Relaxation methods kinetic isotope effect

Mu-substituted hexadienyl radicals are easily observed by high-field tS Rotation and their reaction with benzoquinone has been studied. The method is principally the same as in the Mu relaxation kinetics but, since Mu-substituted tmlicals are measured, the disappearance rate of MuO H is determined from the line broadening of the Fourier transformation power spectrum. The obtained value is kjj = 2.8 x 10 M- s- . It is important to note tlmt the reaction rate constant of Mu-substituted radicals may not differ much from that of the H-counterparts. The isotope effect should be small since the mass of Mu- and H-radicals are not much different, and since the reaction center is arated from the site of Mu- and H-addition. 

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