The One-Electron Oxidation of an Azazirconacyclobutene in the Presence of B(C₆F₅)₃

Single Electron Transfer to Diazomethane–Borane Adducts Prompts C−H Bond Activations

“…Collectively, the identification of 1 and 2 is consistent with two possible reaction mechanisms involving single electron transfer from a Co II center to either B(C 6 F 5 ) 3 or the diazomethane adduct of the borane, (Ph 2 CN 2 )B(C 6 F 5 ) 3 . It is noteworthy that although C−H activation by the radical [B(C 6 F 5 ) 3 )] .− , is expected to give the anion [HB(C 6 F 5 ) 3 ] − , independent combination of diazomethane with [HB(C 6 F 5 ) 3 ] − showed no reaction. This supports the view that compound 1 is formed through hydrogen atom abstraction from Cp* 2 Co by the transient diazomethane‐borane adduct radical anion [Ph 2 CN 2 B(C 6 F 5 ) 3 ] .− (Scheme ), consistent with the overall reaction ratio of diazomethane:Cp* 2 Co:B(C 6 F 5 ) 3 of 1:2:2.…”

Bildung eines zwitterionischen Einkomponentenkatalysators für die Ethenpolymerisation auf Basis von Butadiennickelkomplexen: ein alternativer Aktivierungsweg bei homogenen Ziegler-Natta-Katalysatoren später Übergangsmetalle

“…Die Chemie dieser Systeme könnte im Hinblick auf einige neue Befunde zu Ziegler‐Natta‐Katalysatoren auf Basis später Übergangsmetalle von besonderer Bedeutung sein. Es wurde beobachtet,7, 8 dass die Bis(imin)halogencobalt( II )‐Chelatkomplexe 4 bei der Behandlung mit MAO nicht primär alkyliert, sondern zu den Co I ‐Komplexen 5 reduziert werden (Schema ) 9, 10. Die nachfolgende Alkylierung von 5 und Abstraktion eines Alkylanions muss dann zu einem Kation führen, das keinen σ‐gebundenen Alkylliganden enthält und als direkte Vorstufe des aktiven Katalysators anzusehen ist, obwohl ihm die notwendige Metall‐Kohlenstoff‐σ‐Bindung fehlt 11.…”

Aryldiazonium Salts as Nitrogen‐Based Lewis Acids: Facile Synthesis of Tuneable Azophosphonium Salts

“…[25] Subsequent radical coupling with the concomitantly formed phosphine radical cation (R 3 PC + )presents an alternative pathway to afford these readily tuneable azophosphonium salts.A sN -based Lewis bases,such as arylamines,are known to undergo one-electron oxidation by Lewis acids to generate the corresponding radical cations, [26] we also included triphenylamine and triisopropylamine (tBu 3 Nisstill elusive) [27] in our mechanistic study. [25] Subsequent radical coupling with the concomitantly formed phosphine radical cation (R 3 PC + )presents an alternative pathway to afford these readily tuneable azophosphonium salts.A sN -based Lewis bases,such as arylamines,are known to undergo one-electron oxidation by Lewis acids to generate the corresponding radical cations, [26] we also included triphenylamine and triisopropylamine (tBu 3 Nisstill elusive) [27] in our mechanistic study.…”