Structure and Unprecedented Reactivity of a Mononuclear Nonheme Cobalt(III) Iodosylbenzene Complex

A mononuclear nonheme cobalt(III) iodosylbenzene complex, [Co^III(TQA)(OIPh)(OH)]²⁺ (1), is synthesized and characterized structurally and spectroscopically. While 1 is a sluggish oxidant in oxidation reactions, it becomes a competent oxidant in oxygen atom transfer reactions, such as olefin epoxidation, in the presence of a small amount of proton. More interestingly, 1 shows a nucleophilic reactivity in aldehyde deformylation reaction, demonstrating that 1 has an amphoteric reactivity. Another interesting observation is that 1 can be used as an oxygen atom donor in the generation of high-valent metal-oxo complexes. To our knowledge, we present the first crystal structure of a Co^III iodosylbenzene complex and the unprecedented reactivity of metal-iodosylarene adduct.