A series of complexes Ln(Pip)3(Phen) (Ln(iii) = La, Ce-Nd, Sm-Lu, Y; HPip (CAPh type ligand) = 2,2,2-trichloro-N-(dipiperidin-1-yl-phosphoryl)acetamide, Phen = 1,10-phenanthroline) has been synthesized. The lanthanum(iii) doped europium(iii) complexes ([LaxEu1-x(Pip)3(Phen)], x = 0.99, 0.95, 0.50) have been obtained by the co-crystallization method. The complexes have been characterized by means of X-ray diffraction, IR, (1)H and (31)P-NMR and absorption spectroscopy. Emission and excitation luminescence spectra were recorded at 295 and 77 K. The lifetime values (τ) for the emission of all europium complexes were determined. The (5)D0 luminescence quantum efficiency is 73-89%. The symmetries of the nearest europium surrounding in pure and doped complexes were evaluated from the Stark splitting of (5)D0-(7)FJ transitions. Crystal structures of [Ln(Pip)3(Phen)] (Ln = Nd (1), Eu (2) and Tb (3)) have been determined. Lattice parameters of the [Ln(Pip)3(Phen)] (Ln = Tb, Yb) and the doped [LaxEu1-x(Pip)3(Phen)] (x = 0.99, 0.95, 0.50) complexes have been measured. The presence of four polymorphs within a number of rare earth elements has been estimated: two in triclinic (Ln1 = La, Nd; Ln2 = Eu), one in the monoclinic (Ln3 = Tb) and one in the rhombic (Ln4 = Tb, Yb) symmetry. Complex 3 can be obtained in two crystal modifications: monoclinic and orthorhombic ones.

Surface morphology and photoluminescence (PL) properties of both microcrystalline cellulose (MCC), microcrystalline powders of the alkali metals nitrites MNO2 (M = Na. K, Cs) (MCN) and two-component composite materials based on the MCC and MCN have been studied and characterized by means of optical microscopy and luminescence spectroscopy.

The Sr3LnInSnO8(Ln = La, Pr, Nd) layered perovskites were synthesized and their structures have been determined by X-ray powder diffraction. Luminescence properties of the synthesized polycrystalline compounds Sr3PrInSnO8and Sr3NdInSnO8were investigated. Photoluminescence spectra of Sr3PrInSnO8substantially depend on excitation wavelength unlike Sr3NdInSnO8compound. The correlations between peculiarities of the crystal structures and photoluminescence properties have been discussed.

1 Abstract. The Sr 3 LaTa 3 O 12 layered powdered perovskitelike compounds were obtained by heat treatment of coprecipitated hydroxy-carbonates. Photoluminescent (PL) properties of the Sr 3 LaTa 3 O 12 were investigated at the first time. Strongly overlapped components peaked at 535, 585 and 630 nm compos emission spectra of the materials under study. The luminescent data were analyzed and preliminary assumptions about origin of given spectra have been made.