L. Infantes, C. Foces-Foces, R. Claramunt
May 1, 1999
Citations
0
Influential Citations
15
Citations
Journal
Journal of Heterocyclic Chemistry
Abstract
The crystal structure determination of 3,5-dimethyl-4-aminopyrazole (3) and of 3(5)-aminopyrazolium picrate salt (5a) have been undertaken. The packing in 3 is characterized by the formation of sheets in which the N-H of the pyrazole and one H atom of the amino group are involved. The remaining HB donor interconnects sheets. In 5a, the anions and the cations are linked by a two-dimensional network of hydrogen bonds in the ab plane. Each N-H and C-H in the cation are involved in hydrogen interactions with the O atoms of the anion. Ab initio molecular orbital methods at the HF and B3LYP levels using a 6–31G** basis set have been carried out to compare the relative stability of the tautomeric forms of the 3(5)-aminopyrazolium and 4-aminopyrazolium cations.