| Since R. Sessoli et al. observed single-molecular magnetic behavior on Mn12-Ac in 1993, the reseach on single molecular mangnets (SMMs) derived from manganese clusters has received much attention. In this paper, the SMMs based on manganese-containing complexes are summarized and several manganese complexes derived of multi-dentate ligands with pendant are designed and synthesized to acquire SMMs. The main work is listed as follows:1. Six ligands, HL1 (1-methyl-2,3-dihydro-1H-imidazol-2-yl), HL2 (1H-benzoimidazol -2-yl)methanol, HL3 (1-methyl-2,3-dihydro-1H-imidazolecarbal-dehydeoxime), H2L4 (3,5-dibromo-2-hydroxybenzylidene)-4-hydroxybenzohydrazide), TPMBr (tris-(4-bromo-1H-pyrazol-1-yl)methane) and L5 (di-(2-benzimidazolymethyl)amine) have been synthesized and characterized by elemental analysis, IR, MS, and 1H NMR.2. Six Mn-containing complexes with these ligands, [Mn2ⅡMn2Ⅲ(L1)6(N3)4]·(DMF)3 (1), [Mn4ⅡMn3Ⅲ(L2)12](ClO4)5·(Et2O)2·(CH3CN)·(H2O)4 (2), [Mn(L3)2(H2O)2]ClO4 (3), [Mn(L3)2(DMF)2]ClO4 (4), [Mn(L5)2](ClO4)2 (5), [Mn(bipy)2(N3)2] (6), have been synthesized and characterized by X-ray diffraction, IR and elemental analysis. The cyclic voltammogram and magnetic properties of some complexes have been studied.3. Complex 1 crystallized in the triclinic space group P1- with a = 10.7017(12), b = 11.9629(14), c = 12.3674(14), a = 76.052(2), p = 76.400(2),γ= 86.822(2)°. The crystal structure of 1 showed that there are four manganese atoms with a "butterfly-like" core in the structure. The variable temperature magnetic susceptibility of 1 indicates the existence of intramolecular weak antiferromagnetic interaction at low temperature.4. Complex 2 crystallized in the monoclinic space group P21/n with a = 21.051(5), b = 28.373(7), c = 21.975(6) (?),β= 111.622(4)°. The crystal structure of 2 showed that the cation consists of four MnⅡand three MnⅢions, arranged as a Mn6 hexagon of alternating MnⅡand MnⅢions surrounding a central MnⅡion. The variable temperature magnetic susceptibility of 2 manifests the existence of dominant intramolecular ferromagnetic interaction in the complex.5. Complexes 3, 4, 5 and 6 are mononuclear manganese compounds in which the valence states of the metal centers are +3 for 3 and 4, +2 for 5 and 6, respectively. |
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