A Nonheme Mononuclear {FeNO}<sup>7</sup> Complex that Produces N<sub>2</sub>O in the Absence of an Exogenous Reductant
Aniruddha Dey, Jesse B. Gordon, Therese Albert, Sinan Sabuncu, Maxime A. Siegler, Samantha N. MacMillan, Kyle M. Lancaster, Pierre Moënne‐Loccoz, David P. Goldberg
Abstract
Abstract A new nonheme iron(II) complex, Fe II (Me 3 TACN)((OSi Ph2 ) 2 O) ( 1 ), is reported. Reaction of 1 with NO (g) gives a stable mononitrosyl complex Fe(NO)(Me 3 TACN)((OSi Ph2 ) 2 O) ( 2 ), which was characterized by Mössbauer ( δ =0.52 mm s −1 , |Δ E Q |=0.80 mm s −1 ), EPR ( S =3/2), resonance Raman (RR) and Fe K‐edge X‐ray absorption spectroscopies. The data show that 2 is an {FeNO} 7 complex with an S =3/2 spin ground state. The RR spectrum ( λ exc =458 nm) of 2 combined with isotopic labeling ( 15 N, 18 O) reveals ν(N‐O)=1680 cm −1 , which is highly activated, and is a nearly identical match to that seen for the reactive mononitrosyl intermediate in the nonheme iron enzyme FDPnor (ν(NO)=1681 cm −1 ). Complex 2 reacts rapidly with H 2 O in THF to produce the N‐N coupled product N 2 O, providing the first example of a mononuclear nonheme iron complex that is capable of converting NO to N 2 O in the absence of an exogenous reductant.