ELECTRON DENSITY DISTRIBUTION IN HETEROCYCLIC SYSTEMS WITH TWO VICINAL NITROGEN ATOMS. III. DIPOLE MOMENTS OF SOME ALKYL, ARYL, AND NITRO PYRAZOLE DERIVATIVES

Abstract

Dipole moments of 13 alkyl and aryl derivatives of pyrazole are determined. It is found that fundamentally it is the pyrazole ring that determines the values of these dipole moments. The phenyl group behaves as a weak electron donor with respect to the pyrazole ring. It is shown that under the action of powerful electron-accepting substituents, such as the nitro group, the electron cloud of the pyrazole ring is polarized toward the electron acceptor. Authors: S. A. Giller, I. B. Mazheika, I. I. Grandberg. English Translation in Chemistry of Heterocyclic Compounds , 1965, 1 (1), pp 72-75 http://link.springer.com/article/10.1007/BF01168926