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

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 × 103 h−1 in methanol, dichloromethane and acetonitrile, respectively.

Graphical abstractA 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 × 103 h−1 in methanol, dichloromethane and acetonitrile, respectively.Figure optionsDownload full-size imageDownload as PowerPoint slide