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Structures and Properties of Novel Mononuclear Iron(III) Complexes with Benzimidazole Containing Tripodal Tetradentate Ligands

2000; Wiley; Volume: 626; Issue: 1 Linguagem: Inglês

10.1002/(sici)1521-3749(200001)626

1521-3749

M. Pascaly, Çetin Nazikkol, F. Schweppe, A. Wiedemann, K. Zurlinden, Bernt Krebs,

CO2 Reduction Techniques and Catalysts

The iron(III) complexes of the tripodal benzimidazole-containing ligands tris(2-benzimidazolylmethyl)amine (ntb), bis(2-benzimidazolylmethyl)(2-hydroxyethyl)-amine (bbimae) and tris(5,6-dimethyl-2-benzimidazolylmethyl)amine (me2ntb) are structural and functional models for intradiol cleaving catechol dioxygenases. The complexes [Fe(ntb)Cl2]Cl · 3 CH3OH (1; P 1, a = 9.830(2) Å, b = 12.542(3) Å, c = 13.139(3) Å, α = 82.88(3)°, β = 73.45(3)°, γ = 85.53(3)°, V = 1539.2(6) Å3; Z = 2) and [Fe(bbimae)Cl2]Cl (2; P21/n, a = 7.461(2) Å, b = 18.994(5) Å, c = 14.515(4) Å, β = 98.22(2)°, V = 2035.8(9) Å3, Z = 4) have been characterized by X-ray crystallography and spectroscopic methods. In the octahedrally coordinated complexes two cis coordination sites – essential for catechol binding – are occupied by chloride ligands. The significant intradiol cleaving catechol dioxygenase activity of the model complexes was examined using 3,5-di-tert-butylcatechol as a substrate. Die Strukturen und Eigenschaften neuer mononuklearer Eisen(III)-Komplexe mit benzimidazolhaltigen vierzähnigen Tripod-Liganden Die Eisen(III)-Komplexe der benzimidazolhaltigen vierzähnigen Tripod-Liganden Tris(2-benzimidazolylmethyl)amin (ntb), Bis(2-benzimidazolylmethyl)(2-hydroxyethyl)amin (bbimae) und Tris(5,6-dimethyl-2-benzimidazolylmethyl)amin (me2ntb) sind strukturelle und funktionelle Modellverbindungen für die intradiol spaltenden Catecholdioxygenasen. Die Komplexe [Fe(ntb)Cl2]Cl · 3 CH3OH (1; P 1, a = 9.830(2) Å, b = 12.542(3) Å, c = 13.139(3) Å, α = 82.88(3)°, β = 73.45(3)°, γ = 85.53(3)°, V = 1539.2(6) Å3; Z = 2) und [Fe(bbimae)Cl2]Cl (2; P21/n, a = 7.461(2) Å, b = 18.994(5) Å, c = 14.515(4) Å, β = 98.22(2)°, V = 2035.8(9) Å3, Z = 4) wurden mit röntgenographischen und spektroskopischen Methoden charakterisiert. In den oktaedrisch koordinierten Komplexen sind zwei cis-ständige Koordinationsstellen, die essentiell für die Anbindung von Catechol sind, durch Chloroliganden besetzt. Die Komplexe der drei Liganden zeigen signifikante intradiolspaltende Catecholdioxygenase-Aktivitäten bei Verwendung von 3,5-Di-tert-butylcatechol als Substrat.