1807-51-8Relevant academic research and scientific papers
Bismuth Amides Mediate Facile and Highly Selective Pn–Pn Radical-Coupling Reactions (Pn=N, P, As)
Oberdorf, Kai,Hanft, Anna,Ramler, Jacqueline,Krummenacher, Ivo,Bickelhaupt, F. Matthias,Poater, Jordi,Lichtenberg, Crispin
supporting information, p. 6441 - 6445 (2021/02/01)
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(NAr2)3] readily release aminyl radicals [NAr2]. at ambient temperature in solution. These reactions yield the corresponding hydrazines, Ar2N?NAr2, 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 HPnR2 to give R2Pn?PnR2. 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.
N,N-di(4-halophenyl)nitrenium ions: Nucleophilic trapping, aromatic substitution, and hydrogen atom transfer
Thomas, Selina I.,Falvey, Daniel E.
, p. 4626 - 4634 (2008/02/07)
(Figure Presented) The reactive intermediates N,N-di(4-chlorophenyl) nitrenium ion and N,N-di(4-bromophenyl)nitrenium ion were generated through photolysis of the corresponding N-amino(2,4,6,-collidinium) ions. The behavior of these diarylnitrenium ions was characterized by laser flash photolysis, analysis of the stable photoproducts, and ab initio calculations with density functional theory. The latter predict these species to have singlet ground states. The halogenated diarylnitrenium ions are significantly longer lived than the unsubstituted diphenylnitrenium ion. Specifically, cyclization to form carbazole derivatives occurs negligibly, if at all, with the halogenated derivatives. They do, however, carry out most of the characteristic reactions of singlet arylnitrenium ions, including combining with nucleophiles on the aryl rings, adding to arenes, and accepting electrons from readily oxidized traps. Interestingly these species also abstract H atoms from 1,4-cyclohexadiene and various phenol derivatives. The implication of the latter process in relation to the computed singlet-triplet energy gaps of ca. -12.5 kcal/mol is discussed.
