Noncovalent CH–π and π–π Interactions in Phosphoramidite Palladium(II) Complexes with Strong Conformational Preference

Abstract

The weak noncovalent interactions and flexibility of ligands play ak ey role in enantioselective metal-catalyzed reactions.I nt ransition metal complexes and their catalytic applications,the experimental assessment and the design of key interactions is as difficult as the prediction of the enantioselectivities,e specially for flexible,p rivileged ligands such as chiral phosphoramidites.T herefore,t he interligand interactions in cis-Pd II L 2 Cl 2 phosphoramidite complexes were investigated by NMR spectroscopyand computations.W ewere able to induce as trong conformational preference by breaking the symmetry of the C 2 -symmetric side chain of one of the ligands, and shift the equilibrium between hetero-and homocomplexes towards heterocomplexes because of interligand interactions in the cis-complexes.T he modulation of aryl substituents was exploited, along with the solvent effect. The combined CH-p and p-p interactions reveal design patterns for binding and folding of chiral ligands and catalysts.

A Critical Review of the Modelling Tools for the Reactive Transport of Organic Contaminants

“…Sorption by electrostatic interaction depends on the pH of the solution and the point of zero charge (PZC) of the sorbent [199]. Modelling studies have shown that π-π interactions and H-bonding interactions play an important role in the sorption of PAHs (polycyclic aromatic hydrocarbons) [200][201][202][203]. π-π interactions are weak non-covalent interactions that influence the chemical structure by providing significant stabilisation and strengthening of the bonds.…”