Nitroso compounds, spin trapping rate

Rate constants for spin trapping of alkyl radicals measured by the procedures outlined here, are collected with other spin-trapping rate data in Table 5. It will be seen that most nitrone and nitroso traps scavenge reactive radicals of diverse types with rate constants generally in the range 10s-10 1 mol-1 s l. Of the nitroso-compounds, the nitroso-aromatics (except for the very crowded TBN) are particularly reactive, whilst MBN and DMPO are the most reactive nitrones. Much of the data for spin trapping by nitrones has been accumulated by Janzen and his colleagues, who have discussed in a short review how steric and electronic factors influence these reactions (Janzen et ai, 1978). 

Spin Trapping Rate Constants with Nitroso Compounds... 

Aliphatic primary and secondary nitroso compounds are not stable but tautomerize to oximes. In nitrosocyclohexane the special steric conditions favor a dimerization rather than a tautomerization. The dimer is reduced polarographically in a six-electron reaction to A, A -dicyclohexylhydrazine [71]. Aliphatic Miitro compounds are dimers in the solid state, but dissociates in solution to a degree depending on the solvent the monomer is easier reducible than the dimer [72]. Only the monomer reacts as a spin trap the rate constant for the dissociation in MeCN is 1.5 x 10" s" [72a]. 

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