TY  - JOUR
A1  - Oberdorf, Kai
A1  - Hanft, Anna
A1  - Ramler, Jacqueline
A1  - Krummenacher, Ivo
A1  - Bickelhaupt, Matthias
A1  - Poater, Jordi
A1  - Lichtenberg, Crispin
T1  - Bismuth Amides Mediate Facile and Highly Selective Pn–Pn Radical‐Coupling Reactions (Pn=N, P, As)
JF  - Angewandte Chemie, International Edition
N2  - The controlled release of well‐defined radical species under mild conditions for subsequent use in selective reactions is an important and challenging task in synthetic chemistry. We show here that simple bismuth amide species [Bi(NAr\(_2\))\(_3\)] readily release aminyl radicals [NAr\(_2\)]. at ambient temperature in solution. These reactions yield the corresponding hydrazines, Ar\(_2\)N−NAr\(_2\), as a result of highly selective N−N coupling. The exploitation of facile homolytic Bi−Pn bond cleavage for Pn−Pn bond formation was extended to higher homologues of the pnictogens (Pn=N–As): homoleptic bismuth amides mediate the highly selective dehydrocoupling of HPnR\(_2\) to give R\(_2\)Pn−PnR\(_2\). Analyses by NMR and EPR spectroscopy, single‐crystal X‐ray diffraction, and DFT calculations reveal low Bi−N homolytic bond‐dissociation energies, suggest radical coupling in the coordination sphere of bismuth, and reveal electronic and steric parameters as effective tools to control these reactions.
KW  - bismuth amides
KW  - radical species
KW  - pnictogen coupling
KW  - aminyl radicals
KW  - diphosphanes
KW  - heavier pnictogens
KW  - radical coupling
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-236582
VL  - 60
IS  - 12
ER  - 
TY  - JOUR
A1  - Ramler, Jacqueline
A1  - Poater, Jordi
A1  - Hirsch, Florian
A1  - Ritschel, Benedikt
A1  - Fischer, Ingo
A1  - Bickelhaupt, F. Matthias
A1  - Lichtenberg, Crispin
T1  - Carbon monoxide insertion at a heavy p-block element: unprecedented formation of a cationic bismuth carbamoyl
JF  - Chemical Science
N2  - Major advances in the chemistry of 5th and 6th row heavy p-block element compounds have recently uncovered intriguing reactivity patterns towards small molecules such as H\(_2\), CO\(_2\), and ethylene. However, well-defined, homogeneous insertion reactions with carbon monoxide, one of the benchmark substrates in this field, have not been reported to date. We demonstrate here, that a cationic bismuth amide undergoes facile insertion of CO into the Bi–N bond under mild conditions. This approach grants direct access to the first cationic bismuth carbamoyl species. Its characterization by NMR, IR, and UV/vis spectroscopy, elemental analysis, single-crystal X-ray analysis, cyclic voltammetry, and DFT calculations revealed intriguing properties, such as a reversible electron transfer at the bismuth center and an absorption feature at 353 nm ascribed to a transition involving σ- and π-type orbitals of the bismuth-carbamoyl functionality. A combined experimental and theoretical approach provided insight into the mechanism of CO insertion. The substrate scope could be extended to isonitriles.
KW  - carbon monoxide
KW  - p-block element
Y1  - 2019
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-181627
VL  - 10
ER  -