Abstract
A new alkylthiolate-ligated nonheme iron complex, Fe(II)(BNPA(Me2)S)Br (1), is reported. Reaction of 1 with O(2) at -40 °C, or reaction of the ferric form with O(2)(•-) at -80 °C, gives a rare iron(III)-superoxide intermediate, [Fe(III)(O(2))(BNPA(Me2)S)](+) (2), characterized by UV-vis, (57)Fe Mössbauer, ATR-FTIR, EPR, and CSIMS. Metastable 2 then converts to an S-oxygenated Fe(II)(sulfinate) product via a sequential O atom transfer mechanism involving an iron-sulfenate intermediate. These results provide evidence for the feasibility of proposed intermediates in thiol dioxygenases.