C2-addition patterns emerging from acetylene and nickel sulfide in simulated prebiotic hydrothermal conditions

Abstract

Chemical complexity is vital not only for the origin of life but also for biological evolution. The chemical evolution of a complex prebiotic mixture containing acetylene, carbon monoxide (CO), and nickel sulfide (NiS) has been analyzed with mass spectrometry as an untargeted approach to reaction monitoring. Here we show through isotopic 13C-labelling, multiple reaction products, encompassing diverse CHO and CHOS compounds within the complex reaction mixture. Molecules within the same chemical spaces displayed varying degrees of 13C-labelling, enabling more robust functional group characterization based on targeted investigations and differences in saturation levels among the described classes. A characteristic C2-addition pattern was detected in all compound classes in conjunction with a high diversity of thio acids, reminiscent of extant microbial C2-metabolism. The analysis involved a time-resolved molecular network, which unveiled the behavior of sulfur in the system. At the onset of the reaction, early formed compounds contain more sulfur atoms compared to later emerging compounds. These results give an essential insight into the still elusive role of sulfur dynamics in the origin of life. Moreover, our results provide temporally resolved evidence of the progressively increasing molecular complexity arising from a limited number of compounds.

Role of Acetylene in the Chemical Evolution of Carbon Complexity

“…The evolution of a complex prebiotic mixture containing C 2 H 2 , CO, and NiS was also shown in recent works by Sobotta et al and Diederich et al A suspension of precipitated NiS was shown to convert acetylene and carbon monoxide into a set of C2–4 products. Moreover, the authors demonstrated the formation of a homologous series of thioacids upon repeated addition of C 2 to the resulting compounds via acetylene.…”