A Two-State Reactivity Model Explains Unusual Kinetic Isotope Effect Patterns in CH Bond Cleavage by Nonheme Oxoiron(IV) Complexes

✍ Scribed by Eric J. Klinker; Sason Shaik; Hajime Hirao; Lawrence Que Jr.

• Publisher: John Wiley and Sons
• Year: 2009
• Tongue: English
• Weight: 315 KB
• Volume: 48
• Category: Article
• ISSN: 0044-8249
• DOI: 10.1002/anie.200804029

✦ Synopsis

Abstract

It's in the bond: The cleavage of CH bonds by two related oxoiron(IV) complexes shows a range of kinetic isotope effect (KIE) values that exhibit an unusual dependence on the CH bond strength. Large nonclassical KIEs are observed for bond strengths below 93 kcal mol^−1^, while semiclassical values are found above this value (see graph, DHA=9,10‐dihydroanthracene). This nonintuitive behavior can be rationalized by invoking a two‐state reactivity model.magnified image