Highly Luminescent Mixed-Metal Pt(II)/Ir(III) Complexes: Bis-Cyclometalation of 4,6-Diphenylpyrimidine As a Versatile Route to Rigid Multimetallic Assemblies

Multimetallic complexes comprising cyclometalated platinum(II) and iridium(III) centers have been prepared by a strategy in which 4,6-diphenylpyrimidine is used as a bis-NC-coordinating ligand. The two NC sites can be metalated either simultaneously or in a stepwise manner, allowing easy access to homo- and heterometallic assemblies, which are highly luminescent. The radiative rate constants are increased, and the excited state energies are lowered compared to monometallic analogues, and the trends are interpreted with the aid of electrochemical measurements and density functional theory.