Color tuning and violet light emission via coordination of pyrazole in tris (benzoyltrifluoroacetonate)Sm(III)

The complex [Sm(btfa)(3)(H2O)(2)] was synthesized in 86.57 % yield. Such high yield of [Sm(btfa)(3)(H2O)(2)] complex has not been reported so far. Single crystal X-ray diffraction (SC-XRD) analysis demonstrates that [Sm (btfa)(3)(H2O)(2)] and [Sm(btfa)(3)(pz)(2)] (btfa = anion of 4,4,4-trifluoro-1-phenyl-1,3-propanedione and pz = pyrazole) complexes are octa-coordinated. According to the SHAPE v2.1 analysis, [Sm(btfa)(3)(H2O)(2) has triangular dodecahedron geometry and [Sm(btfa)3(pz)2] complex has snub disphenoid geometry. Furthermore, elemental analysis, thermal analysis (TGA/DTG), and ATR-IR spectroscopy are used to characterize these synthesized complexes. The decay curve of (4)G(5/2) -> H-6(9/2) emission transition is fitted by a mono-exponential function for both complexes. The violet emission with a longer luminescence lifetime is observed from [Sm(btfa)3(pz)2] (69.78 +/- 0.29 mu s) which is more than ten times longer than the pink light emitter [Sm(btfa)(3)(H2O)(2)] (6.43 +/- 0.08 mu s). The quantum yield of solid samples was evaluated under ligand excitation by the absolute method using the integrating sphere. The absolute quantum yield of the violet light emitter complex (3.10 %) is seven times larger than the pink light emitter complex (0.44 %).