752 research outputs found
Ducks in space groups! Students grasping 3D arrangement of symmetry elements with hands-on models
No full textTangible symmetry elements and space‐group models to guide from molecular to solid‐state composition
No full textThe ability to imagine symmetry and the spatial arrangement of atoms and molecules is crucial in chemistry in general. Teaching and understanding crystallography and the composition of the solid state therefore require understanding of symmetry elements and their relationships. To foster the student's spatial imagination, models representing a range of concepts from individual rotation axes to complete space groups have been designed and built. These models are robust and large enough to be presented and operated in a lecture hall, and they enable students to translate conventional 2D notations into 3D objects and vice versa. Tackling them hands‐on means understanding them.Large and robust models of the most abundant space groups and symmetry elements are presented as an aid to visualization. In this way, space‐group symmetry can be introduced to any audience in a readily understandable manner. imag
An investigation of Solid‐State Emission of Halogenated Diphenyl Phosphanyl Anthracenes
No full textIn today's world, the development and research of optoelectronic materials and devices based on solid-state luminescence is essential. Due to their versatile application possibilities, e.g. as light-emitting diodes or lasers, they are already indispensable. This work presents three halogenated anthracene derivatives [9-PPh2-10-X-(C14H8)] and their respective photoluminescent behavior in solution and in the solid state. The formation of halogen–π interactions in the solid state leads to unanticipated luminescence properties for the chlorinated species, resulting in a strong bathochromic shift, green fluorescence and a longer lifetime. In contrast, the other two derivatives, which in turn form only weak π–π interactions due to a small overlap of the anthracene rings, barely change their luminescence behavior in the solid state. By employing additional charge density studies, the structure–property correlation is also investigated. In particular, focus is given to halogen bonding and halogen–π interactions and their influence on photophysical properties of the studied compounds. Through the new knowledge gained, this study will help in the future development and selective application of the photophysical properties of solid-state luminescent materials.PL‐GRID infrastructur
Introducing NacNac-Like Bis(4,6-isopropylbenzoxazol-2-yl)methanide in s-Block Metal Coordination
No full textIndium K α radiation from a MetalJet X-ray source: the long way to a successful charge-density investigation
No full textThe MetalJet X-ray source provides indium K α radiation with a wavelength even shorter than Ag radiation. This paper reports on problematic spectral impurities and presents possible countermeasures so that collection of data with excellent quality up to a high resolution is possible. It is demonstrated that these data can be used in the refinement of a multipole model, the results of which are used for a topological analysis to assess the bonding situation in a sulfur ylide compound.Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/50110000165
Indium K α radiation from a MetalJet X-ray source: comparison of the Eiger2 CdTe and Photon III detectors
No full textThe MetalJet source makes available new K α radiation wavelengths for use in X-ray diffraction experiments. The purpose of this paper is to demonstrate the application of indium K α radiation in independent-atom model refinement, as well as approaches using aspherical atomic form factors. The results vary greatly depending on the detector employed, as the energy cut-off of the Eiger2 CdTe provides a solution to a unique energy contamination problem of the MetalJet In radiation, which the Photon III detector cannot provide.Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/50110000165
Amidinate based indium( iii ) monohalides and β-diketiminate stabilized In( ii )–In( ii ) bond: synthesis, crystal structure, and computational study
No full textAmmonia activation using a heteroleptic stannylene and lithium stannylenoid formation facilitated by hemilabile iminophosphorane-based ligands
Get PDFHeteroleptic stannylenes with iminophosphorane and terphenyl ligands were synthesized and studied for NH 3 activation. Synthetic and computational analyses revealed a redox-neutral activation path and identified a novel lithium stannylenoid byproduct.Heteroleptic stannylenes, featuring pendant hemilabile iminophosphorane functionalities and kinetically stabilizing terphenyl ligands, were synthesized straightforwardly through formal C–H activation. Subsequently, they were investigated for their ability to activate ammonia through N–H bond scission. By combining synthetic modifications of the ancillary ligand framework and computational analyses, detailed insights into the mechanism of NH 3 activation by these systems were obtained, highlighting an activation pathway at tin without a change in oxidation state. Additionally, an observed by-product during these studies underscores the non-innocence of a lithium salt in the synthesis of the stannylene starting materials, providing access to a novel lithium stannylenoid.Heteroleptic stannylenes with iminophosphorane and terphenyl ligands were synthesized and studied for NH 3 activation. Synthetic and computational analyses revealed a redox-neutral activation path and identified a novel lithium stannylenoid byproduct.Heteroleptic stannylenes, featuring pendant hemilabile iminophosphorane functionalities and kinetically stabilizing terphenyl ligands, were synthesized straightforwardly through formal C–H activation. Subsequently, they were investigated for their ability to activate ammonia through N–H bond scission. By combining synthetic modifications of the ancillary ligand framework and computational analyses, detailed insights into the mechanism of NH 3 activation by these systems were obtained, highlighting an activation pathway at tin without a change in oxidation state. Additionally, an observed by-product during these studies underscores the non-innocence of a lithium salt in the synthesis of the stannylene starting materials, providing access to a novel lithium stannylenoid.Verband der Chemischen Industrie https://doi.org/10.13039/100007215Alexander von Humboldt-Stiftung https://doi.org/10.13039/100005156Georg-August-Universität Göttingen https://doi.org/10.13039/50110000338
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