C₂H₅NO Isomers: From Acetamide to 1,2-Oxazetidine and Beyond

Area of Science:

• Astrochemistry
• Computational Chemistry
• Chemical Bonding

Background:

• The interstellar medium (ISM) contains complex organic molecules, but the formation pathways of many isomers, such as acetamide (C2H5NO), remain debated.
• Existing chemical literature inadequately covers many C2H5NO isomers, limiting computational chemistry and AI applications in predicting chemical bonding.

Purpose of the Study:

• To document the properties of various C2H5NO isomers, including high-energy dipolar species.
• To identify potential new candidates for detection in the ISM and assess their detectability.
• To propose a plausible formation mechanism for ethanimidic acid, a precursor to acetamide.

Main Methods:

• Theoretical characterization of C2H5NO isomers.
• Analysis of potential formation pathways in the ISM.
• Computational modeling of reaction mechanisms, including energy barriers.

Main Results:

• Characterization of multiple C2H5NO isomers, with acetamide identified as the most stable.
• Only two C2H5NO isomers have been detected in the ISM; several others are proposed as candidates.
• A 1,3-[H]-transfer from ethanimidic acid to acetamide is feasible despite a significant energy barrier.
• A potential acid-induced, autocatalytic formation of ethanimidic acid from water and acetonitrile on ice grains is proposed.

Conclusions:

• This work expands the understanding of C2H5NO isomers and their potential presence in the ISM.
• The proposed formation pathway for ethanimidic acid offers a plausible route to acetamide in interstellar environments.
• The comprehensive data on C2H5NO isomers can enhance machine learning models for chemical bonding and AI applications.