Reversible Modulation of the Electronic and Spatial Environment around Ni(0) Centers Bearing Multifunctional Carbene Ligands with Triarylaluminum.

Designing and modulating the electronic and spatial environments surrounding metal centers is a crucial issue in a wide range of chemistry fields that use organometallic compounds. Herein, we demonstrate a Lewis-acid-mediated reversible expansion, contraction, and transformation of the spatial environment surrounding nickel(0) centers that bear -phosphine oxide-substituted -heterocyclic carbenes (henceforth referred to as (S)PoxIms). Reaction between tetrahedral (-κ-,-(S)PoxIm)Ni(CO) and Al(CF) smoothly afforded heterobimetallic Ni/Al species such as trigonal-planar {κ--Ni(CO)}(μ--(S)PoxIm){κ--Al(CF)} via a complexation-induced rotation of the -phosphine oxide moieties, while the addition of 4-dimethylaminopyridine resulted in the quantitative regeneration of the former Ni complexes.

Room-Temperature Reversible Chemisorption of Carbon Monoxide on Nickel(0) Complexes.

Chemisorption on organometallic-based adsorbents is crucial for the controlled separation and long-term storage of gaseous molecules. The formation of covalent bonds between the metal centers in the adsorbents and the targeted gases affects the desorption efficiency, especially when the oxidation state of the metal is low. Herein, we report a pressure-responsive nickel(0)-based system that is able to reversibly chemisorb carbon monoxide (CO) at room temperature.

Axial Chirality around N-P Bonds Induced by Complexation between E(CF) (E = B, Al) and an -Phosphine Oxide-Substituted Imidazolinylidene: A Key Intermediate in the Catalytic Phosphinoylation of CO.

Complexation-induced axial chirality around an N-P bond occurs upon the predominant coordination of the -phosphinoyl group in the -phosphine oxide-substituted imidazolinylidene (SPoxIm) to B(CF). () and () atropisomers of (-SPoxIm)B(CF) were observed independently in the single-crystal lattice and the optimized gas-phase structure. Experimental and theoretical studies confirmed that this axial chirality arises from the restricted rotation around the N-P bond, caused by the steric repulsion between the C5-H atoms of the imidazolinylidene ring and the CF rings on the B(CF) unit.