The chemistry of the s- and p-block elements with 2,2′:6′,2′′-terpyridine ligands

The coordination chemistry of the 2,2′:6′,2′′-terpyridine (tpy) ligand is dominated by the transition-metal and rare-earth-metal ions. Some of these complexes have found prominent applications in the fields of light-to-energy conversion or pharmacy; moreover, tpy complexes represent important building blocks in metallo-supramolecular systems: Polymers, dendrimers, nanostructures, etc. Compared to the widespread use of transition-metal complexes, the related assemblies, based on main-group elements (s- or p-block), are less commonly studied. Nonetheless, some notable examples with promising photophysical or biomedical properties can also be found. For a long period of time, a systematic overview in this field of research has not been provided. This review aims to summarize and evaluate the available literature dealing with the chemistry of the main-group elements with tpy ligands. Beyond just providing a simple overview, we also intend to inspire intensified research in this often-disregarded field. Given that many main-group elements are cheap and earth-abundant, there might be plenty-of-room for innovation beyond the traditional use of “problematic” transition-metal ions.