Abstract

Abdulfatai, A. Siaka^1*, Uzairu Adamu², Idris Sulaiman² and Abba Hamza²

DOI : http://dx.doi.org/10.13005/ojc/310416

Mechanism of formations of (E)-2-(1-phenylethylidene)hydrazinecarboxamide, 2-cyclohexyldenehydrazinecarboxamide, (Z)-2-(1-phenylpropan-2-ylidene)hydrazinecarboxamide, (Z)-2-(hexan-2-ylidene)hydrazinecarboxamide and (E)-2-((E)phenylallylidene)hydrazinecarboxamide has been investigated using density functional theory (B3LYP/6-311+G**). The mechanism was found to involve four elementary steps comprising one intermediate and two transition states. The study indicates a two-step reaction pathway, comprising an intermediate and two activated complexes for all the compounds.  The mechanism involves two transition (bimolecular and unimolecular) and consecutive (bimolecular and unimolecular) schemes. The formation was found to occur sequentially; a fast pre-equilibrium between the reactants and the prereactive complex is established, followed by an internal rearrangement leading to elimination of a water molecule. The thermodynamic data were obtained for the stationary points and the kinetic study shows the unimolecular consecutive step to be the rate determining step in all the formation mechanisms. A general rate law was also established for the formation pathways.

pre-equilibrium; intermediate; stationary points; bimolecular and thermodynamic

[ View HTML Full Text]