Synthesis and EPR/UV/Vis‐NIR Spectroelectrochemical Investigation of a Persistent Phosphanyl Radical Dication

Abstract

AbstractThe reaction of the bis(imidazoliumyl)‐substituted PI cation [(2‐ImDipp)P(4‐ImDipp)]+ (10+) (2‐Im=imidazolium‐2‐yl; 4‐Im=imidazolium‐4‐yl; Dipp=2,6‐di‐isopropylphenyl) with trifluoromethanesulfonic acid (HOTf) or methyl trifluoromethylsulfonate (MeOTf) yields the corresponding protonated [(2‐ImDipp)PH(4‐ImDipp)]2+ (112+) and methylated [(2‐ImDipp)PMe(4‐ImDipp)]2+ (122+) dications, respectively. EPR/UV/Vis‐NIR spectroelectrochemical investigation of the low‐coordinated PI cation 10+ predicted a stable and “bottleable” P‐centered radical dication [(2‐ImDipp)P(4‐ImDipp)]2+. (132+.). The reaction of 10+ with the nitrosyl salt NO[OTf] yields the persistent phosphanyl radical dication 132+. as triflate salt in crystalline form. Quantum chemical investigation revealed an exceptional high spin density at the P atom.