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 IV (O)(TMP) ( 1 ) and Mn IV (O)(TDCPP) ( 2 ), are capable of activating the C–H bonds of hydrocarbons, including unactivated alkanes such as cyclohexane, via an oxygen non-rebound mechanism. Interestingly, 1 with an electron-rich porphyrin is more reactive than 2 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 1 and 2 is reversed, showing that 2 is more reactive than 1 . 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.