A new functional model complex of extradiol-cleaving catechol dioxygenases: properties and reactivity of [FeII(BLPA)DBCH]BPh4

Ji H. Lim, Tac H. Park, Ho Jin Lee, Kang Bong Lee, Ho G. Jang

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Abstract

[FeII(BLPA)DBCH]BPli4 (1), a new functional model for the extradiol-cleaving catechol dioxygenases, has been synthesized, where BLPA is bis(6-methyl-2-pyridylmethyl)(2-pyridylmethyl)amine and DBCH is 3,5-di/e/7-butylcatecholate monoanion. 1H NMR and EPR studies confirm that 1 has a high-spin Fe(II) (S = 2) center. The electronic spectrum of 1 exhibits one absorption band at 386 nm, showing the yellow color of the typical [FeII(BLPA)J complex. Upon exposure to O2, 1 is converted to an intense blue species within a minute. This blue species exhibits two intense bands at 586 and 960 nm and EPR signals at g = 5.5 and 8.0 corresponding to the high-spin Fe(III) complex (S = 5/2, E/D = 0.11 ). This blue complex further reacts with O2 to be converted to (μ-oxo)FeIII2 complex within a few hours. Interestingly, 1 affords intradiol cleavage (65%) and extradiol cleavage (20%) products after the oxygénation. It can be suggested that 1 undergoes two different oxygenation pathways. The one takes the substrate activation mechanism proposed for the intradiol cleavage products after the oxidation of the FeII to FeIII. The other involves the direct attack of O2 to FeII center, forming the FeIII-superoxp intermediate which can give rise to the extradiol cleavage products. 1 is the first functional Fe(II) complex for extradiol-cleaving dioxygenases giving extradiol cleavage products.

Original languageEnglish (US)
Pages (from-to)1428-1432
Number of pages5
JournalBulletin of the Korean Chemical Society
Volume20
Issue number12
Publication statusPublished - Dec 20 1999

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ASJC Scopus subject areas

  • Chemistry(all)

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