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

Abstract

A mononuclear nonheme cobalt(III) iodosylbenzene complex, [CoIII(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 CoIII iodosylbenzene complex and the unprecedented reactivity of metal‐iodosylarene adduct.

The Oxo-Wall Remains Intact: A Tetrahedrally Distorted Co(IV)–Oxo Complex

“…Although data were recorded to 16 Å −1 , the data were analyzed only to 14.5 Å −1 owing to noise at high k. Data were subsequently processed and analyzed as previously reported using EXAFS123 and FEFF 9.4. 78 Errors to the models are reported as ε 2 values.…”

Hydride-Transfer Reaction to a Mononuclear Manganese(III) Iodosylarene Complex

“…3,4 Further, a recent study by Nam and coworkers reported the amphoteric reactivity of a cobalt(III) iodosylbenzene complex. 5 Nevertheless, various chemical properties and reaction mechanisms of metal iodosylarene species still remain unexplored.…”

“…For decades, it has been actively debated whether a metal iodosylarene adduct, a precursor of the corresponding high-valent metal oxo species, acts directly as a reactive oxidant in the reactions involving a metal catalyst and an iodosylarene via a multiple-oxidant mechanism . To understand the nature of the metal iodosylarene species, several model complexes bearing an iodosylarene unit have been prepared and then characterized with various physicochemical methods including X-ray crystallography. − …”

“…Comprehensive reactivity studies have been performed experimentally and show that the metal iodosylarene species truly exerts electrophilic oxidative reactions with organic compounds in aliphatic C–H bond activation, sulfoxidation, epoxidation, etc. , Further, a recent study by Nam and co-workers reported the amphoteric reactivity of a cobalt­(III) iodosylbenzene complex . Nevertheless, various chemical properties and reaction mechanisms of metal iodosylarene species still remain unexplored.…”

A mononuclear nonheme manganese(III)‐acylperoxo complex: Synthesis, characterization, and reactivity studies

“…Of importance here, is the fact that multiple‐oxidant mechanism, which consists of the involvement of multiple and distinct active metal‐oxygen species as well as metal‐oxidant adducts, has recently brought an unknown territory that needed to be explored, especially, new mechanistic pathways and reexamination of the nature of the actual active oxidants 17–21 …”