Heterocyclic free radicals. Part 1. 4,5-Diazafluorene derivatives of Koelsch's free radical

An EPR and metal-ion complexation study

M. John Plater*, Steven Kemp, Eric Lattmann

*Corresponding author for this work

Research output: Contribution to journalArticle

71 Citations (Scopus)

Abstract

Heteroaromatic precursors to nitrogen substituted derivatives of Koelsch's free radical 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.

Original languageEnglish
Pages (from-to)971-979
Number of pages9
JournalJournal of the Chemical Society, Perkin Transactions 1
Issue number6
DOIs
Publication statusPublished - 2000

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Complexation
Free Radicals
Metal ions
Paramagnetic resonance
Potassium Permanganate
Derivatives
Precipitates
Condensation
Nitrogen
Ligands
Oxidation
4,5-diazafluorenone
potassium ferricyanide
cupric chloride
1,10-phenanthroline

Keywords

  • RUTHENIUM(II) COMPLEXES
  • BRIDGING LIGANDS
  • PATHWAYS
  • DIMERS

ASJC Scopus subject areas

  • Chemistry(all)

Cite this

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abstract = "Heteroaromatic precursors to nitrogen substituted derivatives of Koelsch's free radical 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.",
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T1 - Heterocyclic free radicals. Part 1. 4,5-Diazafluorene derivatives of Koelsch's free radical

T2 - An EPR and metal-ion complexation study

AU - Plater, M. John

AU - Kemp, Steven

AU - Lattmann, Eric

PY - 2000

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N2 - Heteroaromatic precursors to nitrogen substituted derivatives of Koelsch's free radical 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.

AB - Heteroaromatic precursors to nitrogen substituted derivatives of Koelsch's free radical 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.

KW - RUTHENIUM(II) COMPLEXES

KW - BRIDGING LIGANDS

KW - PATHWAYS

KW - DIMERS

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