Synthese und Funktionalisierung von Verbindungen mit binären, ternären und quaternären Chalkogenidometallat-Anionen in ionischen Flüssigkeiten

Die im Rahmen dieses Promotionsprojektes erhaltenen Ergebnisse werden gemäß dem Arbeitstitel thematisch in zwei Bereiche unterteilt: Die Synthese von neuartigen Verbindungen mit Chalkogenidometallat-Anionen (1) und die Funktionalisierung an Chalkogenidometallat-Anionen (2). Als Reaktionsmedium wurden in beiden Fällen ionische Flüssigkeiten (ILs) eingesetzt. (1) Durch die Wahl geeigneter Additive (wie SbCl3) können entsprechende (Halb )Metallatome in die Strukturen der Chalkogenidometallat-Verbindungen eingebaut werden. Dies konnte anhand der Verbindungen 12, 2a2 und 2b2 gezeigt werden, die ein [Ge2Sb2S7]6[GeS4]-Aggregat (12) beziehungsweise ein {[Sn10O4S20][Sb3S4]2}-Anionengerüst (22) enthalten. Am Beispiel der Netzwerkstrukturen in {(C4C1C1Im)2[Sn3S7]} (1a3), {(C4C1C2Im)2[Sn3S7]} (1b3) und {(C4C1C2Im)2[Sn4S9]} (23) wurde der Einfluss des IL-Kations untersucht. 1b3 kann zudem innerhalb von Minuten durch Kationenaustausch in 1a3 umgewandelt werden. Auch bei der Bildung von (C14C1Im)8[Hg8Te16] (4) und (C16C1Im)8[Hg8Te16] (5) spielt die Wahl des Imidazoliumkations eine Rolle. Es handelt sich dabei um Verbindungen, in denen das literaturbekannte [Hg8Te16]8–-Porphyrinoidanion in eine lamellare Doppelschicht aus Imidazoliumkationen eingebettet ist. (2) Der Einsatz von (C4C1C1Im)Cl oder (C4C4C1Im)Cl lieferte mit (C4C1C1Im)4[Sn10O4S16(SMe)4] (15) und (C4C4C1Im)4[Sn10O4S16(SMe)4] (16) Verbindungen mit methylierten Oxothiostannat-Anionen (OTS-Anion). Mit SnCl4 als Additiv konnte (C4C1Im)4[Sn10O4S16(SH)4] (2) und damit eine Verbindung mit protoniertem OTS Anion erhalten werden. Die Reaktion von K4[SnS4]∙4H2O mit (C4C1C4Im)Br führte schließlich zu (C4C1C4Im)4[Sn10O4S16(SBu)4] (1a) mit butyliertem OTS-Anion als Reaktionsprodukt. Diese Verbindung ist im Gegensatz zu allen bisher beschriebenen und hier vorgestellten Verbindungen dieser Verbindungsklasse in organischen Lösungsmitteln löslich (z.B. Acetonitril). Zudem konnte anhand der Synthese von (C10C1Im)6[Hg6Te10(TeDec)2] (3) gezeigt werden, dass Decylierungen von Chalkogenidometallat-Anionen möglich sind. 3 weist eine für Exfoliation günstige lamellare Kristallstruktur auf

Hodge structures of the moduli spaces of pairs

Let $X$ be a smooth projective curve of genus $g\geq 2$ over the complex numbers. Fix $n\geq 2$, and an integer $d$. A pair $(E,\phi)$ over $X$ consists of an algebraic vector bundle $E$ of rank $n$ and degree $d$ over $X$ and a section $\phi$. There is a concept of stability for pairs which depends on a real parameter $\tau$. Let $M_\tau(n,d)$ be the moduli space of $\tau$-semistable pairs of rank $n$ and degree $d$ over $X$. We prove that the cohomology groups of $M_\tau(n,d)$ are Hodge structures isomorphic to direct summands of tensor products of the Hodge structure $H^1(X)$. This implies a similar result for the moduli spaces of stable vector bundles over $X$.Comment: 23 page

Extent of microplastics in Pacific Sand Lance burying habitat in the Salish Sea

Extent of microplastics in Pacific Sand Lance burying habitat in the Salish Sea Willem Peters MRM candidate Simon Fraser University, Dr. Cliff Robinson Department of Fisheries and Oceans, Dr. Karen Kohfeld Simon Fraser University, Dr. Marlow Pellatt Parks Canada, Dr. Doug Bertram Environment and Climate Change Canada School of Resource and Environmental Management, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6 CANADA, [email protected] The ingestion of microplastics by forage fish and their subsequent accumulation and transfer up the coastal food web is a growing concern to scientists, government, fisheries, and the health sector. One key forage species in the Salish Sea, the Pacific sand lance (Ammodytes personatus), buries in low silt, medium coarse sand patches from chart datum to 100 m depth. In the southern Salish Sea near Sidney, several of these burying habitats are located in the vicinity of sewage discharge pipes and may be subject to microplastic accumulation. This research assesses the level of microplastic accumulation in Pacific sand lance burying habitats in the Salish Sea. Seafloor sediment samples were collected in Spring-Fall 2017, using a Van Veen grab sampler. Samples were collected at different distances from shore and effluent discharge pipes, and from a variety of depths and tidal currents. Microplastic concentrations were determined from the sediment samples in the laboratory using standard methods, while controlling for contamination. The main results indicate a significant correlation between suitable Pacific sand lance burying habitat and higher microplastic concentrations. We also found a strong imbalance of microplastic type and colour, with blue fibres making up the majority of microplastics found. The relationship between microplastics and Pacific sand lance habitat suitability is not intuitive in that higher concentrations of microplastics were found in sediments that suggest higher current rates, where settling dynamics would suggest that fewer particles would settle. Possible explanations include evacuation of microplastics from sand lance when buried, the proximity of suitable habitat to effluent discharge, or other as yet unexplored factors. Overall, the presence of microplastics in the burying habitats and stomachs of Pacific sand lance (as noted in other research) indicates more research is required to understand the implication to higher trophic level species that feed upon Pacific sand lance, such as chinook and coho salmon, various groundfish, fish-eating alcids, and marine mammals such as the humpback whale. Ultimately, strategies to reduce microplastics entering the Salish Sea will need to be implemented

Large-scale synthesis of mixed valence K3_3[Fe2_2S4_4] with high dielectric and ferrimagnetic characteristics

High yields of phase-pure K(3)[Fe(2)S(4)] are obtained using a fast, straight-forward, and efficient synthetic technique starting from the binary precursors K(2)S and FeS, and elemental sulphur. The compound indicates soft ferrimagnetic characteristics with magnetization of 15.23 A m(2) kg(−1) at 300 K due to the mixed valence of Fe(II)/Fe(III). Sintering at different temperatures allows the manipulation of the microstructure as well as the ratio of grains to grain boundaries. This results in a variation of dielectric and impedance properties. Samples sintered at 923 K demonstrate a dielectric constant (κ) of around 1750 at 1 kHz, which lies within the range of well-known high-κ dielectric materials, and an ionic conductivity of 4 × 10(−2) mS cm(−1) at room temperature. The compound has an optical band gap of around 2.0 eV, in agreement with tailored quantum chemical calculations. These results highlight its potential as a material comprising non-toxic and abundant elements for electronic and magnetic applications