Magnetic moments: The orientation of the title single‐molecule magnet was investigated by magnetic single crystal and luminescence characterization, supported by ab initio calculations, and was found to be governed by the position of the hydrogen atoms of the apical water molecules. This finding suggests that simple magneto‐structural correlations can give misleading clues for research in molecular magnetism as well as in the design of MRI contrast agents.

The trivacant triruthenium-substituted polyoxometalate α-K 6 Na[{Ru 3 O 3 (H 2 O)Cl 2 }(SiW 9 O 34 )]•17H 2 O (1) and two sandwich-type Co-and Ni-containing silicotungstates K 11 Na 1) based on the same Keggin-type building block were obtained through variation of a solution-based protocol. All compounds were investigated with respect to their performance as visiblelight-driven water oxidation catalysts (WOCs). Analytical characterizations and photocatalytic reactivity of (1) are correlated with results of B97D/Def2-TZVP computation. The WOC activity of (1) and (2) was found to arise from their immobilization into a recyclable POM-photosensitizer complex (POM-PS). These POM-PS complexes are formed in the initial phase of the reaction, and they prevent POM decomposition into colloidal oxide catalysts. † Electronic supplementary information (ESI) available: Synthetic and computational methods, FT-IR/Raman/UV-vis spectra, thermogravimetric studies, cyclic voltammetry measurements, ESI-MS and lightinduced water-oxidation studies. See

The square antiprismatic Na[Dy(DOTA)(H(2)O)]·4H(2)O complex was characterised by single crystal X-ray diffraction and ac magnetic susceptometry. Two competing mechanisms for magnetic relaxation as well as the remarkable increase of six orders of magnitude in the relaxation time upon application of a static magnetic field were detected.