Generation and detection of the cyclohexadienyl radical in phosphonium ionic liquids

The formation of the cyclohexadienyl radical, C(6)H(6)Mu, in ionic and molecular solvents has been compared. This is the first time that a muoniated free radical is reported in an ionic liquid. In marked contrast to molecular liquids, free radical generation in ionic liquids is significantly enhanced. Comparison of the hyper-fine interactions in the ionic liquid and in molecular solvents and with theoretical calculations, suggests significant and unforeseen solvent interaction with the cyclohexadienyl radical.