14750-07-3Relevant academic research and scientific papers
Heterocyclic free radicals. Part 1. 4,5-Diazafluorene derivatives of Koelsch's free radical: an EPR and metal-ion complexation study
Plater, M. John,Kemp, Steven,Lattmann, Eric
, p. 971 - 980 (2007/10/03)
Heteroaromatic precursors to nitrogen substituted derivatives of Koelsch's free radicals have been prepared by the condensation of 4,5-diazafluorene with a fluorenylidene or diazafluorenylidene. These compounds appear coloured and can exist in different tautomeric forms. An improved one pot synthesis of 4,5-diazafluorenone has been developed by the oxidative ring contraction of 1,10-phenanthroline with aqueous potassium permanganate. Aza derivatives of Koelsch's free radical are easily generated by oxidation of the appropriate precursors with K3Fe(CN)6. Treatment of 9-[(9H-4,5-diazafluoren-9-ylidene)phenylmethyl]-9H-fluoren-9-yl radical with CuCl2 in EtOH gives a brown precipitate of a 1:1 radical-ligand complex.
Characterization of the Excited-State Reactivity of a Persistent Aryl-Substituted Allyl Free Radical
Breslin, David T.,Fox, Marye Anne
, p. 13341 - 13347 (2007/10/02)
A family of stable aryl-substituted allyl radicals 1 (9H-fluoren-9-yl-9--9-ylidenephenylmethyls) has been characterized by electronic absorption spectroscopy, semiempirical (AM1) molecular orbital calculations, and cyclic voltammetry.Photolysis of 1a in aerated solvents that are poorer hydrogen atom sources than toluene resulted in oxygenation (ΦOX ca. 5 * 10-4) and cleavage products.A thermally reversible photocyclization mechanism is proposed to explain the oxygenation of 1a in inert solvents.Enhanced excited-state reactivity toward hydrogen and halogen atom donors was observed during the steady-state photolysis of 1a.Electron transfer from naphthalene to an excited state of 1a produces an extremely short lived (30 ps) 1a anion/naphthalene radical cation geminate pair.
