Synthesis and Characterization of the Di(μ-oxo)Dimanganese(III,IV) Complex with Carboxylato Groups as a Terminal Ligand

Abstract

A dinuclear manganese(III,IV) mixed valence complex [Mn2(N3O-py)2(O)2]ClO4·2.5H2O was prepared (N3O-py:N,N-bis(2-pyridylmethyl)glycinate) and its crystal structure was determined by X-ray crystal structure analysis. The analysis showed that two manganese ions are linked by two oxo bridges with the separation of 2.656(2) Å and the structural difference between manganese(III) and manganese(IV) moieties is relatively small compared to those of complexes so far reported.

Carboxylate Ligands Drastically Enhance the Rates of Oxo Exchange and Hydrogen Peroxide Disproportionation by Oxo Manganese Compounds of Potential Biological Significance

“…An excellent fit was obtained with the parameters listed in Table 2. The antiferromagnetic exchange interaction deduced from the simulation (ÀJ = 106 AE 1 cm À1 ) is slightly higher than those [24] (ÀJ = 86 cm [54] Similar assignments were proposed by Suzuki et al [35] for 1 and by Hodgson et al [24,28] for complexes of the bispicen and tpa series.…”

“…Mn III Mn IV complexes: The Mn 3 (1) [34] and [ [35] had already been described. To assess the influence of a greater number of carboxylate ligands, as found in the catalase enzymes, we decided to extend this series of compounds to the corresponding complexes of the H 2 pda and H 3 nta ligands.…”

“…By this method we succeeded in obtaining the bisA C H T U N G T R E N N U N G (m-oxo)-Mn III Mn III complexes of the ligands tpa and Hbpg (5 and 6, respectively), from their bisA C H T U N G T R E N N U N G (m-oxo)-Mn III Mn IV precursors. [34,35] With the ligand H 2 pda the obtained complex disproportionated into Mn…”

“…[28,31,35,[50][51][52][53] We studied the magnetic properties of complexes 1-3 to assess the influence of the peripheral tetradentate ligand on the magnetic interaction. Owing to the strong coupling for all complexes and the small range of variation, it was necessary to study the three compounds in spite of earlier measurements on 1-2.…”

“…Owing to the strong coupling for all complexes and the small range of variation, it was necessary to study the three compounds in spite of earlier measurements on 1-2. [35,50] Figure S2 illustrates the temperature dependence of the magnetic susceptibilities for all compounds studied. In the cases of 1-3, the product c M T is about 0.75 K cm 3 mol À1 at room temperature and decreases steadily with temperature until it reaches a plateau at c M T % 0.4 K cm 3 mol…”