Acyl nitroxides. Part 4. Estimation of OH bond dissociation energies for N-t-butylhydroxamic acids

Abstract

E.s.r. spectroscopy has been used to determine the equilibrium constants for the hydrogen exchange reactions between N-t-butylhydroxamic acids and the stable piperidine N-oxyl (1); since the O–H bond strength in (1)-H is known, this gives an estimate of the O–H bond strengths in the hydroxamic acids. These are found to be stronger than those in dialkyl nitroxide and increase with increasing electron demand in the acyl group.