Global Reaction Route Mapping of C3H2O: Isomerization Pathways, Dissociation Channels, and Bimolecular Reaction with a Water Molecule

Abstract

A comprehensive theoretical investigation of the C₃H₂O potential energy surface (PES) was conducted, revealing 30 equilibrium structures (EQs), 128 transition state structures (TSs), and 35 direct dissociation channels (DCs), establishing a global reaction network comprising 101 isomerization pathways and dissociation channels. Particular focus was placed on the five most stable isomers, H₂CCCO (EQ3), OC(H)CCH (EQ7), H-c-CC(O)C-H (EQ0), HCC(H)CO (EQ1), and HO-c-CCC-H (EQ12), and their reactions with water molecules. Multicomponent artificial force-induced reaction (MC-AFIR) calculations were employed to study bimolecular collisions between H₂O and these stable isomers. The product distributions revealed isomer-specific reactivity patterns: EQ3 and EQ7 predominantly formed neutral species at high collision energies, EQ0 produced both ionic and neutral species, while EQ1 and EQ12 exhibited more accessible reaction pathways at lower collision energies with a propensity for spontaneous isomerization. Born-Oppenheimer Molecular Dynamics (BOMD) simulations complemented these findings, suggesting several viable products emerge from reactions with water molecules, including HCCC(OH)₂H (EQ7 + H₂O), OCCHCH₂OH (EQ1 + H₂O), and HO-c-CC(H)C(OH)-H (EQ12 + H₂O). This investigation elucidates the intrinsic relationships between isomers and their potential products, formed through biomolecular collisions with water molecules, establishing a fundamental framework for future conformational and reactivity studies of the C₃H₂O family.

Keywords: C3H2O; bimolecular reactions; conformational explorations; dissociation pathways; isomerization.

Figure 1

Isomerization pathways among the five most thermodynamically stable C₃H₂O isomers. Cyclopropenone (EQ0) served as the parent structure for conformational exploration. Isomerization processes are represented by directional arrows, with red arrows indicating transitions toward less stable isomers, and green arrows denoting transitions toward more stable configurations. Pathways of equivalent mechanistic significance are differentiated by dashed and solid lines. Atoms colored red represent oxygen, gray represent carbon, and white represent hydrogen.

Figure 2

TS-mediated dissociation channels represented as EQa-TSb-DC pathways. Atoms colored red represent oxygen, gray represent carbon, and white represent hydrogen.

Figure 3

Direct dissociation channels for C₃H₂O isomers. The notation EQm-DCn indicates the pathway from EQm to DCn. Atoms colored red represent oxygen, gray represent carbon, and white represent hydrogen.

Figure 4

Relative energy distributions of EQ, TS, and DC structures at different levels of theory, with EQ0 as the reference.

Figure 5

Potential distributions resulting from collisions between EQ3 (H₂CCCO) and H₂O molecules. Formation ratios of MC-AFIR products with distinct artificial forces are shown in different colors.

Figure 6

Potential distributions resulting from collisions between EQ7 (OC(H)CCH) and H₂O molecules. Formation ratios of MC-AFIR products with distinct artificial forces are shown in different colors.

Figure 7

Potential distributions resulting from collisions between EQ0 (H-c-CC(O)C-H) and H₂O molecules. Formation ratios of MC-AFIR products with distinct artificial forces are shown in different colors.

Figure 8

Potential distributions resulting from collisions between EQ1 (HCC(H)CO) and H₂O molecules. Formation ratios of MC-AFIR products with distinct artificial forces are shown in different colors.

Figure 9

Potential distributions resulting from collisions between EQ12 (HO-c-CCC-H) and H₂O molecules. Formation ratios of MC-AFIR products with distinct artificial forces are shown in different colors.