Rapid Communication Spin-Driven Activation of Dioxygen in Various Metalloenzymes and Their Inspired Models

Abstract: Although potentially powerful, molecular oxygen is an inert oxidant due to the triplet nature of its ground state. Therefore, many enzymesse various metal cations (M) to produce singlet active species MnO2. In this communication we investigate the topology of the Electron Localization Function (ELF) within five biomimetic complexes which are representative of the strategies followed by metalloenzymes to activate O2. Thanks to its cou-pling to the constrained DFT methods the ELF analysis reveals the tight connection between the spin state of the adduct and the spatial organization of the oxygen lone pairs. We suggest that enzymes could resort to spin state control to tune the regioselectivity of substrate oxidations. q 2010 Wiley Periodicals, Inc. J Comput Chem 00: 000–000, 2010 Key words: enzyme; spin; electron localization; DFT; constrained DFT The need for green, profitable, and highly selective catalytic processes is becoming increasingly acute. When targeting oxy-genation and/or oxidation of saturated compounds, one appealing route is to use molecular oxygen, a readily available chemical, as the oxidant. In its ground state the free dioxygen molecule is however a spin-polarized triplet and as such is inert toward sub