The binding of organic peroxides to metal centers occurs naturally as well as in industrial processes. Subsequent reactions often break the O-O bond in oxidation processes that can be "heteroleptic" (creating two ions) or "homoleptic" (spliting the electrons of the bond evenly to create two radicals). DiPasquale et al. report on a Ti(IV) complex (1), Cp2Ti(OO tBu)Cl (where Cp is h5-C5H5 and tBu is tert-butyl) that reacts with triethylphosphine (PEt3) to form the phosphinite Et2PO tBu in near-quantitative yield. The authors argue for a mechanism in which the O-O bond undergoes homolysis so that the ·O tBu group reacts with PEt3 to form the product and an ethyl radical. Homolysis is supported by the finding of a positive activation entropy. The other product, Cp2Ti(O·)Cl, is unexpectedly stable and does not go on to oxidize PEt3 to Et3PO. -- PDS
J. Am. Chem. Soc. 10.1021/ja028500a (2002).
