A Nonheme Sulfur‐Ligated {FeNO}6 Complex and Comparison with Redox‐Interconvertible {FeNO}7 and {FeNO}8 Analogues

• Published in: Angewandte Chemie International Edition Vol. 57; no. 41; pp. 13465 - 13469
• Main Authors: Dey, Aniruddha, Confer, Alex M., Vilbert, Avery C., Moënne‐Loccoz, Pierre, Lancaster, Kyle M., Goldberg, David P.
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 08.10.2018
• Edition: International ed. in English
• Subjects: Ferrous Compounds - chemistry; iron; Nitric Oxide - chemistry; nitrosyl ligands; NMR; nonheme complexes; Nuclear magnetic resonance; Oxidation; Oxidation-Reduction; Photolysis; Sulfur; Sulfur - chemistry; iron; sulfur; nonheme complexes; photolysis; nitrosyl ligands
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.201806146

A nonheme {FeNO}6 complex, [Fe(NO)(N3PyS)]2+, was synthesized by reversible, one‐electron oxidation of an {FeNO}7 analogue. This complex completes the first known series of sulfur‐ligated {FeNO}6–8 complexes. All three {FeNO}6–8 complexes are readily interconverted by one‐electron oxidation/reduction. A comparison of spectroscopic data (UV/Vis, NMR, IR, Mössbauer, X‐ray absorption) provides a complete picture of the electronic and structural changes that occur upon {FeNO}6–{FeNO}8 interconversion. Dissociation of NO from the new {FeNO}6 complex is shown to be controlled by solvent, temperature, and photolysis, which is rare for a sulfur‐ligated {FeNO}6 species. NO, NO, NO! A nonheme thiolate‐ligated {FeNO}6 complex was synthesized by oxidation of its {FeNO}7 analogue to complete the first sulfur‐ligated redox‐interconvertible {FeNO}6–8 series (see picture). The series exhibits a unique change from a low‐spin to a high‐spin state upon stepwise reduction of the {FeNO}6 species to {FeNO}8. The thiolate‐ligated {FeNO}6 species showed photolability of the nitrosyl ligand without S‐oxygenation.