A new topology of hexanuclear [MnIII4LnIII2] clusters: syntheses, structures, and magnetic properties

Abstract

Reactions of manganese nitrate and lanthanide nitrate hexahydrate with 2-(hydroxymethyl)pyridine (hmpH) and sodium propionate as co-ligands in the mixed solutions of acetonitrile and ethanol generated two hexanuclear Mn–Ln compounds [Mn₄Ln₂O₂(OH)(hmp)₅(EtCO₂)₃(MeCN)(NO₃)₅(H₂O)] [Ln = La (1), Nd (2)]. Compounds 1 and 2 are isostructural and possess a core of [Mn^III₄Ln^III₂(μ₃-OR)₃(μ₃-O)₂(μ₂-O)₃]⁵⁺, which comprises three face-sharing defect cubane units. The core topology represents a new core type of Mn–Ln cluster. The soild-state dc magnetic susceptibility analyses indicate antiferromagnetic interactions within the two compounds. Compound 1 possesses an S = 0 ground state spin, fitting of the dc data for a tetranuclear Mn^III₄ with the Magpack program gives parameters of J₁ = −0.50 cm⁻¹, J₂ = −5.03 cm⁻¹, J₃ = 3.77 cm⁻¹ and g = 1.95.