The aim of this work is to understand  the factors that determine the activity and selectivity of transition-metal catalysts in oxidative-addition steps that occur in bond activation and cross-coupling reactions. We studied the effect of varying the metal M along the d10 metals of groups 9, 10 and 11, in combination with varying the number as well as the type of ligands, using relativistic density functional theory (DFT)  and the activation strain model (ASM) .
Figure 1. Schematic illustration of concepts presented in this lecture.
Three concepts for tuning a catalyst’s activity emerge: (i) d-regime catalysts; (ii) s-regime catalysts; and (iii) bite-angle flexibility (see Figure 1, left). These concepts explain why the effect of one and the same ligand on a catalyst’s activity can be completely different, even opposite, for catalysts from different electronic regimes. Furthermore, I will point out why not the bite angle itself, but its flexibility is decisive for the catalyst’s activity. Finally, I show how the latter is influenced not only by steric repulsion but also by what we designate “steric attraction” (see Figure 1, right).
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