Catecholase activity of a structurally characterized dinuclear iron(III) complex [FeIII2(L)2] [H3L=N,N′-bis(3-methoxysalicylaldimine)-1,3-diaminopropan-2-ol]

• Published in: Polyhedron 2014, Vol.67, p.19-26
• Main Authors: Mitra, Merry, Maji, Ashis Kumar, Ghosh, Barindra Kumar, Raghavaiah, Pallepogu, Ribas, Joan, Ghosh, Rajarshi
• Format: Article
• Language: English
• Subjects: Biocatalytic activity; Crystal structure; Iron(III); Magnetism; Schiff base
• ISSN: 0277-5387
• DOI: 10.1016/j.poly.2013.08.064

A dinuclear Fe(III) complex, [FeIII2(L)2] (1) [H3L = N,N′-bis(3-methoxysalicylaldimine)-1,3-diaminopropan-2-ol], has been synthesized and characterized using microanalysis, spectroscopy and X-ray crystallography. Structural analysis reveals a pentadentate chelation behaviour of the trianionic ligand H3L, having a distorted octahedral coordination environment around each iron(III) center with an FeN2O4 chromophore. Variable-temperature magnetic susceptibility measurements of 1 indicate an antiferromagnetic interaction between the two iron(III) centers, coupled with J=−28.5. 1 behaves as an effective catalyst towards the oxidation of 3,5-di-tert-butylcatechol in different solvents, viz. methanol, dichloromethane and acetonitrile, to its corresponding quinone derivative in aerial oxygen. The reaction follows Michaelis-Menten enzymatic reaction kinetics with turnover numbers (Kcat) 7.51 × 102, 1.69 × 103 and 1.23×103h−1 in methanol, dichloromethane and acetonitrile, respectively. A dinuclear Fe(III) complex, [FeIII2(L)2] (1) [H3L=N,N′-bis(3-methoxysalicylaldimine)-1,3-diaminopropan-2-ol], has been synthesized and characterized using microanalysis, spectroscopy and X-ray crystallography. Structural analysis reveals a pentadentate chelation behaviour of the trianionic ligand H3L, having a distorted octahedral coordination environment around each iron(III) center with an FeN2O4 chromophore. Variable-temperature magnetic susceptibility measurements of 1 indicate an antiferromagnetic interaction between the two iron(III) centers, coupled with J=−28.5. 1 behaves as an effective catalyst towards the oxidation of 3,5-di-tert-butylcatechol in different solvents, viz. methanol, dichloromethane and acetonitrile, to its corresponding quinone derivative in aerial oxygen. The reaction follows Michaelis-Menten enzymatic reaction kinetics with turnover numbers (Kcat) 7.51×102, 1.69×103 and 1.23×103h−1 in methanol, dichloromethane and acetonitrile, respectively.