Year: 2026
Type: article
Abstract: High Resolution Image Download MS PowerPoint Slide Exposure of cyclohexane solutions of ( iPr DI)Co(η 3 -C 3 H 5 ) ( iPr DI = [2,6- i Pr 2 -C 6 H 3 N = C(CH 3 )] 2 ) to a H 2 atmosphere in the presence of excess arene resulted in the formation of a transient cobalt hydride [( iPr DI)Co–H], which formed the corresponding cobalt cyclohexadienyl compounds arising from arene insertion. Competing formation of a dinuclear bridging dicobalt dihydride, [( iPr DI)Co(H)] 2, was identified and contributed to the observed modest yields. The dimeric structure of [( iPr DI)Co(H)] 2 was confirmed in the solid state by X-ray diffraction, and the presence of two bridging hydride ligands was quantified by a Toepler pump experiment. The putative monomeric [( iPr DI)Co–H] favored insertion at the ortho and meta positions of representative monosubstituted arenes. Reducing the size of the 2,6-aryl substituents on the α-diimine ligand from i Pr to Me enabled the synthesis of [( Mes DI)Co(η 3 -C 3 H 5 )(μ-N 2 )] 2 ( Mes DI = 2,4,6-Me 3 -C 6 H 3 N = C(CH 3 )] 2 ), which was characterized by X-ray diffraction. Exposure to H 2 generated the putative [( Mes DI)Co–H] whose reduced steric profile supported insertion of more sterically demanding arenes such as tert -butylbenzene and xylenes, with ortho- and meta- substituent site selectivity. Overall, the ligand donacity conferred by the α-diimine ligand promoted unique reactivity and selectivity on the process of arene insertion into a cobalt-hydride bond, as compared to reported bis(phosphine) cobalt complexes.
Source: Organometallics
Institution: Princeton University
Language: English
Subfield: Organic Chemistry
Field: Chemistry
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,500
OpenAlex ID: W7150759373