Tuning the Reactivity of TEMPO by Coordination to a Lewis Acid: Isolation and Reactivity of MCl3(η1-TEMPO) (M = Fe, Al)

Addition of 2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO) to MCl3 (M = Fe, Al). results in the formation of MCl3(eta(1)-TEMPO). [M = Fe (1), Al (2)] Both 1 and 2:oxidize alcohols to. generate ketones or aldehydes 'along' with the reduced complexes MCl3(eta(1)-TEMPOH) [M = Fe (3), Al (4)]. Complexes 1-4 were fully characterized including analysis by X-ray crystallography. Additionally, control experiments indicated that neither MCl3 (M = Al, Fe)nor, TEMPO are capable of effecting the Oxidation:of alcohols independently.