Browsing by Author "Bauch, Soeren"

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    Liquid crystalline self-assembly of mixtures of rod- and wedge-shaped MIDA boronates
    (2025) Schilling, Christopher; Bauch, Soeren; Wuckert, Eugen; Zens, Anna; Bruckner, Johanna R.; Laschat, Sabine
    Rod-like MIDA boronates form smectic mesophases, while wedge-shaped MIDA boronates self-assemble into columnar mesophases. However, the phase behavior of mixtures is less understood. In order to obtain further insight on the molecular self-assembly of MIDA boronate mixtures two series of binary mixtures of rod-like and wedge-shaped mesogens were prepared. The phase behavior was studied using differential scanning calorimetry (DSC), polarizing optical microscopy (POM) and X-ray diffraction (XRD). The study revealed a strong dependency of the mesophase structure on the mesogen composition. Usage of a less bulky columnar mesogen suppressed the formation of columnar mesophases in the mixture and led to a decrease in melting and clearing temperatures. The phase behavior is discussed in terms of the packing parameter model typically applied for lyotropic liquid crystals.
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    Synthesis and characterization of the amidomanganates Rb2[Mn(NH2)4] and Cs2[Mn(NH2)4]
    (2021) Bäucker, Christian; Bauch, Soeren; Niewa, Rainer
    We report the successful synthesis of Rb2[Mn(NH2)4] and Cs2[Mn(NH2)4] from ammonothermal conditions at 723 K and pressures above 850 bar. Both compounds were obtained single phase according to powder X-ray diffraction. The crystal structures were determined by single crystal X-ray diffraction. For Rb2[Mn(NH2)4] we have obtained the high-temperature phase. The structures are analyzed with respect to the earlier reported alkali metal amidomanganates. Upon heating in inert atmosphere Cs2[Mn(NH2)4] decomposes to manganese nitrides. IR spectroscopic results are reported.