Alkyl peroxyl radicals traps

Another example of highly effective melt stabilizers are the thiolate metal complexes (e.g. MDRC, MDRP, MRX, M = Ni, Zn) which are also thermal and UV stabilizers for polyalkenes (see Section 19.3.3.1.V, 19.4.2.2.i and 19.4.2.2.ii) and no hydroperoxides can be detected in polymers containing them after processing. In addition to their peroxidolytic function dithiolates have the ability to trap alkyl peroxyl radicals The contribution of this trapping mechanism to... 

Another surprise was that interstrand cross-Unks were also formed independently of O2. However, this was initially rationalized by demonstrating that O2 reacted reversibly with 102 (Scheme 43). Nonlinear regression analysis of the ratio of thymidine to oxygenated products (eg 107) as a function of GSH concentration provided an estimated rate constant for GSH trapping of 102 (fecsH = 6.9 X 10 M s ) consistent with expectations for reaction of an alkyl radical with the thiol.The accuracy of the thiol trapping rate constant validated the extracted rate constant for O2 loss from 106 to reform 102 (feo2 = d.4 s ), which is consistent with rate constants reported for O2 loss from other peroxyl radicals. 

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