Exploring the optical and nonlinear optical features of heteroleptic complexes with BODIPY and amido-BODIPY substitutions; A comparative theoretical study

Abstract

In this study, special attention has been paid to understanding the structural effect on electronic structure, absorption spectra and nonlinear optical (NLO) response for a series of heteroleptic diimine dithiolate complexes [M(bpy)(bdt)] (M = Ni, Pd and Pt; bpy = 2,2′-bipyridine, bdt = 1,2-benzenedithiolate) attached to BODIPY and amido-BODIPY dyes through density functional theory (DFT) and time-dependent density functional theory (TD-DFT) methods. Natural bond orbital (NBO) analyses are also performed for scrutinizing the structural properties of the considered heteroleptic complexes. The calculated energy gaps show that the substitution of BODIPY or amido-BODIPY groups on the diimine ligand (bpy) leads to reduce of HLG. In contrast, these substitutions on the dithiolate ligand (bdt) are slightly increased energy gap. Moreover, the entitled substitutions at the diimine position can be red-shifted, and the expansion of absorption range to the near-IR region. It is interesting to note that the BODIPY and amido-BODIPY substitutions dramatically increase the static first hyperpolarizability (β0) value. The results suggest that structural modifications on the diimine and dithiolate ligands using BODIPY and amido-BODIPY dyes can finely tune their linear and nonlinear optical properties.