Preparation, characterization and luminescence behavior of some samarium complexes

The synthesis of luminescent complexes of Sm(III) with the general formula [Sm(L)_(3)·(X)] was done in powder form. In the formula, L is 6-methyl-4-oxo-4 H-1-benzopyran-3-carboxaldehyde and X represents 2H_(2)O(C1), 1,10-phenanthroline(C2), 2,20-bipyridine(C3);bathophenanthroline(C4) and neocuproine(C5). The complexes were characterized by using various analytical and spectroscopic tools like elemental analysis, electrospray ionization mass spectrometry(ESI–MS+), Fourier transform infrared spectroscopy(FTIR), ultraviolet–visible(UV–Vis) spectroscopy, thermo-gravimetric analysis/differential thermal gravimetric analysis(TGA/DTG), field emission scanning electron microscopy(FESEM), powder X-ray diffraction(XRD), and photoluminescence(PL)studies. TGA/DTG showed high thermal stability of synthesized complexes. Powder XRD depicts that the average particle size lies in the nano-range. On monitoring at the excitation wavelength of 370 nm, the complexes display characteristic luminescence peaks of Sm(III) at ~564,~600 and ~647 nm assigned to^(4)G_(5/2)→^(6)H_(5/2),^(4)G_(5/2)→^(6)H_(7/2), and ^(4)G_(5/2)→6H9/2 transitions, respectively, with the most intense transition at ~600(orange emission) and~647 nm(bright red emission) in liquid and powder state, respectively. The investigations demonstrate that the synthesized novel complexes might be practically useful in electroluminescent devices, bio-assays, and liquid lasers due to their attractive photoluminescent properties.