Theoretical study of geometric, optical, nonlinear optical, UV–Vis spectra and phosphorescence properties of iridium(III) complexes based on 5-nitro-2-(2′,4′-difluorophenyl)pyridyl

In this work, we studied the structural, optical, nonlinear optical properties , absorption spectra and phosphorescence properties of four cyclometalated heteroleptic iridium complexes [Ir(dFNppy) 2 (PPh3) L ] with dFNppy = 5-nitro-2-(2′,4′-difluorophenylpyridyl, PPh 3 = triphenylphosphine, L = Cl − ( 1 ), NCS − ( 2 ), NCO − ( 3 ) and N 3 − ( 4 ) using DFT and TD-DFT methods. The electronic and geometrical structures of the S 0 and T 1 have been studied and compared. Experimental absorption bands were assigned on the basis of natural transition orbitales, and a good agreement with experience has been obtained. Phosphorescence wavelengths of the four complexes were calculated with vertical and adiabatic methods. Further, linear optical properties (mean polarizability ⟨α⟩ , anisotropy polarizability | α| ), the static first hyperpolarizabilities electric-field-induced second harmonic generation β_//( - 2ω ;ω ,ω) and the hyper-Rayleigh scattering (HRS) first hyperpolarizability β_HRS( - 2ω ;ω ,ω) ), and the depolarization ratio DR of these complexes are calculated by DFT with PBE0 functional in order to understand nonlinear optical properties. Higher polarizability (α ) and first hyperpolarizabilities (β ) of these complexes are obtained. It is also observed an inverse correlation between the predicted β value and the HOMO–LUMO energy difference (Δ ε ).