Sergei I. Ivlev

Br2F7− and Br3F10−: peculiar anions showing μ2- and μ3-bridging F-atoms

RbCl and CsCl react with BrF3 yielding the corresponding decafluoridotribromates(iii), MBr3F10 (M = Rb, Cs), which were structurally characterized for the first time. The Br3F10- anion is surprisingly not linear but contains a μ3-bridging fluorine atom and seems to be the first example of μ3-F bridging of Br atoms. The compounds are highly reactive and cannot be handled in glassware. As for the tetrafluoridobromates themselves, they are powerful oxidizers and thus suitable for the dry-chemical recycling of precious metals and additionally feature a significantly higher BrF3 content.

3D biodegradable scaffolds of polycaprolactone with silicate-containing hydroxyapatite microparticles for bone tissue engineering: high-resolution tomography and in vitro study

To date, special interest has been paid to composite scaffolds based on polymers enriched with hydroxyapatite (HA). However, the role of HA containing different trace elements such as silicate in the structure of a polymer scaffold has not yet been fully explored. Here, we report the potential use of silicate-containing hydroxyapatite (SiHA) microparticles and microparticle aggregates in the predominant range from 2.23 to 12.40 µm in combination with polycaprolactone (PCL) as a hybrid scaffold with randomly oriented and well-aligned microfibers for regeneration of bone tissue. Chemical and mechanical properties of the developed 3D scaffolds were investigated with XRD, FTIR, EDX and tensile testing. Furthermore, the internal structure and surface morphology of the scaffolds were analyzed using synchrotron X-ray µCT and SEM. Upon culturing human mesenchymal stem cells (hMSC) on PCL-SiHA scaffolds, we found that both SiHA inclusion and microfiber orientation affected cell adhesion. The best hMSCs viability was revealed at 10 day for the PCL-SiHA scaffolds with well-aligned structure (~82%). It is expected that novel hybrid scaffolds of PCL will improve tissue ingrowth in vivo due to hydrophilic SiHA microparticles in combination with randomly oriented and well-aligned PCL microfibers, which mimic the structure of extracellular matrix of bone tissue.

The Interhalogen Cations [Br2F5]+ and [Br3F8]+

The synthesis and characterization of unique polyhalogen cations containing μ-bridging fluorine atoms are reported. The [Br2 F5 ]+ cation features a symmetric [F2 Br-μ-F-BrF2 ] bridge, whereas the [Br3 F8 ]+ contains asymmetric μ-F bridges. These fluoronium ions, obtained as [SbF6 ]- salts, were investigated using Raman and 19 F NMR spectroscopy, as well as single-crystal X-ray diffraction. Quantum chemical calculations were carried out for the gas-phase cations as well as for the solid-state compounds. Population analyses show the μ-F atoms to possess the most negative partial charge within the cations.

Br 2 F 7 - and Br 3 F 10 -

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