PRODUCTION OF Cα-ALANYL RADICAL AND VINYLAMINE IN THE REACTION H + α-ALANINE IN SOLID p-H₂ AND ITS IMPLICATIONS IN ASTROCHEMISTRY

Joshi, Prasad Ramesh

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Title

PRODUCTION OF Cα-ALANYL RADICAL AND VINYLAMINE IN THE REACTION H + α-ALANINE IN SOLID p-H₂ AND ITS IMPLICATIONS IN ASTROCHEMISTRY

Author(s)

Joshi, Prasad Ramesh

Contributor(s)

Lee, Yuan-Pern

Issue Date

2023-06-20

Keyword(s)

Radicals

Abstract

Amino acids, key building blocks of protein, gained enormous attention in interstellar chemistry because they were detected in comets and meteorites; these observations provided strong evidence for the cosmic origin of amino acids on Earth. However, detailed investigations regarding their formation and reactivities with interstellar relevant species under cosmic-like conditions are scarce. We utilized the characteristics of para-hydrogen (p-H₂), which served as a quantum-solid matrix host and a medium for efficient hydrogen-atom reaction, to investigate the reaction between α-alanine [H₂NCH(CH₃)C(O)OH] and H atoms at 3.2 K. To produce H atoms, we performed UV photolysis at 365 nm on a matrix co-deposited with a mixture of H₂NCH(CH₃)C(O)OH/p-H₂ and Cl₂ to produce Cl atoms, followed by infrared irradiation to promote the Cl + H₂ (ν = 1) → H + HCl reaction. Among four different hydrogen-containing moieties of H₂NCH(CH₃)C(O)OH, H abstraction on the -CH moiety to produce Cα-alanyl radical [H₂N • C(CH₃)C(O)OH] from the conformer with the least energy is the most favorable. This radical plays a vital role in the asymmetric synthesis of complex organic molecules. In parallel, possibly H abstraction on both -C(O)OH and CH₃ moieties led to the fragmentation to produce vinylamine (NH₂CH = CH₂) and CO₂ through the second-most favorable channel. Recently, vinylamine has been detected in the interstellar medium.ᵃ These assignments were supported by isotopic substitution experiments and a comparison of experimental numbers of possible products predicted with the B3LYP/aug-cc-pVTZ method.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

Text

Language

eng

Handle URL

https://hdl.handle.net/2142/122313

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