One-Electron Oxidation of an Organic Molecule by B(C₆F₅)₃; Isolation and Structures of Stable Non-<i>para</i>-substituted Triarylamine Cation Radical and Bis(triarylamine) Dication Diradicaloid

Abstract

The methylene-bridged triphenylamine 2 has been oxidized to planar radical cation 2(•+) by B(C6F5)3 or Ag(+). Further reaction of 2(•+)[Al(ORF)4](-) and 2 with trace amounts of silver salt resulted in dication 3(2+), providing a rare example of structurally characterized bis(triarylamine) "bipolarons". 3(2+) can be directly prepared by the reaction of 3 with 2 equiv of Ag(+). X-ray structural analysis together with theoretical calculation shows that 3(2+) has singlet diradical character and is analogous to Chichibabin's hydrocarbons.