Molecule 2 (imine acetaldehyde) exhibits similar trends, with the out-ap conformation being the most stable. This conformation has energy differences of 1.20, 5.53, and 1.92 kcal/mol relative to the in-ap, out-sp, and in-sp conformations, respectively. These results are consistent with previous theoretical studies . Interestingly, the out-sp and in-sp conformations were identified as intermediates in the CH 2 + HCNO reaction pathway, with the in-ap conformation serving as the final product . This underscores the thermodynamic preference for antiperiplanar conformations and their potential relevance in interstellar chemical processes.