Direct Reduction of NO to N 2 O by a Mononuclear Nonheme Thiolate Ligated Iron(II) Complex via Formation of a Metastable {FeNO} 7 Complex.

Addition of NO to a nonheme dithiolate-ligated iron(II) complex, Fe II (Me 3 TACN)(S 2 SiMe 2 ) ( 1 ), results in the generation of N 2 O. Low-temperature spectroscopic studies reveal a metastable six-coordinate {FeNO} 7 intermediate ( S = 3/2) that was trapped at -135 °C and was characterized by low-temperature UV-vis, resonance Raman, EPR, Mössbauer, XAS, and DFT studies. Thermal decay of the {FeNO} 7 species leads to the evolution of N 2 O, providing a rare example of a mononuclear thiolate-ligated {FeNO} 7 that mediates NO reduction to N 2 O without the requirement of any exogenous electron or proton sources.