The reaction of [(η5-cyclohexadienyl)Fe(CO)3]+BF4− with 2-methyl-2-nitrosopropane: an unexpected oscillating reaction

The reaction of 2-methyl-2-nitrosopropane with the organometallic cation [(η5-cyclohexadienyl)tricarbonyliron]+ yields the bis(t-butyl)nitroxide radical which is detected by ESR spectroscopy. The intensity of the ESR signal varies in an oscillatory manner with time and the ESR silent period between oscillations ranges from 15 minutes to one hour, depending on the relative concentrations of the reagents. Some years ago, Turcsanyi proposed (Acta Chim., Acad. Scient. Hungar., 110 (1982) 305, Chem. Abs. 97 188877w) that a RNO/RNHOH system might exhibit oscillatory behaviour and the data presented are an experimental realization of that prediction. A mechanistic rationale is proposed to account for the observations.