Synthesis of Fe<sup>III</sup> and Fe<sup>IV</sup> Cyanide Complexes Using Hypervalent Iodine Reagents as Cyano‐Transfer One‐Electron Oxidants
Charafa Souilah, Sergio A. V. Jannuzzi, Derya Demirbaş, Sergei I. Ivlev, Marcel Swart, Serena DeBeer, Alicia Casitas
Abstract
Abstract We disclose a new reactivity mode for electrophilic cyano λ 3 ‐iodanes as group transfer one‐electron oxidants to synthesize Fe III and Fe IV cyanide complexes. The inherent thermal instability of high‐valent Fe IV compounds without π‐donor ligands (such as oxido (O 2− ), imido (RN 2− ) or nitrido (N 3− )) makes their isolation and structural characterization a very challenging task. We report the synthesis of an Fe IV cyanide complex [(N 3 N′)FeCN] ( 4 ) by two consecutive single electron transfer (SET) processes from Fe II precursor [(N 3 N′)FeLi(THF)] ( 1 ) with cyanobenziodoxolone (CBX). The Fe IV complex can also be prepared by reaction of [(N 3 N′)Fe III ] ( 3 ) with CBX. In contrast, the oxidation of Fe II with 1‐cyano‐3,3‐dimethyl‐3‐(1H)‐1,2‐benziodoxole (CDBX) enables the preparation of Fe III cyanide complex [(N 3 N′)Fe III (CN)(Li)(THF) 3 ] ( 2‐Li THF ). Complexes 4 and 2‐Li THF have been structurally characterized by single crystal X‐ray diffraction and their electronic structure has been examined by Mössbauer, EPR spectroscopy, and computational analyses.