Turning on the triplet state channel in the excess electron scavenging by nitroxyl radicals in liquid alkanes

It has been found that the effective radius of the reaction of excess electrons capture by 4-phenyl-2,2,3,5,5-pentamethyl-imidazolidin-1-oxyl in n-dodecane, n-decane, and n-hexane increases steeply by a factor of about four, reaching values typical for molecular acceptors, when the temperature is reduced below 290, 280, and 250, respectively. A kinetic model of the capture that is based on the assumption of equilibrium between electron detachment and intersystem crossing in the triplet state of the diradical anion is suggested and briefly discussed.

53Highlights► Scavenging of solvated electrons by nitroxyl radicals proceeds via spin-dependent pathways. ► The scavenging via the triplet state is promoted by the electron-accepting group in the radicals. ► In alkanes, the electron capture via triplet state of the diradical anion may depend strongly on temperature.