CIDNP During Aroyl Peroxide Decompositions

Pr denotes the product of the induced decomposition, which may be 0-COj—R, where R is the radical derived from the solvent (RH). The yields of the cage products phenylbenzoate and diphenyl amount to 4% and 0.1 %, respectively. 

The benzene or substituted benzene emissions may change to enhanced absorptions and the phenylbenzoate absorptions may change to emissions if dibenzoyl peroxides are irradiated in solutions containing such added effective triplet sensitizers, as Michler s ketone, 2-acetonaphthone, 1 -acetonaphthone, acetophenone, benzophenone, acetone and cyclohexanone An example 

The changes of polarizations with the addition of various sensitizers may be regarded as strong evidence for the radical pair mechanisms of CIDNP and provide a nice example of the dependence of the effects on the precursor states. Two other important features of CIDNP also become apparent from the results of the studies outlined above. 

The first ist the strong dependence of observed CIDNP intensities on the nuclear spin lattice relaxation times Ti of the products. As is seen from Eqs. 

---