ic025674k_si_001.cif (22.05 kB)

Synthesis, Structure, Properties, and Phosphatase-Like Activity of the First Heterodinuclear FeIIIMnII Complex with the Unsymmetric Ligand H2BPBPMP as a Model for the PAP in Sweet Potato

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posted on 06.08.2002 by Peter Karsten, Ademir Neves, Adailton J. Bortoluzzi, Mauricio Lanznaster, Valderes Drago
The new heterodinuclear mixed valence complex [FeIIIMnII(BPBPMP)(OAc)2]ClO4 (1) with the unsymmetrical N5O2 donor ligand 2-bis[{(2-pyridylmethyl)-aminomethyl}-6-{(2-hydroxybenzyl)(2-pyridylmethyl)}-aminomethyl]-4-methylphenol (H2BPBPMP) has been synthesized and characterized. Compound 1 crystallizes in the monoclinic system, space group P21/c, and has an FeIIIMnII(μ-phenoxo)-bis(μ-carboxylato) core. Two quasireversible electron transfers at −870 and +440 mV versus Fc/Fc+ corresponding to the FeIIMnII/FeIIIMnII and FeIIIMnII/FeIIIMnIII couples, respectively, appear in the cyclic voltammogram. The dinuclear FeIIIMnII center has weakly antiferromagnetic coupling with J = −6.8 cm-1 and g = 1.93. The 57Fe Mössbauer spectrum exhibits a single doublet, δ = 0.48 mm s-1 and ΔEQ = 1.04 mm s-1 for the high spin FeIII ion. Phosphatase-like activity at pH 6.7 with the substrate 2,4-bis(dinitrophenyl)phosphate reveals saturation kinetics with the following Michaelis−Menten constants:  Km = 2.103 mM, Vmax = 1.803 × 10-5 mM s-1, and kcat = 4.51 × 10-4 s-1.