Highly Reactive Manganese(IV)-Oxo Porphyrins Showing Temperature-Dependent Reversed Electronic Effect in C-H Bond Activation Reactions.

We report that Mn(IV)-oxo porphyrin complexes, Mn(O)(TMP) () and Mn(O)(TDCPP) (), are capable of activating the C-H bonds of hydrocarbons, including unactivated alkanes such as cyclohexane, via an oxygen non-rebound mechanism. Interestingly, with an electron-rich porphyrin is more reactive than with an electron-deficient porphyrin at a high temperature (e.g., 0 °C). However, at a low temperature (e.g., -40 °C), the reactivity of and is reversed, showing that is more reactive than . To the best of our knowledge, the present study reports the first example of highly reactive Mn(IV)-oxo porphyrins and their temperature-dependent reactivity in C-H bond activation reactions.