Preparation and photoluminescent analysis of Sm3+ complexes based on unsymmetrical conjugated chromophoric ligand

The octa-coordinated complexes of Sm(III) with β-diketone and nitrogen-heterocyclic bidentate auxiliary moiety were prepared and characterized spectroscopically. Spectral outcomes of complexes have suggested the isostructural behavior of ternary complexes. Optical bandgap (E_g) values of complexes were evaluated from Tauc’s plot. The photoluminescence emission spectra of ternary complexes show Sm³⁺-based peaks at 566, 601, 648, and 707 nm attributed to ⁴G_5/2 → ⁶H_J (J = 5/2–11/2) transitions. Most intense peak at 648 nm is responsible for orange-red emanation of samarium complexes. Colorimetric analysis of complexes supports the results of emission spectra. The fascinating optical properties of ternary metal complexes in the orange-red visible spectral region might be valuable in designing optoelectronic devices and displays.