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Reaction of copper(I) halides with chiral dithiodianthranilides mdta and bdta afforded polymeric complexes where polynuclear CuX clusters were linked together by ditopic bridging ligands into 1D chains or 2D layer structures. In the case of racemic ligands double stranded chain polymers were formed where the Cu4X4 (X = I or Br) cores are connected by enantiomeric pairs of the ditopic ligands. In contrast, a homochiral mdta ligand created a single stranded hybrid chain involving single mdta enantiomers and solvated Cu5I5 clusters or 2D square (4,4) nets composed of rings comprising four Cu3X3 clusters in nodes and four homochiral ligand molecules in sides with solvent MeCN molecules between the grid layers. The hybrid layer structure obtained from CuCl and the racemic mdta ligand crystallized as a conglomerate that led to its self-resolution into enantiomeric chiral crystals. The solid state CD spectra revealed contribution of two electronic transitions to the diffuse lowest energy absorption band of the complexes. In addition the observed long wavelength Cotton effect sign reflected the helicity of the thiobenzamide chromophore in the ligand unit. At room temperature the solid complexes exhibited weak red phosphorescence near 600–620 nm. Upon cooling down to 10 K all investigated complexes are phosphorescent with average lifetimes of 17–84 μs. [ABSTRACT FROM AUTHOR]

The new material consisting of Gd1.6Dy0.4(WO4)3 incorporated into silica xerogel was prepared via the coprecipitation method. The luminescence properties of the studied material were analyzed by means of emission and excitation spectra, including the result of luminescence lifetimes of Dy(III) ion. The enhanced yellow emission due to the excitation energy transfer from Due to image rights restrictions, multiple line equation(s) cannot be graphically displayed. group to Dy(III) ion upon excitation at λexc = 240 nm is the main result of this paper. [ABSTRACT FROM AUTHOR]

Abstract: In this paper luminescent materials consisting of Ln1.9Pr0.1(WO4)3 where Ln=Gd or La immobilized in silica xerogel matrix have been obtained through a sol–gel approach. The spectroscopic investigations of these materials are presented. Steady state luminescence, luminescence excitation spectra as well as time resolved emission spectra have been measured. The obtained strong red emission due to the excitation energy transfer from group to Pr(III) ion upon excitation at λ exc =240nm is the main result of this paper. Analysis of the luminescence kinetics of Pr(III) ions in studied materials has been performed. The decay curves of Pr(III) luminescence related to 3P0 → 3H4 and 3P0 → 3F2 transitions are reported. High emission intensity and easy preparation of these materials make them promising red phosphors for applications as luminescent materials. [Copyright &y& Elsevier]

We present a synthesis of highly efficient xerogels doped with Ln2-xPrx(WO4)3, where Ln = La or Gd as novel phosphors. For comparison, the synthesis of xerogels doped only with Pr(III) and La(III) ions was made. The photoluminescence properties of Pr(III) ions in xerogels were studied by means of luminescence spectroscopy. In particular, an efficient energy transfer from WO42- to Pr(III) ions was observed and demonstrated by their enhanced luminescence intensity. Especially interesting seems to be strong red acceptor emission observed upon excitation at 240 nm (donor excitation). Therefore, 4f-4f emission makes the system usable for red phosphor applications. Additionally, the emission intensity of the materials was improved by reducing concentration of such quenchers as water molecules and OH groups by the thermal treatment. [ABSTRACT FROM AUTHOR]

The new material consisting of Gd1.6Dy0.4(WO4)3 incorporated into silica xerogel was prepared via the coprecipitation method. The luminescence properties of the studied material were analyzed by means of emission and excitation spectra, including the result of luminescence lifetimes of Dy(III) ion. The enhanced yellow emission due to the excitation energy transfer from Due to image rights restrictions, multiple line equation(s) cannot be graphically displayed. group to Dy(III) ion upon excitation at λexc = 240 nm is the main result of this paper. [ABSTRACT FROM AUTHOR]