Colour Tunability of Heteroleptic Ir(III) 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)2(N^N)] were synthesized, characterized and their photophysical properties measured. The incorporated guanidine moieties allow us to introduce a hydrogen-bonding array for the formation of self-assembled iridium hydrogen-bonded systems. Through a series of UV-Vis binding studies we demonstrated the host-guest chemistry of these systems display high levels of colour tuneability. These hydrogen-bond interactions were also shown to have significant impacts on chromaticity, quantum yields and lifetimes with emphasis on energy transfer studies based on this second-sphere coordination approach.