2.2.6.6- Tetramethylpiperidine: Piperidine, 2,2,6,6-tetramethyl

The u.v.-visible spectrum of the 4-hydroxy-2,2,6,6-tetramethyl-piperidine-N-oxyl-methyl-cobinamide is very similar to methyl-cobin-amide itself and as a result this technique cannot be used to rigorously identify the spin labeled derivative. The spin labeled compound does show a spectral change with pH between pH 7.0 and pH 2.0 which methyl-cobinamide does not exhibit. Despite the similarities between methyl-cobinamide and nitroxylmethylcobinamide, the circular dichroism spectrum of the two derivatives are quite different. Fig. 23 shows the marked difference in C. D. spectra of 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl, methylcobinamide, and a methylcobinamide solution containing an equimolar amount of uncoordinated nitroxide. 

It is known that the nitrosonium cation is a strong oxidant (54). In (55) it was found by multinuclear NMR ( H, 13C, 19F and 14N) that the interaction of nitrosonium tetrafluoroborate with 2,2,6,6-tetramethyl-4-R-piperidine-1 -oxyl radicals 22a-e resulted in formation of 4-R-2,2,6,6-tetramethylpiperidine-l-oxoammonium tetrafluoroborates (Scheme 16). Cations 23a-e could be classified as nitrosonium complexes of biradicals 24a-e. 

Hydroxyethyl)-4-hydroxy-2,2,6,6-tetramethylpiperidine. See 4-Hydroxy-2,2,6,6-tetramethyl-1-piperidine ethanol (1-Hydroxyethylidene) bisphosphonic acid. See Etidronic acid... 

CAS 2403-88-5 EINECS/ELINCS 219-291-2 Synonyms 4-Hydroxy-2,2,6,6-tetramethylpiperidine 2,2,6,6-Tetramethyl-piperidin-4-ol... 

Figure 45.3 Synthesis of paullone ligands with different location of their binding sites. TEMPO = (2,2,6,6-tetramethylpiperidine-l-yl)-oxyl. TMP, 2,2,6,6-tetramethyl-piperidine.

Other hindered amines used with good results in the stabilization promotion of polyolefin, pol3mrethanes, polystyrene, ABS, acrylonitrile st)Tene copolymers, are derivatives of piperidine such as 2,2,6,6-tetramethylpiperidine, 2,2,6,6-tetramethyl-4-hydroxy-phosphonopiperineor by stable free radicals such as 4-[cyan (phenylmethylene)-2,2,6,6-tetramethyl piperidinoxil], 4-(ureidoimino)-2,2,6,6,-tetramethyl-piperidinoxil, 2, 2, 6, 6 tetramethylspiro(benzimidazoline)-2,4-piperi dinoxil. 

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