ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

A computational study of the propargylimine (PGIM) formation mechanism in the interstellar medium (ISM)

Lucas Coutinho, Renato Veríssimo de Oliveira, and Norberto Monteiro

Departamento de Química Analítica E Físico Química, Centro de Ciências, Universidade Federal Do Ceará, Fortaleza, Brazil

E-mail: norbertokv@ufc.br

Received: 14 June 2023  Accepted: 25 November 2023

Abstract:

Studies on the theoretical quantum chemistry of reaction mechanisms are essential to understand the formation pathways of simple and complex organic molecules in the interstellar medium (ISM). In this study, we used computational chemistry to investigate the formation pathways of the interstellar molecule propargylimine (2-propyn-1-imine, HC≡C–CH =NH) using Strecker synthesis. Our proposal for a two-step mechanism of PGIM synthesis involved the WB97XD/aug-ccpVTZ level of theory in the gas phase at temperatures of 10 and 298 K. Based on the energetic data, the potential energy surface (PES) indicates an S_N2 mechanism for the first step and an E2 elimination mechanism for the second step, with a lower energy barrier considering the first step. The results suggest that the PGIM product is thermodynamically more stable than the reactants. Furthermore, topological data from QTAIM and ELF agree with the energetic data. Therefore, these results demonstrate that PGIM can be formed through two-step Strecker synthesis in a possible interstellar environment.

Keywords: Interstellar medium; PGIM; DFT; Mechanism; QTAIM; ELF

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-023-03256-7

Chemical Papers 78 (4) 2509–2518 (2024)