A Room‐Temperature Stable Distonic Radical Cation

Abstract

AbstractDistonic radical cations (DRCs) with spatially separated charge and radical sites have, so far, largely been observed by gas‐phase mass spectrometry and/or matrix isolation spectroscopy work. Herein, we disclose the isolation of a crystalline dicarbondiphosphide‐based β‐distonic radical cation salt 3.+(BARF) (BARF=[B(3,5‐(CF3)2C6H3)4)]−) stable at room temperature and formed by a one‐electron‐oxidation‐induced intramolecular skeletal rearrangement reaction. Such a species has been validated by electron paramagnetic resonance (EPR) spectroscopy, single‐crystal X‐ray diffraction, UV/Vis spectroscopy and density functional theory (DFT) calculations. Compound 3.+(BARF) exhibits a large majority of spin density at a two‐coordinate phosphorus atom (0.74 a.u.) and a cationic charge located predominantly at the four‐coordinate phosphorus atom (1.53 a.u.), which are separated by one carbon atom. This species represents an isolable entity of a phosphorus radical cation that is the closest to a genuine phosphorus DRC to date.