Tracing the Iron Nitrosyl Complex [Fe(2,2′‐bipyridine)(CN)₃(NO)]^–

Abstract

The previously reported complex [Ph 4 P][Fe(bpy)(CN) 3 (NO)] (bpy = 2,2Ј-bipyridine) was synthesised and characterised in detail using UV/Vis absorption and IR spectroscopy, cyclic voltammetry, and single-crystal XRD. Detailed spectroelectrochemical (UV/Vis, IR and EPR) insight adds perfectly to the previous electrochemical characterisation of this complex. The description of this {Fe(NO)} 7 complex as a low-spin Fe II -NO · system based on the spectroscopic results is sup-1033 ported by DFT calculations. Reversible oxidation leads to the corresponding {Fe(NO)} 6 (Fe II -NO + ) complex, whereas the reduction to the formal {Fe(NO)} 8 species [presumably (Fe II -NO -)] occurs irreversibly. When trying to synthesise further derivatives that contain other α-diimine ligands, only for the 1,10-phenanthroline (phen) derivative were some results obtained. For other ligands the obtained materials were too reactive. The reasons for such behaviour are also discussed.