Hydrazine complexes with formic acid formed in the N₂H₄—HCOOH—HCOO⁻ system in the presence of KOBu^t—DMSO superbase: a quantum chemical study

Hydrazine complexes with formic acid, free formate ion, and a potassium formate complex 5DMSO · K⁺HCOO⁻ formed in the system N₂H₄—HCOOH—K⁺HCOO⁻— DMSO were studied. The possibility for hydrazine formylation to occur was assessed. According to calculations, a [N₂H₆(HCOO)₃]⁻ complex is formed in the system in question. The calculated kinetic and thermodynamic characteristics suggest that hydrazine formylation can occur in this complex. The reaction is reversible; as a consequence, the reaction medium can contain both the [N₂H₆(HCOO)₃]⁻ complex and formylhydrazine. All calculations were carried out using the B2PLYP-D2/6-311+G**//B3LYP/6-31+G* approach with inclusion of solvation effects in terms of the IEFPCM continuum model with DMSO as solvent and with explicit inclusion of the nearest solvation shell of the potassium cation (five DMSO molecules).