Redox and photochemical/photophysical properties of compounds containing mesoionic carbene ligands

Abstract

The 1,2,3-triazolylidene type mesoionic carbenes (MICs), which are a subclass of N-heterocyclic carbenes, have received immense popularity over the past decade from a fundamental point of view as well as for their catalytic applications and beyond. The key factors for this popularity are their strong donor properties and their modular synthesis. Although these MICs have mostly been used as ligands with transition metals, the past few years have also witnessed their fascinating chemistry with main group elements. In this chapter we present an overview of the recent developments on this class of compounds, which include, amongst others: (i) redox-activity based directly on MICs, (ii) redox-activity influenced by MICs, (iii) photochemistry/photophysics of 4d and 5d metal complexes and, (iv) photochemistry/photophysics of 3d metal complexes and of main group compounds. We describe the state of the art of compounds containing MICs in these fields, and demonstrate a perspective for future research in these areas.