Luminescence from a highly asymmetric nine-coordinate tricapped trigonal prismatic Sm(III) complex

The nine-coordinate complexes of tris(dibenzoylmetanato)La(III) and Sm(III) with tptz were synthesized and thoroughly characterized. The H-1 NMR spectrum of [La (dbm)(3)(tptz)]center dot CH3CN is consistent with the coordination of three dbm and one tptz. The tricapped trigonal prism geometry of [Sm(dbm)(3)(tptz)]center dot CH3CN complex is revealed by single crystal X-ray diffraction analysis. The shape 2.1v analysis authenticates the tricapped trigonal prism geometry of [Sm(dbm)(3)(tptz)]center dot CH3CN complex. The Sm(III) is coordinatively saturated by the coordination of six oxygen atoms from dbm units and two pyridyl and one triazine nitrogen atoms from tptz moiety. The steady-state and time resolved photoluminescence of the solid [Sm(dbm)(3)(tptz)]center dot CH3CN and its PMMA hybrid films of different concentration are investigated and discussed. The complex has only one emitting center since the decay times are fitted by mono-exponential function. The higher PL intensity of (4)G(5)/(2) -> H-6(7/2) (Delta J = 1, magnetic-dipole transition) transition compared to (4)G(5/2) -> H-6(9/2) (Delta J = 2, electric-dipole transition), in the case of 3% (w/w) PMMA hybrid film is the result of strong vibrionic coupling. Although the PL intensity of two transition are different even then the decay times of the transition are roughly similar in magnitude. The stark splitting of electric-dipole (4)G(5/2) -> H-6(9/2) transition in the spectrum of 3% film is interesting and leads to believe a strong coupling between states of f-electrons and electric fields of the surrounding ligands.