure Tochilinite‐like Materials from Nanoparticulate FeS

“…Layered hybrid materials have attracted some attention as functional materials for electronic, magnetic and optical applications and tunable tochilinite may be an interesting candidate for future developments [7–11] . Additionally, it may be a suitable mediator for prebiotically relevant reactions as has been suggested and experimentally shown for other iron sulfides [12–16] . Besides being delivered by meteoritic impacts, tochilinite forms from iron sulfides in basic anoxic environments and might have been quite common on the early earth [17,18] .…”

“…[7][8][9][10][11] Additionally, it may be a suitable mediator for prebiotically relevant reactions as has been suggested and experimentally shown for other iron sulfides. [12][13][14][15][16] Besides being delivered by meteoritic impacts, tochilinite forms from iron sulfides in basic anoxic environments and might have been quite common on the early earth. [17,18] Synthetic tochilinite has been produced before, however, without the ability to control the iron ion distribution and the samples have always been contaminated by side products like pyrrhotite, pyrite and magnetite.…”

A prebiotic genetic alphabet as an early Darwinian ancestor for pre-RNA evolution

“…The former is based on phylogenetic analysis to deduce the simplest cellular life form called LUCA (the Last Universal Common Ancestor), which is thought to be a compartmentalized organism with a complex metabolic and catalytic network, along with a sophisticated genetic system 5,6 . The bottom-up approach relies on studying the emergence of life from simpler interacting organic chemicals 7–9 . Understanding the chemical emergence of life through LUCA poses the following two prominent questions, 1) Which biomolecule came about first?…”

Enzymatic Fischer–Tropsch-Type Reactions

“…With this suggestion in mind, most of the previously discussed functionalities of metal sulfides can now be considered under conditions that allow H 2 O to be frequently absent, which opens up new avenues for studies of additional substrates that could emerge from photochemistry in the early atmosphere. Along this line of investigation, HCN was shown to be reduced by mackinawite to a number of prebiotically relevant compounds, including greigite, CH 4 , C 1 –C 4 thiols, NH 3 , and CH 3 CHO . The observation of CH 3 CHO formation is especially promising, as this organic C 2 compound was previously used for the synthesis of deoxyribonucleotides from purine/pyrimidine bases and sugar-forming precursors …”

“…Along this line of investigation, HCN was shown to be reduced by mackinawite to a number of prebiotically relevant compounds, including greigite, CH 4 , C 1 −C 4 thiols, NH 3 , and CH 3 CHO. 234 The observation of CH 3 CHO formation is especially promising, as this organic C 2 compound was previously used for the synthesis of deoxyribonucleotides from purine/pyrimidine bases and sugar-forming precursors. 235 Taken together, the terrestrial OOL most likely followed an initial chemical evolution of biologically relevant precursors from small substrates, such as minerals and reduced volcanic exhalations, and natural energy sources, such as photochemistry and lightning.…”