Hexanuclear and Tetranuclear Mn/Ln clusters using 2‐(hydroxymethyl)pyridine: Synthesis, structures and magnetic properties

Reactions of manganese benzoate dihydrate and lanthanide nitrate hexahydrate with 2‐(hydroxymethyl)pyridine (hmpH) as ligand in the mixture solutions of acetonitrile and ethanol according to different molar ratios of NEt3 generated two kinds of Mn‐Ln compounds [MnIII4LaIII2(O)2(hmp)7(PhCO2)2(NO3)5] ·5H2O (1) and [MnIII2GdIII2(hmp)6(PhCO2)4(NO3)2] ·3CH3CN·3C2H5OH·2H2O (2). By comparison of the two compounds, there exist considerable effects of reaction alkalinity on the structures and magnetic properties of products. Compound 1 possesses a core of [MnIII4LaIII2(μ4‐O)(μ3‐O)(μ3‐OR)(μ2‐O)7]2−, which comprises three face‐sharing defected cubane units. The core topology represents a new core type of Mn‐Ln clusters. Compound 2 has a planar‐butterfly structure. The solid‐state dc magnetic susceptibility analyses indicate the antiferromagnetic interactions within compound 1 and ferromagnetic interactions within compound 2. Compound 1 has an S = 0 ground state, while compound 2 possesses an S = 11 ground state, fitting of the dc data for the tetranuclear Mn2Gd2 with the Magpack program gives parameters of JMn‐Mn = 3.11 cm−1, JMn‐Gd = 0.02 cm—1 and g = 1.96. The hexanuclear and tetranuclear compounds were synthesized by the same reaction except alkalinity reaction condition. By comparsion of the two compounds, there exist considerable effects of alkalinity on the structures and magnetic properties of compounds.