Mechanistic Insight into the Hydrogen Activation by Frustrated Lewis Pairs

Abstract

The combination of a Lewis acidLewis acid (LA) and a Lewis baseLewis base (LB) in such a way that they are prevented from forming a classical LA–LB adduct by means of steric hindrance or thermal hindrance is called a Frustrated Lewis PairFrustrated Lewis pair (FLP) (FLP). FLPs have been shown to function as metal-free catalysts for small molecule activation and conversion. In this chapter, we review theoretical results from combined quantum mechanical calculations and first-principles (DFT) Density functional theory (DFT) molecular dynamics/metadynamicsMetadynamics simulations with the aim of understanding the mechanistic aspects of FLPFrustrated Lewis pair (FLP) reactivity. Our results are contextualized with the recently published work from other researchers. The mechanisms of H2 activation by both inter- and intramolecularIntramolecular FLPs are examined and the impact of water on FLPFrustrated Lewis pair (FLP) reactivity is discussed. Furthermore, the possibility of alternative mechanisms of H2 activation by activated carbonyl carbon is presented. Carbonyl carbon is activated (polarized) by complexation of the C = O group to a Lewis/Brønsted acid or formation of an H-bond with an H-bond donor in solution. Finally, an overview of applications of Lewis pair-functionalized metal–organic frameworks (MOFs)Metal organic framework (MOF) for H2 activation is given.