Electronic structure and reactivity of nickel(i) pincer complexes: their aerobic transformation to peroxo species and site selective C–H oxygenation

Abstract

The dinuclear nickel peroxo complexes undergo autoxidation giving a cyclic alkoxo or peroxo complex in the presence or absence of O2, respectively.

A Biomass‐Derived Non‐Noble Cobalt Catalyst for Selective Hydrodehalogenation of Alkyl and (Hetero)Aryl Halides

“…[2,3] Additionally,s tereoselective hydrodehalogenation of prochiral gem-dihalo-organic compounds affords chiral halo-organic compounds. [4] Hydrodehalogenation reactions have been performed with various methods,s uch as metal-halogen exchange, [2, 5] metal-mediated reduction, [2,6] photochemical reduction, [7] and reductive radical dehalogenation.…”

“…[8] Some of these reactions are marred by the use of toxic and explosive reagents, production of stoichiometric metal waste,poor selectivity,and low functional-group tolerance.Nevertheless,there has been an intense research interest in developing more efficient and reliable transition-metal-catalyzed hydrodehalogenation processes (mostly involving,Pd, [9] Rh, [10] Ru, [11] Ni, [4,12] and Fe [13] ) using Grignard reagents, [12c,13] alcohol and base, [9a, 10c, 11a,c] hydrides, [4,9b,c, 12b,d,14] formic acid [9h] or its salt, [9e] hydrazine, [9d] and molecular hydrogen. [9c,f,g,10a,b, 11b,12a] Obviously,f rom an ecological perspective,t he later reagent is considered to be the most efficient, clean, and atom-economical reductant.…”

“…[2,3] Additionally,s tereoselective hydrodehalogenation of prochiral gem-dihalo-organic compounds affords chiral halo-organic compounds. [4] Hydrodehalogenation reactions have been performed with various methods,s uch as metal-halogen exchange, [2,5] metal-mediated reduction, [2,6] photochemical reduction, [7] and reductive radical dehalogenation. [8] Some of these reactions are marred by the use of toxic and explosive reagents, production of stoichiometric metal waste,poor selectivity,and low functional-group tolerance.Nevertheless,there has been an intense research interest in developing more efficient and reliable transition-metal-catalyzed hydrodehalogenation processes (mostly involving,Pd, [9] Rh, [10] Ru, [11] Ni, [4,12] and Fe [13] ) using Grignard reagents, [12c,13] alcohol and base, [9a, 10c, 11a,c] hydrides, [4,9b,c, 12b,d,14] formic acid [9h] or its salt, [9e] hydrazine, [9d] and molecular hydrogen.…”

Ein biomimetischer Nickelkomplex mit einem reduzierten, durch Formiatdeprotonierung erzeugten CO2‐Liganden und sein Verhalten gegenüber CO2

“…Die Reaktion von L t Bu NiBr (L t Bu =[HC(C( t Bu)NC 6 H 3 ( i Pr) 2 ) 2 ] − ) mit NBu 4 OOCH liefert L t Bu NiOOCH ( 1 in Schema ) in guter Ausbeute, und die Festkörperstruktur gab ein quadratisch‐planar koordiniertes Nickelzentrum mit einem η 2 ‐gebundenen Formiat zu erkennen (Abbildung ). Dies ist ungewöhnlich für Nickelformiat‐Komplexe, die typischerweise eine η 1 ‐Koordination bevorzugen, aber in diesem speziellen Fall verständlich, wenn man die niedrige Koordinationszahl in 1 bedenkt. Das 1 H‐NMR‐Spektrum von 1 in C 6 D 6 zeigt Signale zwischen δ =7.07 und 0.98 ppm mit einem für eine C 2 v ‐symmetrische quadratisch‐planare Koordination des Nickelzentrums erwarteten Muster.…”

An In‐Depth Look at the Reactivity of Non‐Redox‐Metal Alkylperoxides

“…[31,41] However,g iven the progress that has been made in synthesis of both T MOOR and NR MOOR species,v ery little is known about the nature of their further transformations.T hermal decomposition of T MOOR species usually leads to metal alkoxide,h ydroxide,o ro xo compounds,a nd these transformations are occasionally accompanied by the supporting ligand C À Ha ctivation. [10,11,[42][43][44][45][46][47][48] Thea nalogous diversity of products has also been encountered during the controlled oxygenation of organozincs,w hich convincingly exemplified hitherto overlooked decomposition pathways of (L)ZnOOR species likely mediated by the OÀOb ond homolysis. [49][50][51][52] Moreover,the formation of metal hydroxides was exceptionally observed in the case of reactions involving aluminum bdiketiminates with TBHP or O 2 .…”