TY  - JOUR
A1  - Ramler, Jaqueline
A1  - Fantuzzi, Felipe
A1  - Geist, Felix
A1  - Hanft, Anna
A1  - Braunschweig, Holger
A1  - Engels, Bernd
A1  - Lichtenberg, Crispin
T1  - The dimethylbismuth cation: entry into dative Bi-Bi bonding and unconventional methyl exchange
JF  - Angewandte Chemie International Edition
N2  - The dimethyl bismuth cation, [BiMe\(_2\)(SbF\(_6\))], has been isolated and characterized. Reaction with BiMe\(_3\) allows access to the first compound featuring Bi→Bi donor–acceptor bonding. In solution, dynamic behavior with methyl exchange via an unusual S\(_E\)2 mechanism is observed, underlining the unique properties of bismuth species as soft Lewis acids with the ability to undergo reversible Bi−C bond cleavage.
KW  - inorganic chemistry
KW  - methyl exchange
KW  - bismuth
KW  - cationic species
KW  - electrophilic substitution
KW  - Lewis acidity
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-256543
VL  - 60
ER  - 
TY  - JOUR
A1  - Ramler, Jacqueline
A1  - Krummenacher, Ivo
A1  - Lichtenberg, Crispin
T1  - Well‐Defined, Molecular Bismuth Compounds: Catalysts in Photochemically Induced Radical Dehydrocoupling Reactions
JF  - Chemistry – A European Journal
N2  - A series of diorgano(bismuth)chalcogenides, [Bi(di‐aryl)EPh], has been synthesised and fully characterised (E=S, Se, Te). These molecular bismuth complexes have been exploited in homogeneous photochemically‐induced radical catalysis, using the coupling of silanes with TEMPO as a model reaction (TEMPO=(tetramethyl‐piperidin‐1‐yl)‐oxyl). Their catalytic properties are complementary or superior to those of known catalysts for these coupling reactions. Catalytically competent intermediates of the reaction have been identified. Applied analytical techniques include NMR, UV/Vis, and EPR spectroscopy, mass spectrometry, single‐crystal X‐ray diffraction analysis, and (TD)‐DFT calculations.
KW  - bismuth
KW  - chalcogens
KW  - dehydrocoupling
KW  - photocatalysis
KW  - radical reactions
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-224577
VL  - 26
IS  - 64
SP  - 14551
EP  - 14555
ER  - 
TY  - JOUR
A1  - Hanft, Anna
A1  - Radacki, Krzysztof
A1  - Lichtenberg, Crispin
T1  - Cationic Bismuth Aminotroponiminates: Charge Controls Redox Properties
JF  - Chemistry – A European Journal
N2  - The behavior of the redox‐active aminotroponiminate (ATI) ligand in the coordination sphere of bismuth has been investigated in neutral and cationic compounds, [Bi(ATI)\(_{3}\)] and [Bi(ATI)\(_{2}\)L\(_{n}\)][A] (L=neutral ligand; n=0, 1; A=counteranion). Their coordination chemistry in solution and in the solid state has been analyzed through (variable‐temperature) NMR spectroscopy, line‐shape analysis, and single‐crystal X‐ray diffraction analyses, and their Lewis acidity has been evaluated by using the Gutmann–Beckett method (and modifications thereof). Cyclic voltammetry, in combination with DFT calculations, indicates that switching between ligand‐ and metal‐centered redox events is possible by altering the charge of the compounds from 0 in neutral species to +1 in cationic compounds. This adds important facets to the rich redox chemistry of ATIs and to the redox chemistry of bismuth compounds, which is, so far, largely unexplored.
KW  - aminotroponiminates
KW  - bismuth
KW  - cationic species
KW  - redox chemistry
KW  - redox-active ligands
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-225669
VL  - 27
IS  - 20
SP  - 6230
EP  - 6239
ER  - 
TY  - JOUR
A1  - Ramler, Jacqueline
A1  - Lichtenberg, Crispin
T1  - Molecular Bismuth Cations: Assessment of Soft Lewis Acidity
JF  - Chemistry – A European Journal
N2  - Three‐coordinate cationic bismuth compounds [Bi(diaryl)(EPMe\(_{3}\))][SbF\(_{6}\)] have been isolated and fully characterized (diaryl=[(C\(_{6}\)H\(_{4}\))\(_{2}\)C\(_{2}\)H\(_{1}\)]\(^{2-}\), E=S, Se). They represent rare examples of molecular complexes with Bi⋅⋅⋅EPR\(_{3}\) interactions (R=monoanionic substituent). The \(^{31}\)P NMR chemical shift of EPMe3 has been found to be sensitive to the formation of LA⋅⋅⋅EPMe\(_{3}\) Lewis acid/base interactions (LA=Lewis acid). This corresponds to a modification of the Gutmann–Beckett method and reveals information about the hardness/softness of the Lewis acid under investigation. A series of organobismuth compounds, bismuth halides, and cationic bismuth species have been investigated with this approach and compared to traditional group 13 and cationic group 14 Lewis acids. Especially cationic bismuth species have been shown to be potent soft Lewis acids that may prefer Lewis pair formation with a soft (S/Se‐based) rather than a hard (O/N‐based) donor. Analytical techniques applied in this work include (heteronuclear) NMR spectroscopy, single‐crystal X‐ray diffraction analysis, and DFT calculations.
KW  - bismuth
KW  - bonding analysis
KW  - cationic species
KW  - HSAB principle
KW  - Lewis acids
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-225808
VL  - 26
IS  - 45
SP  - 10250
EP  - 10258
ER  -