1. Binuclear Manganese Compounds of Potential Biological Significance. 1. Syntheses and Structural, Magnetic, and Electrochemical Properties of Dimanganese(II) and -(II,III) Complexes of a Bridging Unsymmetrical Phenolate Ligand.
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Dubois, Lionel, Dao-Feng Xiang, Xian-Shi Tan, Pécaut, Jacques, Jones, Peter, Baudron, Stéphane, Le Pape, Laurent, Latour, Jean-Marc, Baffert, Carole, Chardon-Noblat, Sylvie, Collomb, Marie-Noëlle, and Deronzier, Alain
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MANGANESE compounds , *LIGANDS (Chemistry) , *PHENOLS - Abstract
Reactions of the unsymmetrical phenol ligand 2-(bis(2-pyridyimethyl)aminomethyl)-6-((2-pyridylmethyl)(benzyl)aminometh yl)-4-methylphenol with Mn(OAc)[sub 2]·4H[sub 2]O or Mn(H[sub 2]O)[sub 6](ClO[sub 4])[sub 2] in the presence of NaOBz affords the dimanganese(II) complexes 1(CH[sub 3]OH), [Mn[sub 2](L)(OAc)[sub 2](CH[sub 3]OH)](ClO[sub 4]), and 2(H[sub 2]O), [Mn[sub 2](L)(OBz)[sub 2](H[sub 2]O)](ClO[sub 4]), respectively. On the other hand, reaction of the ligand with hydrated manganese(III) acetate furnishes the mixedvalent derivative 3(H[sub 2]O), [Mn[sub 2](L)(OAc)[sub 2](H[sub 2]O)](ClO[sub 4])[sub 2]. The three complexes have been characterized by X-ray crystallography. 1(CH[sub 3]OH) crystallizes in the monoclinic system, space group P2[sub 1]/c, with a = 10.9215(6) Å, b = 20.2318(12) Å, c = 19.1354(12) Å, α = 90°, β = 97.5310(10)°, γ = 90°, V = 4191.7 A³, and Z = 4. 2(H[sub 2]O) crystallizes in the monoclinic system, space group P2[sub 1]/n, with a = 10.9215(6) Å, b = 20.2318(12) Å, c = 19.1354(12) Å, α = 90°, β = 97.5310(10)°, γ = 90°, V = 4191.7 ų, and Z = 4.3(H[sub 2]O) crystallizes in the monoclinic system, space group P2[sub 1]/c, with a = 11.144(6) Å, b = 18.737(10) Å, c = 23.949(13) Å, α = 90°, β = 95.910(10)°, γ = 90°, V-4974(5) ų, and Z = 4. Magnetic measurements revealed that the three compounds exhibit very similar magnetic exchange interactions -J = 4.3(3) cm[sup -1]. They were used to establish tentative magnetostructural correlations which show that for the dimanganese(II) complexes -J decreases when the Mn-O[sub phenoxo] distance increases as expected from orbital overlap considerations. For the dimanganese(II,III) complexes, crystallographic results show that the Mn[sup II]-O[sub phenoxo] and Mn[sup III]-O[sub phenoxo] bond lengths are inversely correlated. An... [ABSTRACT FROM AUTHOR]
- Published
- 2003
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