Halogen complexes model compounds

Noncomplementary redox reactions between halogen and oxyhalogen species often exhibit complex kinetic patterns which can be understood in terms of multistep kinetic models. The corresponding mechanisms are centered on the formation and subsequent reactions of reactive intermediates such as XO2 (X = halogen) and related compounds. Stopped-flow techniques can be used to provide insights into the redox reactions. Several examples of redox reaction are also described in Section 3.5. 

The metal-halogen exchange reaction must be carried out at low temperatures ( — 50°C), and the lithiated polymer can then be allowed to react with ClPPhj, ClSnPhj, ClAuPPhj or CO 2. The triarylphosphine groups then function as coordination sites for a variety of transition-metal systems. It should be noted that complex reaction sequences of this type require prior model compound studies with the analogous cyclic oligomers . 

Copper compounds have many uses in organic chemistry for oxidations, coupling reactions, halogenations, etc.38 (cf. also page 910). Some of these, such as the oxidation of phenols by copper-amine complexes,39 provide models for phenol-oxidizing enzymes. 

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