Radical pair definition

Not surprisingly, bifunctional species preceded the definition of the term distonic, both in the gas and condensed phases. For example, Hammond et al. studied the cage effect for radical pairs generated by decomposition of azo compounds. Among their targets was the doubly protonated amidine (27), whose decomposition yielded a pair of distonic radical cations (28 +).Attachment of the spin-bearing carbon in the 2-position of the diazaallyl function ensures minimal delocalization of unpaired spin into the latter. 

In addition to not addressing the need for individual tumbling rate constants for radical pair combinations leading to 3b, 2-BN, and 4-BN, Scheme 13.5 does not take into account the fact the values of probably differ and the translational rate constants definitely differ within amorphous and interfacial cages of either LDPE or HDPE. 

Deetarbonybaion (2, 4SI 3, 327 329). The definitive paper by Walborsky and Allen on the stereochemistry of the reaction has now been published. These chemists conclude that the reaction involves a radical pair ... 

Generation of a radical pair or biradical in a definite electron spin state. This has already been expounded on in Section II.A, item 1. 

Chemically mduced dynamic nuclear polarization (cidnp) arises in some radical pair processes and is characterized by intensity inversion and enhancement of some of the resonances in the nmr spectra of radical combination products during a reaction.This provides definitive evidence for the involvement of radicals, but as with ESR, it is difficult to quantitatively estimate the fraction of the total reaction proceeding via the radical path. The conditions under which a cidnp effect will be observed are rather limited, and it has only been observed in a few cases with organometallics. In particular, situations in which a metal-based radical can be implicated are extremely rare. Nevertheless, with quantitative... 

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