Pathways of the reactions of nucleophilic addition of H2O and HF molecules to formaldehyde in the gas phase and in the complex with formic acid: ab initio calculations

Article abstract of DOI:10.1007/BF02494259

The gradient pathways of the reactions of nucleophilic addition of H₂O and HF molecules to formaldehyde in the gas phase and in the XH...H₂CO...HC(O)OH complex (X = OH, F) were calculated by the ab initio RHF/6-31G**, MP2(fc)/6-31G**, and MP2(full)/6-311++G** methods. Both reactions proceed concertedly. The formation of H-bonded bimolecular pre-reaction complexes is the initial stage of the gas-phase reactions; at the same time, no indications of the formation of stable π-complexes were found on the potential energy surfaces of systems under study. The calculated energy barriers to the gas-phase reactions exceed 40 kcal mol^-1, while those to reactions in the complex XH...H₂CO...HC(O)OH (X = OH, F) become more than halved.