title: Cu(II)-mediated generation of triarylamine radical cations and their dimerization. an easy route to tetraarylbenzidines.
abstract: Triphenylamine (TPA) derivatives react with Cu2+ in acetonitrile to give TPA radical cations which undergo dimerization and deprotonation reactions to yield tetraphenylbenzidines (TPB). Synthetic utility of this reaction is demonstrated using several triphenylamine derivatives, and yields in excess of 80% are obtained in most cases. Involvement of the amine radical cations in these reactions was confirmed by ESR and absorption spectroscopic studies. A mechanism consistent with all observations is proposed. This study also revealed a very good correlation between the free energy change for radical cation formation and product yields.
authors: Photosciences and Photonics, Chemical Sciences and Technology Division, National Institute for Interdisciplinary Science and Technology, Trivandrum 695 019, India.
authors: Kesavapillai
authors: K
authors: Sreenath
authors: Chettiyam Veettil
authors: CV
authors: Suneesh
authors: Venugopal K Ratheesh
authors: VK
authors: Kumar
authors: Karical R
authors: KR
authors: Gopidas