CONFORMATIONALLY PROTECTED HYDRAZINE RADICAL CATIONS AND THE GEARING EFFECT ON A HYDRAZINE ELECTRON-TRANSFER REACTION

The N-isopropylated hydrazine radical cations from 7 (22/tBu,iPr) and 9 (22/iPr2) are isolable and are the first examples of isolable hydraz ine radical cations which lack all C(alpha)-H bonds being protected as bridgehead carbons in bicyclic rings. The cyclic voltammogram of 9 sh ows electrochemically irreversible oxidation and reduction waves at pl atinum. It is argued that this results from a gearing effect of the is opropyl groups, which causes the radical cation from neutral 9 to be g enerated in an unstable conformation. Kinetic and thermodynamic confor mational effects which cause hydrazine cyclic voltammetry curves to be electrochemically irreversible are contrasted.