Constructing anhydrous halide bridged manganese(II) clusters: Synthesis, structures and magnetic properties

•We have prepared five new anhydrous halide bridged manganese(II) clusters.•The triphenylacetate is used as a bridging as well as terminal ligand.•The strong antiferromagnetic exchange is observed for all compounds.

The reaction of Mn0 and HgCl2 with triphenylacetic acid in a mixture of 2-methoxyethanol and toluene afforded complex [Mn2IICl2(O2CCPh3)2(2-methoxyethanol)3] (1) in very good yield. Repeating the same reaction and replacing 2-methoxyethanol with THF forms the complex [Mn3IICl3.04(O2CCPh3)1.96(2-methoxyethanol)(THF)4] (2) in good yield. Furthermore the reaction between Mn0 and triphenylacetic acid in a mixture of THF and toluene after heating produces the complex [Mn4Cl5Na(O2CCPh3)4(THF)6] (3). Finally, the reaction between MnCl2 and potassium triphenylacetate or lithium triphenylacetate in THF and toluene gave complexes [Mn4Cl5K(O2CCPh3)4(THF)6] (4) and [Mn4Cl5Li(O2CCPh3)4(THF)5]·0.75(THF) (5·0.75THF), respectively, in good yields. The crystal structures of 1–5 have been determined by single-crystal X-ray crystallography. Complex 1 is a chloride bridged [MnII2] dimer in which the two metal ions are found in an O5Cl and an O3Cl2 coordination environment. Complex 2 is a trinuclear [MnII3] triangle-like cluster in which the “central” MnII ion is bridged via two chloride ions to the peripheral Mn2+ ions, additionally all manganese ions are connected by oxygen ion in a μ3 mode. Complexes 3–5 are all tetranuclear [MnII4Cl5]3+ metallic clusters displaying similar geometries, in which the tetrametallic core unit possesses a planar square arrangement. DC magnetic susceptibility studies indicate the presence of dominant antiferromagnetic exchange for all 1–4 clusters.

Graphical abstractFive new anhydrous polynuclear manganese(II) triphenylacetate complexes with Mn2Cl, Mn3Cl2O and Mn4Cl4Cl′, M (M = Li, Na, K), 1–5 respectively, were obtained and characterized by single crystal X-ray and magnetic study.Figure optionsDownload full-size imageDownload as PowerPoint slide