DFT and G2MP2 calculations of the N-N bond dissociation enthalpies and enthalpies of formation of hydrazine, monomethylhydrazine and symmetrical and unsymmetrical dimethylhydrazine

In a combined DFT (B3LYP) and G2MP2 theoretical study the following enthalpies of formation (H°f) and bond dissociation enthalpies (BDE) for hydrazine, methylhydrazine (MMH), 1,1-dimethylhydrazine (UDMH) and 1,2-dimethylhydrazine (SDMH) were determined: BDE/kJ mol -1: N2H4, 278 ± 4; MMH, 272 ± 4; UDMH, 259 ± 12; SDMH, 272 ± 12. H°f/kJ mol-1: N2H4, 95 ± 6; MMH, 94 ± 4; UDMH, 80 ± 4; SDMH, 91 ± 4. The bond enthalpy for the N-N bond in hydrazine amounts to BE (N-N, H2N - NH2) = 159 ± 4 kJ mol-1.