Theoretical Examination of O(¹D) Insertion Reactions to Form Methanediol, Methoxymethanol, and Aminomethanol

A computational study of O­(¹D) insertion reactions with methanol (CH₃OH), dimethyl ether (CH₃OCH₃), and methyl amine (CH₃NH₂) was performed to guide laboratory investigations of the insertion product molecules methanediol (HOCH₂OH), methoxymethanol (CH₃OCH₂OH), and aminomethanol (HOCH₂NH₂), respectively. The minimum energy and higher energy conformer geometries of the products were determined at the MP2/aug-cc-pVTZ level of theory, and CCSD­(T)/aug-cc-pVTZ calculations were performed on the reactants, products, and transitions states to examine the insertion reaction energetics. Torsional barriers for internal motion in methanediol, methoxymethanol, and aminomethanol were also determined. It was found that O­(¹D) insertion into the C–H bond was the most energetically favored reaction pathway, proceeding through a direct and barrierless insertion mechanism. The pathways of O­(¹D) insertion into N–H or O–H bonds are also possible, though these reactions are less energetically favored, as they proceed through an association product intermediate before proceeding to the insertion products. Predictions are presented for the pure rotational spectra for the methanediol, methoxymethanol, and aminomethanol products based on the determined molecular parameters. These results provide an excellent starting point to guide laboratory spectral studies of the products