Ling Fan

Photoluminescence behavior of europium (III) complexes containing 1-(4-tert-butylphenyl)-3-(2-naphthyl)-propane-1,3-dione ligand

Three novel europium complexes with 1-(4-tert-butylphenyl)-3-(2-naphthyl)-propane-1,3-dione (TNPD) and 2,2-dipyridine (Bipy) or 1,10-phenan-throline (Phen) were synthesized and confirmed by FT-IR, (1)H NMR, UV-vis absorption and elemental analysis. Photoluminescence behavior of complexes Eu(TNPD)3, Eu(TNPD)3·Bipy and Eu(TNPD)3·Phen were investigated in detail. Their emission spectra exhibited the characteristic emission bands that arise from the (5)D0→(7)FJ (J=0-4) transitions of the europium ion in solid state. Meanwhile, the results of their lifetime decay curves indicated that only one chemical environment existed around the europium ion. The intrinsic luminescence quantum efficiency (η) and the experimental intensity parameters (Ωt) of europium complexes were determined according to the emission spectra and luminescence decay curves in solid state. The complex Eu(TNPD)3·Phen showed much longer lifetime (τ) and higher luminescence quantum efficiency (η) than complexes Eu(TNPD)3 and Eu(TNPD)3·Bipy.

Preparation and photophysical properties of thienothiophene functionalized difluoroboron bis-β-diketonate complexes

A series of six new thienothiophene functionalized difluoroboron bis-β-diketonates were synthesized and characterized. Their photophysical properties were investigated by UV-vis absorption, fluorescence spectroscopy and the method of CIE chromaticity in solution and powders. The results showed that these difluoroboron complexes yielded a blue-green emission at 474-500 nm in DMF solution and emitted a green to yellow emission at 541-587 nm in powders. Especially, the complex 3c showed the stronger fluorescence intensity, much higher quantum yield (Φu = 0.89) in DMF solution and larger Stokes shifts (∆λstokes = 149 nm), longer lifetime value (τ = 3.54 ns) in powders as compared to other complexes. The CIE coordinate of the complex 3c was positioned in an ideal orange-yellow region of the chromaticity diagram. Meanwhile, their electrochemical properties were also studied by the cyclic voltammetry; the HOMO, LUMO energy levels and energy band gaps were determined from the onset oxidation and reduction potentials.

Bis{1-[4-(benz-yloxy)phen-yl]-4,4,4-tri-fluoro-butane-1,3-dionato(1-)}dipyri-dine-cobalt(II).

In the title compound, [Co(C17H12F3O3)2(C5H5N)2], the CoII ion is situated on a twofold rotation axis, coordinated by four O atoms from two 1-[4-(benzyloxy)phenyl]-4,4,4-trifluorobutane-1,3-dionate(1−) (L) ligands and two N atoms from two pyridine ligands in a distorted octahedral geometry. The two pyridine rings form a dihedral angle of 84.63 (7)°. The two benzene rings in L are twisted at 58.83 (5)°. Weak intermolecular C—H⋯F hydrogen bonds consolidate the crystal packing.