Fluoropyrazoles: An ab initio study

Quantum mechanic calculations have been done at the RHF and MP2 levels with the STO-3G, 6-31G**, 6-311G** basis sets on pyrazole itself and seven N-un substituted C-fluoropyrazoles. These calculations have been used to discuss the molecular structure of these compounds in relation to their aromaticit y. The corresponding H-1, C-13, N-15 and F-19 chemical shifts were calculat ed using the GIAO perturbation method.