摘要：

The reaction of Mn(O2CCH3)3 ·2H2O with the ligand N,N-bis(2-pyridylmethyl)ethylamine (bpea) in a 1:1 ratio in methanol followed by the addition of NaClO4 afforded the title compound [Mn2O(O2CCH3)2(bpea)2](ClO4)2 (1) in 75% yield. Compound 1 was characterized by using several physical methods including single-crystal X-ray diffractometry. Compound 1·0.5H2O crystallizes in the orthorhombic space group Pbca (No. 61) with a = 38.780(2), b = 22.058(4), c = 19.719(5) A, V = 16 868(8) A3 and Z = 16. There are two independent equivalents of compound 1 in the crystallographic asymmetric unit and there is a single unique water molecule in the crystal lattice. Both manganese atoms in each of the independent dinuclear units are in the +3 oxidation state and they are bridged by one oxo ligand (O2) and two acetate groups. Each manganese atom is also bound to one facially-coordinating tridentate bpea ligand, with the aliphatic nitrogen donor situated trans to an acetate oxygen atom. Deviations from idealized octahedral symmetry at each manganese center are consistent with expectations for a d4 electronic configuration. Compound 1 has an average Mn…Mn separation of 3.11 and an average Mn(μ-O)Mn angle of 122.7°. The electronic absorption spectrum of 1 in CH3CN is very similar to other compounds that contain the {Mn2(μ-O)(μ-O2CCH3)2}2+ core. A cyclic voltammogram of 1 in CH3CN exhibits an oxidation wave (III,III to III,IV) at +0.66 V and a reduction wave (III,III to III,II) at 0.39 V versus the ferrocene/ferrocenium (Fc/Fc+) couple. The IR spectrum of 1 reveals two strong bands at 1566 and 1432 cm1 corresponding to the bridging acetate groups present in the compound. The X-band electron paramagnetic resonance (EPR) spectrum of 1 in dry CH3CN at 77 and 4 K is featureless. Compound 1 disproportionates in an H2O/CH3CN solvent mixture to give the (III,IV) binuclear species [Mn2O2(O2CCH3)(bpea)2] 2+, which displays a characteristic 16-line g = 2 EPR signal.

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