2,2,6,6 -tetramethylpiperidinyl-N-oxyl

Fig. 16 Proposed mechanism for the ruthenium/2,2, 6,6 -tetramethylpiperidinyl-.N-oxyl catalysed oxidation of alcohols...

Table 2 Ruthenium/2,2, 6,6 -tetramethylpiperidinyl-N-oxyl (TEMPO) catalysed oxidation of primary and secondary alcohols to the corresponding aldehyde using molecular oxygen. 15 mmol substrate, 30 ml chlorobenzene, RuCl2(PPh3)3/TEMPO ratio of 1/3, 10 ml min O2/N2 (8/92 v/v), P=10 bar, T=100 °C ...

Ananchenko, G. S., and Fischer, H. (2001). Decomposition of model alkoxyamines in simple and polymerizing systems. I. 2,2,6,6-tetramethylpiperidinyl-N-oxyl-based compounds. J. Polym. Sci., Part A Polym. Chem., 59(20) 3604-3621. 

NMP can be achieved in either of two ways (1) by adding a stable nitroxyl radical to the polymerization reaction initiated by traditional initiators (peroxides or azo compounds) to generate an alkoxyamine in situ, or (2) by preparing an alkoxyamine to be used as the initiator. Two widely stndied examples of stable nitroxyl radicals are 2,2,6,6-tetramethylpiperidinyl-l-oxyl [2564-83-2] (4, TEMPO) or 4-substitnted derivatives thereof and N-tert-bntyl-iV-[l-(diethylphosphono)-2,2-dimethylpropyl]nitroxide [188526-94-5] (5) (165-172). 

Kim and Jung (2003) oxidized benzylic and allylic alcohols by molecular oxygen in presence of catalytic amounts of 2,2,6,6-tetramethylpiperidinyl-l-oxyl (TEMPO) and CAN (scheme 64). Molecular oxygen is reduced to water by oxidation of Ce + to Ce . The nitroxyl radical of TEMPO is oxidized to the A-oxoammonium cation by Ce +. The N-oxoammonium cation then oxidizes the alcohol to a carbonyl compound. The reactions were carried out in refluxing acetonitrile and molecular oxygen was bubbled through the reaction mixture. The amount of CAN varied between 10 and 20 mol%, and the amount of TEMPO... 

Spin probes at the fast motional limit have also been utilized in studies of heterogeneous molecular assembly by HF EPR. Cramer et al. utilized the spin probe TEMPO (2,2,6,6-tetramethylpiperedine-l-oxyl) to investigate poly(butylacrylate) and poly(butylmethacrylate) films. The same spin probe was also used by Smirnov and co-workers to study rotational diffusion of the nitroxide in two phases of aqueous phospholipid dispersions with W-band EPR. Bakker and co-workers utilized another probe - 4-[N,N-dimethyl-lV-(n-hexadecyl)ammonium]-2,2,6,6-tetramethylpiperidinyl-iV-oxyl (HTAB ) to study absorption and aggregation of cetylpyridinium chloride and cetylpyridin-ium salicylate (CPSa) on silica nanoparticles. From W-band line width analysis it was concluded that CPSa on silica surfaces forms two coexisting aggregate phases, one which excludes HTAB and one in which HTAB is concentrated. 

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