Luminescent Ir(III) complexes with deprotonated 1-methyl-2-(2′-pyridyl)pyridinium ligand and 1,10-phenanthroline derivatives

Abstract

A series of novel cationic [Ir(C^N)2(N^N)]3+ complexes bearing deprotonated 1-methyl-2-(2′-pyridyl)pyridinium (C^N) as cyclometalating ligand and 1,10-phenanthroline derivatives (N^N) as ancillary ligands have been prepared in the form of PF6− salts and identified by means of 1H and 31P NMR spectroscopy. Their luminescence properties have been studied in acetonitrile solutions at room temperature and in CH3OH/C2H5OH 1:1 glasses at 77 K. Depending on the α-diimine ligand coordinated, the room temperature values of emission wavelength λem, quantum yield ϕem and lifetime τem vary in the range of 535–630 nm, 0.12–0.60, and 0.06–840 μs, respectively. The complexes display the changes in the nature of the emissive states, their emission occurs either from the excited triplet states (3*C^N or 3*N^N) or from the excited singlet state (1*N^N).