Amine-Templated Manganese Fluoride Sulfates with Butterfly Clusters: Synthesis, Structure, and Magnetic Properties

Two amine-templated manganese complexes are synthesized via a one-pot solvothermal process of the formulas {[((CH3)2NH2)4(C3H5N2)3][Mn4(SO4)6F3]·2(H2O)}n, 1 and {[(CH3)2NH2]2[Mn4(SO4)4F2(C4H4N2)]}n, 2. Both possess similar butterfly-shaped tetrameric clusters connected by μ2-F in 1 and pyrazine in 2, which are further linked by coordinated sulfates, leading to a helical chain in 1 and a three-dimensional (3D) network in 2. The dc-magnetic results show intercluster coupling in both compounds. The susceptibility, as well as isothermal magnetization, indicates the presence of intercluster long-range ferrimagnetic ordering for 1 and antiferromagnetic ordering for 2. The first-principles calculations revealed a ferrimagnetic ground state for the isolated tetrameric cluster in both 1 and 2. However, compound 1 exhibits a ferromagnetic ground state, whereas 2 exhibits an antiferromagnetic ground state by considering the intercluster exchange interaction through bridging F and pyrazine for 1 and 2, respectively.