# Low temperature formation of pyridine and (iso)quinoline via neutral neutral reactions

**Authors:** Zhenghai Yang, Chao He, Shane J. Goettl, Alexander M. Mebel, Paulo F. G. Velloso, Márcio O. Alves, Breno R. L. Galvão, Jean-Christophe Loison, Kevin M. Hickson, Michel Dobrijevic, Xiaohu Li, Ralf I. Kaiser  
**arXiv:** [2406.16945](https://arxiv.org/abs/2406.16945)  
**Date:** 2024-06-19  
**Summary page:** https://www.summarizepaper.com/en/paper/2406.16945v1/

## Key points

- Aromatic molecules are crucial in prebiotic chemistry for DNA and RNA nitrogen bases.
- Pathways to pyridine, pyridinyl, and (iso)quinoline have been elusive despite identification of around 300 molecules in extraterrestrial environments.
- Gas-phase formation of methylene amidogen and cyanomethyl radicals has been demonstrated through molecular beam studies and electronic structure calculations.
- Researchers have identified a complex chain of reactions that can synthesize pyridine, pyridinyl, and (iso)quinoline from H2CN and H2CCN at levels of up to 75% in Taurus Molecular Cloud (TMC 1) and Titan's atmosphere.
- These findings challenge existing theories about the origin of prebiotic molecules in our Galaxy.

## Summary

Aromatic molecules play a crucial role in prebiotic chemistry as they are considered essential precursors to DNA and RNA nitrogen bases. Despite the identification of around 300 molecules in extraterrestrial environments, the pathways to pyridine (C5H5N), pyridinyl (C5H4N), and (iso)quinoline (C9H7N) – the simplest representatives of mono and bicyclic aromatic molecules carrying nitrogen – have remained elusive. This study presents compelling evidence on the gas-phase formation of methylene amidogen (H2CN) and cyanomethyl (H2CCN) radicals through molecular beam studies and electronic structure calculations. By modeling the chemistries of Taurus Molecular Cloud (TMC 1) and Titan's atmosphere, researchers have identified a complex chain of reactions that can synthesize pyridine, pyridinyl, and (iso)quinoline from H2CN and H2CCN at levels of up to 75%. These findings provide unique insights into the origins of DNA and RNA nitrogen bases in hydrocarbon-rich extraterrestrial environments, challenging existing theories about the origin of prebiotic molecules in our Galaxy. The study titled "Low-temperature formation of pyridine and (iso)quinoline via neutral-neutral reactions" was conducted by Zhenghai Yang, Chao He, Shane J. Goettl, Alexander M. Mebel, Paulo F. G. Velloso, Márcio O. Alves, Breno R. L. Galvão, Jean-Christophe Loison, Kevin M. Hickson, Michel Dobrijevic,Xiaohu Li,and Ralf I.Kaiser from various institutions including the Department of Chemistry at U...