Facile P−C/C−H Bond‐Cleavage Reactivity of Nickel Bis(diphosphine) Complexes

Abstract

Unusual cleavage of P-C and C-H bonds of the P2 N2 ligand, in heteroleptic [Ni(P2 N2 )(diphosphine)](2+) complexes under mild conditions, results in the formation of an iminium formyl nickelate featuring a C,P,P-tridentate coordination mode. The structures of both the heteroleptic [Ni(P2 N2 )(diphosphine)](2+) complexes and the resulting iminium formyl nickelate have been characterized by NMR spectroscopy and single-crystal X-ray diffraction analysis. Density functional theory (DFT) calculations were employed to investigate the mechanism of the P-C/C-H bond cleavage, which involves C-H bond cleavage, hydride rotation, Ni-C/P-H bond formation, and P-C bond cleavage.

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“…摩托车尾气净化催化剂的载体材料一般由Ce-Zr储 氧材料和Al 2 O 3 组成. 这是因为CeO 2 与ZrO 2 形成的固溶 体具有良好的储氧性能和可促进水-气转化反应等优点, 但抗老化和耐久性能较差 [9][10][11] , 而Al 2 O 3 具有高比表面 积、大孔体积和高抗老化等优异性能 [12,13] . Morikawa 等 [14] 研究发现, 用Al [5,19] .…”

Controlling P–C/C–H Bond Cleavage in Nickel Bis(diphosphine) Complexes: Reactivity Scope, Mechanism, and Computations

“…6,7 Deprotonation of α-C−H bonds by base in Ni complexes has been reported, particularly in the formation of pincer ligands. 8−10 We previously communicated 11 The difference in reactivities between [Ni(P 2 N 2 )-(diphosphine)] 2+ complexes bearing dmpbz and dmpe ligands suggests that the rigidity and steric effect of the ligand skeleton has an effect on the stability of [Ni(P 2 N 2 )(diphosphine)] 2+ complexes as well as P−C/C−H bond cleavage reactivity. In this paper, we report experimental and computational results on the influence of ligand rigidity and steric effects of both P 2 N 2 and diphosphine ligands on the coordination geometries of the active species and, consequently, the P−C/C−H bond cleavage reactivities.…”

“…Our previous studies by density functional theory (DFT) calculations on the mechanism of the P−C/C−H bond cleavage to form 3c and 3d established that the reactions involve four steps: C−H bond cleavage, isomerization of the hydride complex, Ni−C/P−H bond formation, and P−C bond cleavage (Figure 4). 11 To better understand the mechanism, we used computational methods to identify other possible mechanistic pathways for those four steps, as well as alternative coordination geometries of important intermediates (see the Supporting Information). We also examined the effect of some alternative functionals (see the Supporting Information and below).…”

“…We previously communicated the unusual cleavage of P–C and C–H bonds of the diphosphine P 2 N 2 ligand in heteroleptic [Ni­(P 2 N 2 )­(diphosphine)] 2+ complexes under mild conditions (dmpbz = 1,2-bis­(dimethylphosphino)­benzene; dmpe = 1,2-bis­(dimethylphosphino)­ethane). Nickel complexes featuring a C,P,P -tridentate coordination mode were isolated and characterized as P–C/C–H bond cleavage products.…”

“…Optimized geometries for some species are shown in FigureS8. The values in blue were calculated at the Def2-TZVP/BS1 level using the TPSS functional and were included in our prior communication 11.…”