Structure moléculaire et propriétés moléculaires de quatre isomères de formule C8H10N4

The molecular structures of the three Meyer isomers 3-methyl-3-(5′-amino-3′-methyl-l-pyrazolyl)acrylonitrile; acetylacetonitrile azine; 2,5-dimethyl-7-aminopyrazolo1,5-a]pyrimidine] have been compared with that of the fourth isomer, 2,7-dimethyl-5-amino-pyrazolo1,5-a]pyrimidine. The CNDO/2 and CNDO/S calculations utilizing these geometries have been accomplished. These include electronic transitions, dipole moments, ionisation potentials, charge densities, bond ordres and total energies. The calculated values have been compared to some experimental data. Uv spectra, ¹³C chemical shifts, ¹H-¹H coupling constants and relative stability of the four isomers are included.