TY  - JOUR
A1  - Braunschweig, Holger
A1  - Ewing, William C.
A1  - Ghosh, Sundargopal
A1  - Kramer, Thomas
A1  - Mattock, James D.
A1  - Östreicher, Sebastian
A1  - Vargas, Alfredo
A1  - Werner, Christine
T1  - Trimetallaborides as starting points for the syntheses of large metal-rich molecular borides and clusters
JF  - Chemical Science
N2  - Treatment of an anionic dimanganaborylene complex ([{Cp(CO)\(_2\)Mn}\(_2\)B]\(^-\)) with coinage metal cations stabilized by a very weakly coordinating Lewis base (SMe\(_2\)) led to the coordination of the incoming metal and subsequent displacement of dimethylsulfide in the formation of hexametalladiborides featuring planar four-membered M\(_2\)B\(_2\) cores (M = Cu, Au) comparable to transition metal clusters constructed around four-membered rings composed solely of coinage metals. The analogies between compounds consisting of B\(_2\)M\(_2\) units and M\(_4\) (M = Cu, Au) units speak to the often overlooked metalloid nature of boron. Treatment of one of these compounds (M = Cu) with a Lewis-basic metal fragment (Pt(PCy\(_3\))\(_2\)) led to the formation of a tetrametallaboride featuring two manganese, one copper and one platinum atom, all bound to boron in a geometry not yet seen for this kind of compound. Computational examination suggests that this geometry is the result of d\(^{10}\)-d\(^{10}\) dispersion interactions between the copper and platinum fragments.
KW  - anionic dimetalloborylene complexes
KW  - trimetallaborides
KW  - tetrametallaborides
KW  - Boron
KW  - metallaboranes
KW  - crystal structure
KW  - metal borylene complexes
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-191511
VL  - 7
IS  - 1
ER  - 
TY  - THES
A1  - Östreicher, Sebastian
T1  - Synthese und Eigenschaften neuartiger Di-, Tri- und Tetrametalloboridokomplexe
T1  - Synthesis and Characterisation of Novel Di-, Tri-, and Tetrametalloborido Complexes
N2  - Unter Ausnutzung der Reaktivität von Borylanionen wurden neuartige Übergangsmetallboridokomplexe synthetisiert, bei denen ein "nacktes" Boratom als Ligand für bis zu vier Übergangsmetalle vorliegt. Strukturelle und bindungstheoretische Eigenschaften der Boridokomplexe wurden mit gängigen metallorganischen Analysemethoden sowie mit DFT-Methoden untersucht. Dabei zeigte sich, dass die erhaltenen Tetrametalloboridokomplexe eine planare Koordinationsgeometrie um das Borzentrum aufweisen und damit ein Äquivalent zu anti van't Hoff/Le Bel-Verbindungen des Kohlenstoffs darstellen.
N2  - Exploiting the reactivity of boryl anions, novel transition metal borido complexes were synthesised. Borido complexes feature a "naked" boron atom that serves as a ligand for up to four metals. Structucal characterisation of the boridokomplexes was carried out by means of common analytical methods as well as DFT-calculations. Tetrametalloborido complexes showed a remarkably planar geometry around the boron center and can therefore be considered as anti van't Hoff/Le Bel compounds.
KW  - Übergangsmetall
KW  - Mehrkernige Komplexe
KW  - Bor-Übergangsmetallverbindungen
KW  - Boridokomplexe
KW  - Borylanionen
KW  - anti-van't Hoff/Le Bel Verbinfungen
KW  - transition metal boron complexes
KW  - borido complexes
KW  - boryl anions
KW  - anti van't Hoff/Le Bel-compounds
Y1  - 2012
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-73943
ER  - 
TY  - JOUR
A1  - Scheidel, Sebastian
A1  - Östreicher, Laurina
A1  - Mark, Isabelle
A1  - Pöppler, Ann-Christin
T1  - You cannot fight the pressure: Structural rearrangements of active pharmaceutical ingredients under magic angle spinning
JF  - Magnetic Resonance in Chemistry
N2  - Although solid-state nuclear magnetic resonance (NMR) is a versatile analytical tool to study polymorphs and phase transitions of pharmaceutical molecules and products, this work summarizes examples of spontaneous and unexpected (and unwanted) structural rearrangements and phase transitions (amorphous-to-crystalline and crystalline-to-crystalline) under magic angle spinning (MAS) conditions, some of them clearly being due to the pressure experienced by the samples. It is widely known that such changes can often be detected by X-ray powder diffraction (XRPD); here, the capability of solid-state NMR experiments with a special focus on \(^{1}\)H-\(^{13}\)C frequency-switched Lee–Goldburg heteronuclear correlation (FSLG HETCOR)/MAS NMR experiments to detect even subtle changes on a molecular level not observable by conventional 1D NMR experiments or XRPD is presented. Furthermore, it is shown that a polymorphic impurity combined with MAS can induce a crystalline-to-crystalline phase transition. This showcases that solid-state NMR is not always noninvasive and such changes upon MAS should be considered in particular when compounds are studied over longer time spans.
KW  - \(^{1}\)H-\(^{13}\)C HETCOR
KW  - API
KW  - structural changes
KW  - XRPD
KW  - solid-state NMR
KW  - MAS
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-318838
VL  - 60
IS  - 6
SP  - 572
EP  - 582
ER  -