Study of the catalytic mechanism of a non-heme Fe catalyst: The role of the spin state of the iron

The oxidative catalytic evolution of a highly efficient non-heme Fe catalyst (LFeIII) was studied using EPR and Low-Temperature UV-Vis spectroscopies. The key transient-intermediates of the Fe center were monitored during the catalytic cycle, in the presence of H2O2. The EPR data show that this non-heme Fe catalyst can evolve via either High-Spin or Low-Spin states of the Fe center, with only the Low-Spin path being catalytically efficient. The key transient, intermediate [LFeIII-OOH] in the Low-Spin path has also been monitored with Low-Temperature UV-Vis. Arrhenius analysis allowed determination of the energy barrier E-a = 18.5 +/- 6.2 kJ/mole for the Low-Spin path.

Automated summary

The study investigated the oxidative catalytic evolution of a highly efficient non-heme Fe catalyst using EPR and Low-Temperature UV-Vis spectroscopies. It was found that the Fe center can evolve via High-Spin or Low-Spin states, with only the Low-Spin path being catalytically efficient. Arrhenius analysis determined an energy barrier of E-a = 18.5 +/- 6.2 kJ/mol for the Low-Spin path.