Colour tuneability of heteroleptic iridium complexes through second-sphere coordination.

Novel H-bond-rich iridium(iii) complexes with different systems of cyclometalating ligands bearing the general formula [Ir(C^N)(N^N)] were synthesised, characterised and their photophysical properties determined. The incorporated guanidine moieties allow us to introduce a hydrogen-bonding array for the formation of self-assembled iridium-bound hydrogen-bonded systems. Through a series of experimental and computational studies we demonstrated the host-guest chemistry of these systems. These hydrogen-bonding interactions were shown to have significant impacts on chromaticity, quantum yields and lifetimes with emphasis on energy transfer studies based on this second-sphere coordination approach.