0000000000406685
AUTHOR
Andreas F. Thünemann
Molecular switching complexes with iron and tin as central atom
Abstract The precursor [Fe III (L)Cl] (LH 2 = N , N ′-bis(2′-hydroxy-benzyliden)-1,6-diamino-3-N-hexane is a high-spin ( S = 5/2) complex. This precursor is combined with the bridging units [Sn IV (X) 4 ] (X = CN − , NCS − ) to yield star-shaped pentanuclear clusters, [(LFe III –X) 4 Sn]Cl 4 . For X = CN − the 57 Fe-Mossbauer data show a multiple spin transition between iron(III) in the high-spin and low-spin state, while the 119m Sn-Mossbauer data indicate a valence tautomerism between Sn(IV) and Sn(II). Changing the bridging unit from X = CN − to X = NCS − turns the switchability off.
Synthesis, characterization and fine-tuning of bimodal poly(organosiloxane) nanoparticles
Abstract The acid catalyzed sol–gel type synthesis of polyorganosiloxane core-shell nanoparticles with removable PDMS core in aqueous dispersion leads to the inherent formation of a bimodal size distribution with smaller spheres having approximately 26 nm radii and larger nanoparticles with 60 nm in radius. The origin of the self-organized bimodality is investigated and finally attributed to a combination of stabilization of the growing particles due to i) a miniemulsion-type stabilization by the ultrahydrophobe PDMS and ii) by surface co-stabilization by the employed surfactant. The significant influence of temperature, pH, stirrer speed and amount of the surfactant on the particle sizes a…
The solid-state architecture of a metallosupramolecular polyelectrolyte
Self-assembly of Fe(II) and the ditopic ligand 1,4-bis(2,2′:6′,2″-terpyridine-4′-yl)benzene results in equilibrium structures in solutions, so-called metallosupramolecular coordination polyelectrolytes (MEPEs). It is exceedingly difficult to characterize such macromolecular assemblies, because of the dynamic nature. Therefore, hardly any structural information is available for this type of material. Here, we show that from dilute solutions, where small aggregates predominate, it is possible to grow nanoscopic crystals at an interface. A near atomic resolution structure of MEPE is obtained by investigating the nanoscopic crystals with electron diffraction in combination with molecular model…