Kinetics and mechanism of the stoichiometric oxygenation of [CuII(fla)(idpa)]ClO4 [fla = flavonolate, idpa = 3,3′-imino-bis(N,N-dimethylpropylamine)] and the [CuII(fla)(idpa)]ClO4-catalysed oxygenation of flavonol

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Abstract

Oxygenation of [CuII(fla)(idpa)]ClO4 (fla = flavonolate; idpa = 3,3′-iminobis(N,N-dimethylpropylamine)) in dimethylformamide gives [CuII(idpa)(O-bs)]ClO4 (O-bs = O-benzoylsalicylate) and CO. The oxygenolysis of [CuII(fla)(idpa)]ClO4 in DMF was followed by electronic spectroscopy and the rate law -d[{CuII(fla)(idpa)}ClO4]/dt = kobs[{CuII(fla)(idpa)}ClO4][O2] was obtained. The rate constant, activation enthalpy and entropy at 373 K are kobs = 6.13 ± 0.16 × 10-3 M-1s-1, ΔH = 64 ± 5 kJ mol-1, ΔS = -120 ± 13 J mol-1 K-1, respectively. The reaction fits a Hammett linear free energy relationship and a higher electron density on copper gives faster oxygenation rates. The complex [CuII(fla)(idpa)]ClO4 has also been found to be a selective catalyst for the oxygenation of flavonol to the corresponding O-benzoylsalicylic acid and CO. The kinetics of the oxygenolysis in DMF was followed by electronic spectroscopy and the following rate law was obtained: -d[flaH]/dt = kobs[{CuII(fla)(idpa)}ClO4][O2]. The rate constant, activation enthalpy and entropy at 403 K are kobs = 4.22 ± 0.15 × 10-2 M-1s-1, ΔH = 71 ± 6 kJ mol-1, ΔS = -97 ± 15 J mol-1 K-1, respectively.

Original languageEnglish
Pages (from-to)83-91
Number of pages9
JournalInorganica Chimica Acta
Volume320
Issue number1-2
DOIs
Publication statusPublished - Aug 13 2001

Keywords

  • Copper complexes
  • Dioxygenation
  • Flavonolate complexes
  • Kinetics and mechanism

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry
  • Materials Chemistry

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