Synthesis and photoluminescent studies of orange–red emissive samarium(III) complexes with 1,1,1-trifluoro-5,5-dimethyl-2,4-hexanedione and 2,2′-bipyridine and its distinctive analogous

Highly luminescent octa-coordinated samarium(III) complexes including [Sm(TFDH)₃(Bpy)] (Sm1), [Sm(TFDH)₃(S₁)] (Sm2), [Sm(TFDH)₃(S₂)] (Sm3) and [Sm(TFDH)₃(S₃)] (Sm4) were synthesized utilizing fluorinated β-diketone i.e. 1,1,1-trifluoro-5,5-dimethyl-2,4-hexanedione (TFDH) and bidentate auxiliary ligands. Here, S₁ is 5,5ʹ-dibromo-2,2′-bipyridine; S₂ is 5-bromo-5ʹ-(3,4-(ethylenedioxy)thien-2-yl)2,2′-bipyridine and S₃ is 5,5′-bis(3,4-(ethylenedioxy)thien-2-yl)2,2′-bipyridine. Different properties of prepared complexes were examined using numerous characterization techniques such as elemental, FT-IR, ¹H NMR, absorption and thermogravimetric analyses. Nuclear magnetic resonance (NMR) data affirms the coordination of three TFDH units and one bidentate ligand with metal ion in each complex. Sm(III) complexes exhibit thermal stability up to 250 °C when subjected to an inert atmosphere composed of nitrogen (N₂) gas. The luminescent characteristics of the powdered Sm1-Sm4 complexes were also investigated. Each complex displays distinct peaks at around 564, 605, 648 and 707 nm in their emission profiles. The orange-red emission of these complexes was observed via colorimetry which strongly aligns with the highly intense peak observed at 648 nm (⁴G_5/2→⁶H_9/2). The strong luminosity and color coordinates suggest that the complexes could serve as potential candidates for use in OLEDs and display panel.