Synthesis,characterization, and magnetochemical properties of two Mn4 clusters derived from 2-pyridinecarboxaldehyde Schiff base ligands |
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| Authors: | He Tian Xin Qiao Cheng-Zhi Xie |
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| Affiliation: | Department of Chemical Biology and Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics, School of Pharmacy, Tianjin Medical University, Tianjin, PR China |
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| Abstract: | Two tetranuclear manganese complexes, [Mn4(L1)6](ClO4)2?2.75H2O (1) [HL1 = 4-methyl-2-((pyridin-2-ylmethylene)amino)phenol] and [Mn4(L2)4(NO3)3(OH)]?pz?3H2O (2) [HL2 = (1H-pyrazol-1-yl)(pyridin-2-yl)methanol, pz = pyrazole], have been synthesized and characterized by IR spectroscopy, elemental analysis, single-crystal X-ray diffraction, and magnetic measurements. The structural analysis revealed that the central manganese ion is linked with three apical manganese ions through six phenoxo-bridges creating a Mn4O6 core for 1; 2 has a cubane-like topology with the Mn(II) ions and the deprotonated oxygens from L2 alternatively occupying vertices. The magnetic studies indicated a weak ferromagnetic coupling interaction (J = 0.48 ± 0.087 cm?1, g = 2.00, θ = ?0.78 K) for 1 and a weak antiferromagnetic spin-exchange interaction (J1 = ?0.50 ± 0.075 cm?1, J2 = ?0.13 ± 0.082 cm?1, g = 1.98) between Mn(II) ions for 2. The magnetostructural correlations of the two Mn4 clusters have been discussed tentatively. |
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| Keywords: | Manganese cluster Schiff base ligand X-ray crystallography magnetic properties |
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