Environmental Influence on the Single-Molecule Magnet Behavior of [MnIII6CrIII]3+: Molecular Symmetry versus Solid-State Effects

The structural, spectroscopic, and magnetic properties of a series of [MnIII6CrIII]3+ (= [{(talent-Bu2)MnIII3}2{CrIII(CN)6}]3+) compounds have been investigated by single-crystal X-ray diffraction (XRD), Fourier transform infrared (FT-IR) and electronic absorption spectroscopy, elemental analysis, electro spray ionization–mass spectrometry (ESI-MS) and matrix-assisted laser desorption ionization–mass spectrometry (MALDI-MS), cyclic voltammetry, AC and DC magnetic measurements, as well as theoretical analysis. The crystal structures obtained with [CrIII(CN)6]3– as a counterion exhibit (quasi-)one-dimensional (1D) chains formed by hydrogen-bonded (1) or covalently linked (2) trications and trianions. The rod-shaped anion lactate enforces a rod packing of the [MnIII6CrIII]3+ complexes in the highly symmetric space group R3 (3) with a collinear arrangement of the molecular S6 axes. Incorporation of the spherical anion BPh4– leads to less-symmetric crystal structures (4–6) with noncollinear orientations of th...