Synthesis, crystal structure and magnetic properties of an enneanuclear manganese cluster containing mixed chelating ligands

A new mixed-valence [Mn9] cluster of formulae [Mn9O(OH)3Cl4(N3)3(hmp)6(dpkd)3]·1.5CH3CN·3H2O (1·1.5CH3CN·3H2O, where hmp− and dpkd2− are the anion of 2-hydroxymethylpyridine and the dianion of the gem-diol form of the dpk, respectively) has been synthesized and characterized by single-crystal X-ray diffraction, IR spectra, elemental analysis and magnetic measurements. Single-crystal structural analysis shows that complex 1 contains a [Mn9] core with a new structural topology in the Mn clusters, in which the centered six MnIII atoms compose a trigonal antiprism and the peripheral residual three MnII atoms can be seen as the skirt hem of this antiprism. DC magnetic susceptibility studies indicate that the overall antiferromagnetic interactions between Mn ions are present in the cluster. Fitting the data of magnetization and extrapolation of the χM′T suggest the spin ground states of S = 3.5, and no out-of-phase (χM″) signals are present in the alternating current (AC) susceptibility.

A new topology MnIII6MnII3 cluster containing mixed chelating ligands has been obtained. The complex is entirely antiferromagnetically coupled, possessing the possible S = 3.5 ground state.Figure optionsDownload as PowerPoint slideHighlights
► We have synthesized a Mn9 cluster containing mixed chelating ligands.
► The core of the cluster possesses a new structural topology in the Mn clusters.
► The Jahn–Teller axes of MnIII are almost perpendicular to each other.
► Predominant antiferromagnetic coupling interactions between Mn atoms are present.