An Isolable Mononuclear Palladium(I) Amido Complex
Jian Liu, Melissa M. Bollmeyer, Yujeong Kim, Dengmengfei Xiao, Samantha N. MacMillan, Qi Chen, Xuebing Leng, Sun Hee Kim, Lili Zhao, Kyle M. Lancaster, Liang Deng
Abstract
Mononuclear Pd(I) species are putative intermediates in Pd-catalyzed reactions, but our knowledge about them is limited due to difficulties in accessing them. Herein, we report the isolation of a Pd(I) amido complex, [(BINAP)Pd(NHArTrip)] (BINAP = 2,2′-bis(diphenylphosphino)-1,1′-binaphthalene, ArTrip = 2,6-bis(2′,4′,6′-triisopropylphenyl)phenyl), from the reaction of (BINAP)PdCl2 with LiNHArTrip. This Pd(I) amido species has been characterized by X-ray crystallography, electron paramagnetic resonance, and multiedge Pd X-ray absorption spectroscopy. Theoretical study revealed that, while the three-electron–two-center π-interaction between Pd and N in the Pd(I) complex imposes severe Pauli repulsion in its Pd–N bond, pronounced attractive interligand dispersion force aids its stabilization. In accord with its electronic features, reactions of homolytic Pd–N bond cleavage and deprotonation of primary amines are observed on the Pd(I) amido complex.