Chapter 23 - Application of frustrated Lewis pairs in small molecule activation and associated transformations

Abstract

The chemistry of frustrated Lewis pair (FLP) is enriching rapidly. The present chapter provides a survey of several experimental work on FLPs and mechanistic insights into their reactivity from electronic structure theory calculation. The results of quantum chemical calculations in understanding the mechanism of H2 activation is clearly demonstrated in this chapter, which would help in designing more effective catalysts of H2 activation. NO, CO, CO2, SO2, N2O, alkenes, alkynes, etc., small molecules become activated by cooperative action of both the Lewis centers of FLP as demonstrated by different computational study. Nucleus-independent chemical shift (NICS) analysis illustrates the role of aromaticity in decreasing the activation barrier for the activation of H2 and other small molecules by FLP. Hydrogenation of imine, nitrile, enamine, aziridine, aldehyde, ketone, alkene, alkyne catalyzed by FLP and the mechanisms of hydrogenation process are discussed here. The term boron-ligand cooperation (BLC) in analogy to the metal ligand cooperation (MLC) has been suggested in order to demonstrate a specific reactivity of some FLPs in the activation of chemical bonds. FLPs containing Al(C6F5)3 as Lewis acid (LA) can polymerize a monomer molecule, which is described in the last section of this chapter.