From Dead Ends to Catalyst Reservoirs: Bimetallic Reactivation of Homoleptic Nickel Pincer Complexes
Jun-Yang Ye1, Zheng-Feng Zhang2, Matthias Zeller3
1Department of Chemistry, National Central University, Taoyuan 32001, Taiwan.
Abstract:
Homoleptic nickel(II) pincer complexes are commonly regarded as thermodynamically stable off-cycle species that terminate catalytic activity. Here we show that such complexes can undergo clean conversion to monohalide LNiBr species through a bimetallic reactivation pathway. Treatment of a homoleptic Ni(II) pincer complex with NiBr2 generates a transient binuclear intermediate formed by association of the external metal salt with the pincer complex. UV-vis monitoring reveals the accumulation and subsequent decay of this intermediate during the transformation. Time-dependent DFT calculations identify characteristic metal-metal charge-transfer (MMCT) transitions that provide an electronic signature for the binuclear species and support the proposed structure. Notably, simple halide salts such as LiBr also promote conversion of the homoleptic complex to the monohalide LNiBr complex. These results provide insight into the reactivity of homoleptic nickel pincer complexes and illustrate how transient bimetallic interactions can mediate their transformation.
Related Concept Videos
Catalysis
Catalysis
Heterogeneous Catalysis
Reduction of Alkynes to cis-Alkenes: Catalytic Hydrogenation
Like alkenes, alkynes can be reduced to alkanes in the presence of transition metal catalysts such as Pt, Pd, or Ni. The reaction involves two sequential syn additions of hydrogen via a cis-alkene intermediate.
Reduction of Alkenes: Asymmetric Catalytic Hydrogenation
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...
Pericyclic Reactions: Introduction
Pericyclic reactions can be classified into three categories: electrocyclic reactions, cycloaddition reactions, and sigmatropic rearrangements. Electrocyclic reactions and sigmatropic rearrangements are...
![Mizoroki-Heck Cross-coupling Reactions Catalyzed by Dichloro{bis[1,1',1''-(phosphinetriyl)tripiperidine]}palladium Under Mild Reaction Conditions](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F51444.jpg&w=3840&q=50)

