Catalytic nitrene transfer by a zirconium(iv) redox-active ligand complex

A Redox‐Active Ligand as a Reservoir for Protons and Electrons: O2 Reduction at Zirconium(IV)

“…Thus, in the reaction the ligands serve as an electron reservoir to help effect multielectron reactivity at a non-redox-active metal. Similar reactions with redox-active ligands have been elucidated for oxidative addition, [12][13][14] reductive elimination, [15] and nitrene trans- fer [16,17] reactivity at d 0 complexes of the group 4 and 5 metals. In this report, we extend this approach beyond the utilization of the ligands as just electron reservoirs to develop a redox-active ligand that serves as both an electron and proton reservoir for O 2 reduction.…”

Nickel(ii) radical complexes of thiosemicarbazone ligands appended by salicylidene, aminophenol and aminothiophenol moieties

“…[5][6][7][8][9][10][11]23 The phenoxyl/phenolate redox couple is unexpectedly irreversible, in contrast with what is commonly observed in Ni(II) salen complexes involving sterically hindered phenolates. 23 This behaviour most likely results the higher lability of the proton of the Cβ (C7 in Fig.…”

Titanium redox catalysis: insights and applications of an earth-abundant base metal

“…36 This reaction is similar to a strategy employed by Heyduk for Zr-catalyzed isocyanide imination. 37 Unlike the other reactions presented herein, this reaction hinges on the redox noninnocent behavior of the tetradentate (dadi) ancillary ligand, which cycles between a (dadi) 4− and (dadi) 2− state upon oxidation, instead of metal-based redox (Figure 9b). An important feature of this catalytic system is that the redox changes of the (dadi) ligand prevent strong binding of CO, which may partially explain why this reaction can be run at significantly lower temperature than the alkyne oxidative amination reactions.…”