Structural, Spectroscopic, and Theoretical Elucidation of a Redox-Active Pincer-Type Ancillary Applied in Catalysis

Abstract

Pincer-type ligands are believed to be very robust scaffolds that can support multifarious functionalities as well as highly reactive metal motifs applied in organometallic chemistry, especially in the realm of catalysis. In this paper, we describe the redox and, therefore, noninnocent behavior of a PNP (PNP- = N[2-P(CHMe2)2-4-methylphenyl]2) pincer ancillary bound to nickel. A combination of structural, spectroscopic, and theoretical techniques suggests that this type of framework can house an electron hole when coordinated to Ni(II).

Bimetallic Oxidative Addition in Nickel-Catalyzed Alkyl–Aryl Kumada Coupling Reactions

“…PBE0-dDsC computations used the TZ2P slater-type orbital basis set in ADF. 42,43 Solvation corrections, also computed at the PBE0-dDsC/TZ2P//M06/def2-SVP level, were determined in THF solvent using Klamt's Continuum Solvation The alternative escape-rebound pathway commences with structure E1, which, based analysis of the computed spin density is a doublet Ni(III) halide (Br) complex and not a Ni(II) ligand cation complex 45,46 owing to majority of the spin density being located on the nickel center (see SI Figure S10 Based on these findings, the bimetallic oxidative addition pathway is strongly preferred over the escape-rebound pathway based on its superior energetic profile (notably the barrierless association of the alkyl radical and small TS associated with reductive elimination of the alkyl-aryl product). In principle, these two pathways are interconnected by a reaction in which B1 abstracts a bromine atom from .…”

Neutral Tridentate PNP Ligands and Their Hybrid Analogues: Versatile Non‐Innocent Scaffolds for Homogeneous Catalysis

“…[81] It was demonstrated that ligand 4 can behave as a redox-based non-innocent ligand under certain reaction conditions.…”

Trends in Covalency for d- and f-Element Metallocene Dichlorides Identified Using Chlorine K-Edge X-ray Absorption Spectroscopy and Time-Dependent Density Functional Theory

“…30 . 42 This technique probes bound state transitions occur on low energy side the ligand K-edge, and involves excitation of ligand Is electrons into molecular orbitals of primarily metal charactt?r35 that also contain some ligand p character, due to covalent mixing. The intensity of the pre-edge transition is a direct measure of the ligand p orbital 3 Cpstr Full JACS_SAK Feb 152009 contribution to the primarily metal-based antibonding orbital.…”