Aromatic Methoxylation and Hydroxylation by Organometallic High-Valent Nickel Complexes

• Published in: Journal of the American Chemical Society 2015-06, Vol.137 (24), p.7604-7607
• Main Authors: Zhou, Wen, Schultz, Jason W, Rath, Nigam P, Mirica, Liviu M
• Format: Article
• Language: English
• Subjects: Aza Compounds - chemical synthesis; Aza Compounds - chemistry; Bridged-Ring Compounds - chemical synthesis; Bridged-Ring Compounds - chemistry; Coordination Complexes - chemical synthesis; Coordination Complexes - chemistry; Hydrocarbons, Aromatic - chemical synthesis; Hydrocarbons, Aromatic - chemistry; Hydroxylation; Ligands; Models, Molecular; Nickel - chemistry; Oxidation-Reduction
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/jacs.5b04082

Herein we report the synthesis and reactivity of several organometallic NiIII complexes stabilized by a modified tetradentate pyridinophane ligand containing one phenyl group. A room temperature stable dicationic NiIII–disolvento complex was also isolated, and the presence of two available cis coordination sites in this complex offers an opportunity to probe the C-heteroatom bond formation reactivity of high-valent Ni centers. Interestingly, the NiIII-dihydroxide and NiIII-dimethoxide species can be synthesized, and they undergo aryl methoxylation and hydroxylation that is favored by addition of oxidant, which also limits the β-hydride elimination side reaction. Overall, these results provide strong evidence for the involvement of high-valent organometallic Ni species, possibly both NiIII and NiIV species, in oxidatively induced C-heteroatom bond formation reactions.