REDOX-INITIATED RADICAL DECOMPOSITION OF TRIAZENES AND THEIR PLATINUMCOMPLEXES STUDIED BY CYCLIC VOLTAMMETRY AND EPR SPECTROSCOPY

Triazenes p-R(1)-C6H4-N=N-NR(2)R(3) (R(1) = H, butyl, CH3O, CN and NO2 , R(2) = CH3, cyclohexyl, butyl or longer chains, R(3) = H, OH) are ir reversibly cathodically reduced at -1.5 to -2.7 V (vs, saturated calom el electrode) and oxidised from 0.8 to 1.7 V. The reduction peak poten tials became more negative and the first oxidation peak potentials les s positive if R(3) was OH. Using spin-trapping, radicals p-R(1)C(6)H(4 )(.) and (.)R(2) were identified as fragmentation products in the elec trolytic and peroxy-initiated decomposition of triazenes. Radicals p-R (1)C(6)H(4)-NO.-R(2), representing the oxidised cage products after N- 2 elimination, were observed in the oxidation of triazenes with peroxy acid. An NO2-centred radical anion was found in the cathodic reductio n of a Pt complex with R(1) = NO2. The above specified decomposition r oute of triazenes is modified if these are coordinated in Pt complexes . The formation of radicals is discussed assuming two tautomeric forms of triazenes.