Heterocyclic free radicals. Part 1. 4,5-Diazafluorene derivatives of Koelsch’s free radical: an EPR and metal-ion complexation study †

• DOI: 10.1039/a909109b
• Publication Date: 2002-07-26T09:06:44Z
• Authors: M. John Plater; Steven Kemp; Eric Lattmann
• Keywords: Potassium permanganate; Radical ion

Heteroaromatic precursors to nitrogen substituted derivatives of Koelsch's free radical have been prepared by the condensation 4,5-diazafluorene with a fluorenylidene or diazafluorenylidene. These compounds appear coloured and can exist in different tautomeric forms. An improved one pot synthesis 4,5-diazafluorenone has developed oxidative ring contraction 1,10-phenanthroline aqueous potassium permanganate. Aza are easily generated oxidation appropriate K3Fe(CN)6. Treatment 9-[(9H-4,5-diazafluoren-9-ylidene)phenylmethyl]-9H-fluoren-9-yl CuCl2 EtOH gives brown precipitate 1∶1 radical–ligand complex.