Interconversion of one-dimensional Thiogallates Cs2[Ga2(S2)2-xS2+x] (x = 0, 1, 2) by using high-temperature Decomposition and Polysulfide-Flux Reactions

The potential of cesium polysulfide-flux reactions for the synthesis of chalcogenogallates was investigated by using X-ray diffraction and Raman spectroscopy. An investigation of possible factors influencing the product formation revealed that only the polysulfide content x in the Cs2Sx melts has an influence on the crystalline reaction product. From sulfur-rich melts (x > 7), CsGaS3 is formed, whereas sulfur-poor melts (x < 7) lead to the formation of Cs2Ga2S5- In situ investigations using high-temperature Raman spectroscopy revealed that the crystallization of these solids takes place upon cooling of the melts. Upon heating, CsGaS3 and Cs2Ga2S5 release gaseous sulfur due to the degradation of S-2(2-) units. This decomposition of CsGaS3 to Cs2Ga2S5 and finally to CsGaS2-mC16 was further studied in situ by using high-temperature X-ray powder diffraction. A combination of the polysulfide reaction route and the high-temperature decomposition leads to the possibility of the directed interconversion of these thiogallates. The presence of disulfide units in the anionic substructures of these thiogallates has a significant influence on the electronic band structures and their optical properties. This influence was studied by using UV/vis-diffuse reflectance spectroscopy and DFT simulations, revealing a trend of smaller band gaps with increasing S-2(2-) content

Whole-body integration of gene expression and single-cell morphology

Animal bodies are composed of cell types with unique expression programs that implement their distinct locations, shapes, structures, and functions. Based on these properties, cell types assemble into specific tissues and organs. To systematically explore the link between cell-type-specific gene expression and morphology, we registered an expression atlas to a whole-body electron microscopy volume of the nereid Platynereis dumerilii. Automated segmentation of cells and nuclei identifies major cell classes and establishes a link between gene activation, chromatin topography, and nuclear size. Clustering of segmented cells according to gene expression reveals spatially coherent tissues. In the brain, genetically defined groups of neurons match ganglionic nuclei with coherent projections. Besides interneurons, we uncover sensory-neurosecretory cells in the nereid mushroom bodies, which thus qualify as sensory organs. They furthermore resemble the vertebrate telencephalon by molecular anatomy. We provide an integrated browser as a Fiji plugin for remote exploration of all available multimodal datasets

Synthesis of silyl substituted organoboranes by hydroboration of vinylsilanes

Hydroboration reactions of dichloroborane-, monochloroborane- and borane-dimethylsulfide with dichloromethylvinylsilane and trichlorovinylsilane were investigated. The proposed structures of the produced organochlorosilylboranes 1–4 were verified by NMR spectroscopic measurements and in the case of [α-(dichloromethylsilyl)ethyl]dichloroborane-dimethylsulfide (4) the molecular structure was determined by single-crystal X-ray diffraction (L.M. Ruwisch, R. Riedel, U. Klingebiel, M. Noltemeyer, Z. Naturforsch., Teil B 54 (1999) 624). Following the Markovnikov rule, the first addition appears strictly regioselective in the α-position to silicon, producing one chiral methine group between silicon and dichloroborane in compound 4. The second addition of borane- or monochloroborane-dimethylsulfide at the vinyl groups of dichloromethylvinylsilane and trichlorovinylsilane also takes place in the α-position to silicon, forming a second chiral methine group. In the case of borane-dimethylsulfide the third addition occurs in the β-position (anti-Markovnikov) owing to steric hindrance to boron in tris[(dichloromethylsilyl)ethyl]borane (1). A stepwise substitution of chlorine bonded at boron in compounds 2 and 3 using hexamethyldisilazane produces bis[α-(dichloromethylsilyl)ethyl]boryl-trimethylsilylamine (5) and bis[α-(trichlorosilyl)ethyl]boryl-trimethylsilylamine (6), respectively, under release of chlorotrimethylsilane. The remaining trimethylsilylamine group in 6 can be replaced by further reaction with 3 forming tetrakis[α-(trichlorosilyl)ethyl]diborylamine (7). This reaction resembles a selective amino condensation at boron. In a similar condensation reaction of 4 with equivalent amounts of hexamethyldisilazane, tris[α-(dichloromethylsilyl)ethyl]borazine (8) can be obtained