A Dinitrosyliron Complex within the Homoleptic Fe(NO)₄ Anion: NO as Nitroxyl and Nitrosyl Ligands within a Single Structure

Nitrosylation of the chelate–thiolate-containing dinitrosyliron complex (DNIC) [(S­(CH₂)₃S)­Fe­(NO)₂]⁻ triggers nitric oxide (NO) activation to generate the homoleptic nitrosyl {Fe­(NO)₂}⁹ DNIC [Fe­(NO)₄]⁻ (<b>1</b>) made up of two nitroxyls (or two NO anions) attached to a delocalized {Fe­(NO)₂}⁹ motif. The significantly longer N3–O3/N4–O4 [1.380(12) and 1.280(12) Å] and Fe1–N3/Fe1–N4 [2.008(11) and 2.045(10) Ǻ] bond distances reflect that N3–O3 and N4–O4 of complex <b>1</b> may act as the nitroxyl-coordinated ligands. That is, the electronic structure of the DNIC <b>1</b> is best described as a {Fe­(NO)₂}⁹ motif coordinated by two nitroxyl (NO^–) ligands