Frontispiece: An Octanuclear Metallosupramolecular Cage Designed To Exhibit Spin-Crossover Behavior

Ein achtkerniger metallosupramolekularer Würfel mit Spin-Crossover-Eigenschaften

A PAS domain with an oxygen labile [4Fe-4S](2+) cluster in the oxygen sensor kinase NreB of Staphylococcus carnosus.

The cytoplasmic histidine sensor kinase NreB of Staphylococcus carnosus responds to O(2) and controls together with the response regulator NreC the expression of genes of nitrate/nitrite respiration. nreBC homologous genes were found in Staphylococcus strains and Bacillus clausii, and a modified form was found in some Lactobacillus strains. NreB contains a sensory domain with similarity to heme B binding PAS domains. Anaerobically prepared NreB of S. carnosus exhibited a (diamagnetic) [4Fe-4S](2+) cluster when assessed by Mossbauer spectroscopy. Upon reaction with air, the cluster was degraded with a half-life of approximately 2.5 min. No significant amounts of Mossbauer or EPR detectable i…

An Octanuclear Metallosupramolecular Cage Designed To Exhibit Spin-Crossover Behavior.

By employing the subcomponent self-assembly approach utilizing 5,10,15,20-tetrakis(4-aminophenyl)porphyrin or its zinc(II) complex, 1H-4-imidazolecarbaldehyde, and either zinc(II) or iron(II) salts, we were able to prepare O-symmetric cages having a confined volume of ca. 1300 Å3 . The use of iron(II) salts yielded coordination cages in the high-spin state at room temperature, manifesting spin-crossover in solution at low temperatures, whereas corresponding zinc(II) salts led to the corresponding diamagnetic analogues. The new cages were characterized by synchrotron X-ray crystallography, high-resolution mass spectrometry, and NMR, Mössbauer, IR, and UV/Vis spectroscopy. The cage structures…

CCDC 1451726: Experimental Crystal Structure Determination

Related Article: Niklas Struch, Christoph Bannwarth, Tanya K. Ronson, Yvonne Lorenz, Bernd Mienert, Norbert Wagner, Marianne Engeser, Eckhard Bill, Rakesh Puttreddy, Kari Rissanen, Johannes Beck, Stefan Grimme, Jonathan R. Nitschke, Arne Lützen|2017|Angew.Chem.,Int.Ed.|56|4930|doi:10.1002/anie.201700832