Mo, O. published the artcileProtonation energies and tautomerism of azoles. Basis set effects, HPLC of Formula: 63598-71-0, the publication is Journal of Physical Chemistry (1986), 90(22), 5597-604, database is CAplus.
The structure, protonation energies, tautomerism, and vertical ionization potentials of several azoles are examined by ab initio calculations using different basis sets ranging from minimal to split valence plus polarization. Minimal basis tends to overestimate all N-N and C-N lengths. Though, in general, 3-21G geometries are close to 6-31G structures, the former basis does not always correct the deficiencies of minimal basis. In general, 6-31G structures agree with the exptl. ones. Azoles with more than one basic N atom protonate preferentially on imidazolic rather than on pyrazolic type N atoms. Minimal basis significantly overestimates absolute protonation energies, but the deviations observed for relative protonation energies are not always of the same sign. Both 3-21G and 6-31G absolute protonation energies are almost equal and much smaller than those obtained at the minimal basis level. The inclusion of polarization functions in the basis (6-31G*//6-31G calculations) leads to a further decrease in absolute protonation energies which depends on the degree of anisotropy of the charge distribution of the center which undergoes protonation. The relative stabilities of the tautomers change with the basis set. These changes are particularly important for triazolium and tetrazolium cations, as well as for pyrazole and imidazole. For 1,2,4-triazoles, tetrazoles, and 1H-pentazole Koopman’s theorem predicts the wrong ionization potential.
Journal of Physical Chemistry published new progress about 63598-71-0. 63598-71-0 belongs to triazoles, auxiliary class Triazole, name is 4H-1,2,4-Triazole, and the molecular formula is C2H3N3, HPLC of Formula: 63598-71-0.
Referemce:
https://en.wikipedia.org/wiki/1,2,3-Triazole,
Triazoles – an overview | ScienceDirect Topics