Theoretical investigation of photophysical properties for a series of iridium(iii) complexes with different substituted 2,5-diphenyl-1,3,4-oxadiazole

A quantum chemical investigation from structural and electronic properties and some charge-transport parameter viewpoints was performed on several homoleptic iridium complexes [(C^N)₂Ir(pic)] with the 2,5-diaryl-1,3,4-oxadia-zoles moiety in C^N ligands, where pic represents the picolinate ancillary ligand. Complex 2 exhibits its blue phosphorescent emission with maxima at 485 nm. Furthermore, to obtain the mechanism of high phosphorescence yield in 2, we estimated the radiative rate constant k_r, the contribution of ³MLCT in the T₁ state, S₁-T₁ energy gap ΔE_S1-_T1, and the transition dipole moment in the S₀ → S₁ transition μ_S1 for 2. Comparison of calculated results for the four complexes shows that the designed complex 2 may possess higher photoluminescent quantum efficiency than the others, making it a potential candidate as an efficient blue-emitting material.