The palladium(II)‐containing 40‐tungsto‐4‐arsenate(III) [Pd2Na2KAs4W40O140(H2O)]21– (1a) was synthesized by reaction of PdSO4 with the cryptate heteropolyanion [As4W40O140]28– in potassium acetate buffer. The title compound was characterized by single‐crystal XRD, IR, TGA, and elemental analysis.

The assessment of leukocyte activation in vivo is mainly based on surrogate parameters, such as cell shape changes and migration patterns. Consequently, additional parameters are required to dissect the complex spatiotemporal activation of leukocytes during inflammation. Here, we showed that intravital microscopy of myeloid leukocyte Ca 2+ signals with Ca 2+ reporter mouse strains combined with bioinformatic signal analysis provided a tool to assess their activation in vivo. We demonstrated by two-photon microscopy that tissue-resident macrophages reacted to sterile inflammation in the cremaster muscle with Ca 2+ transients in a distinct spatiotemporal pattern. Moreover, through high-resolution, intravital spinning disk confocal microscopy, we identified the intracellular Ca 2+ signaling patterns of neutrophils during the migration cascade in vivo. These patterns were modulated by the Ca 2+ channel Orai1 and Gα i -coupled GPCRs, whose effects were evident through analysis of the range of frequencies of the Ca 2+ signal (frequency spectra), which provided insights into the complex patterns of leukocyte Ca 2+ oscillations. Together, these findings establish Ca 2+ frequency spectra as an additional dimension to assess leukocyte activation and migration during inflammation in vivo.

The cover picture, created by Dr. Rami Al‐Oweini, shows the careful insertion of palladium(II) ions into the polyoxometalate (POM) host [As4W40O140]28– (As4W40). In total two Pd2+ ions have been incorporated, resulting in the novel polyanion [Pd2Na2KAs4W40O140(H2O)]21– (Pd2As4W40). The insertion of noble metals (e.g. Pd, Pt, Au) into POMs is rather difficult and hence the proper reaction conditions must be carefully identified. Pd2As4W40 represents the first structurally characterized noble metal derivative of As4W40. This work paves the way for the insertion of other d8 noble metal ions into As4W40. More details can be found in the article by Zhengguo Lin, Natalya V. Izarova, Fitsumbirhan T. Mehari, and Ulrich Kortz on page http://onlinelibrary.wiley.com/doi/10.1002/zaac.201800327/abstract.