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We have studied the effect of Bi3+ and Ca2+ cation additions and partial Si, P, and V substitutions for Mo on the photoluminescence of NaY1−xEux(MoO4)2 scheelite-like red phosphors. The results demonstrate that the photoluminescence intensity in NaY1 − xEux(MoO4)2 doped with Bi3+ and Ca2+ increases with europium concentration, up to x = 0.5, without concentration quenching. When the atomic fraction of Bi3+ is 0.2, it has a sensitizing effect on Eu3+. Ca2+ doping to an atomic fraction of 0.45 also increases the photoluminescence intensity. Partial Si, P, and V substitutions for Mo have little effect on the photoluminescence intensity.

The complex of CdCl2 with 2-(3,5-dimethylpyrazol-1-yl)-4-methylquinoline (L), Cd2(L)Cl4 (I), is synthesized. According to the X-ray diffraction data, the structure of coordination polymer I is formed by chains in which two crystallographically independent Cd atoms linked by the bridging Cl atoms have different coordination numbers (5 and 6) and different environments. Five Cl atoms form the coordination polyhedron of the Cd(2) atom: a square pyramid (Cd-Cl 2.554(3)–2.689(3) A) completed to a bipyramid by the CI atom at a substantially longer distance of 2.865(4) A. Two Cl atoms and the N atom of quinoline fragment L are arranged in the equatorial plane of the coordination polyhedron of the Cd(1) atom, which is a distorted trigonal bipyramid. The axial vertices are occupied by the N atom of the pyrazole cycle of L and the Cl atom. Five-membered metallocycles CdCN3 are formed upon the coordination of bidentate chelating ligands L. The planes of L of two adjacent chains are parallel (the distances between them are ∼3.5 A), which suggests the π-π interaction between the planes. The luminescence excitation spectrum of compound I has a broad band with λmax = 350 nm. The spectrum of bright blue photoluminescence of compound I (300 K, λexc = 340 nm) contains an intense band with λmax = 420 nm.

Using the single crystal X-ray diffraction data (150 K, Bruker X8 Apex CCD autodiffractometer, MoK α radiation), the crystal structure of the [Cd2L2Cl4]·CH2Cl2 (L = pyrazolylquinoline, the derivative of monoterpenoid (+)-3-carene) compound is determined. Crystals are monoclinic, unit cell parameters are: a = 10.7005(4) A, b = 16.8491(4) A, c = 11.9658(4) A, β = 93.308(1)°, P21 space group. The structure is formed from discrete acentric molecules of a binuclear [Cd2L2Cl4] complex and uncoordinated CH2Cl2 molecules. The Cd2+ ions coordinate N atoms of bidentate chelating ligands L, which leads to the closure of two five-membered chelate CdN3C rings. The coordination sphere of Cd atoms also includes three Cl atoms (two bridging and one terminal), consequently, two CdCl3N2 coordination sites and a Cd2Cl2 metal ring are formed. The Cl3N2 polyhedra have the form of distorted tetragonal pyramids. The CH2Cl2 molecules located in the channels formed by the complexes are linked with them by weak H-bonds. The excitation spectra of L and the CdLCl2 compound contain bands with λmax of 352 nm and 360 nm respectively. At 300 K and λexcit 350 nm, in the photoluminescence spectrum of L a rather intense broad split band with λmax 372 nm and 386 nm is observed. The photoluminescence spectrum of the CdLCl2 compound contains a broad band with λmax 418 nm. The photoluminescence intensity of this compound is significantly lower than that of L.

A series of zinc(II) and cadmium(II) complexes with 4-(3,5-diphenyl-1H-pyrazol-1-yl)-6-(piperidin-1-yl)pyrimidine (L), ZnLCl2, CdLCl2, ZnL2Cl2, CdL2Cl2, CdL2Cl2·0.5Me2CO·1.5H2O and CdL2Cl2·0.5CHCl3·0.5H2O, have been synthesized. The compounds ZnLCl2 and CdLCl2 were obtained in a M:L = 1:1 molar ratio in EtOH solutions, while ZnL2Cl2 and CdL2Cl2 were isolated in a M:L = 1:3 molar ratio in EtOH/Me2CO mixtures. Surprisingly, attempts to crystallize CdLCl2 from EtOH/Me2CO mixture afforded single crystals of a compound, having 1:2 metal-to-ligand stoichiometry, CdL2Cl2·0.5Me2CO·1.5H2O, instead of a complex with 1:1 stoichiometry. At the same time, crystallization of CdL2Cl2 from Me2CO/CHCl3 mixture afforded CdL2Cl2·0.5CHCl3·0.5H2O single crystals. According to X-ray crystal structure data, ZnLCl2, ZnL2Cl2, CdL2Cl2·0.5Me2CO·1.5H2O and CdL2Cl2·0.5CHCl3·0.5H2O complexes have molecular mononuclear structures. The molecules of L adopt bidentate chelating binding mode being coordinated to the metal ions through N2 atom of the pyrazole and N3 atom of the pyrimidine rings. The coordination core of zinc atom in ZnLCl2 complex is a distorted ZnN2Cl2 tetrahedron. The coordination cores of metal atoms in the structures of ZnL2Cl2, CdL2Cl2·0.5Me2CO·1.5H2O and CdL2Cl2·0.5CHCl3·0.5H2O are the distorted cis-MN4Cl2 (M = Zn, Cd) octahedra. In the structure of ZnL2Cl2 double lone pair(N(piperidine))–π(pyrimidine) interactions were observed. The photoluminescent properties of L, ZnLCl2, CdLCl2, ZnL2Cl2 and CdL2Cl2 were studied in the solid state under the same experimental conditions. These compounds were found to display bright blue luminescence. Highest relative intensity of emission was detected for ZnL2Cl2.

Zinc(II) and cadmium(II) complexes, ZnL2 ⋅ 0.5H2O, ZnL2 ⋅ 2MeOH and CdL2 ⋅ 1.5H2O, based on a new hybrid compound, 2-(3,5-dimethyl-1 H-pyrazol-1-yl)-6-(4-methoxyphenyl)pyrimidine-4-carboxylic acid (HL), have been synthesized. They are the first examples of metal complexes with pyrazolylpyrimidinecarboxylates. The complex ZnL2 ⋅ 2MeOH was structurally characterized. It has mononuclear structure; zinc atom is in the distorted octahedral coordination polyhedron 4N + 2O formed by donor atoms of two coordinated L− ions. The compounds HL, ZnL2 ⋅ 0.5H2O and CdL2 ⋅ 1.5H2O manifest bright blue photoluminescence.

New polymeric cadmium complexes, α-[CdLCl2]n (1), [CdL2Cl2]n (2) and β-[CdLCl2]n (3) (L = 4-amino-2,1,3-benzothiadiazole), were obtained as products of the reaction of CdCl2 with L. The synthetic procedures allowing isolation of pure 1–3 were optimized. The structures of 1–3 were established by single-crystal X-ray diffraction and the compounds were characterized by UV–Vis and IR spectroscopy. In these compounds, L is either μ-bridging (1) or terminal (2 and 3). The UV–Vis spectra of the complexes in the solid state resemble that of free L. However, coordination of L leads to a significant shift of emission in photoluminescence spectra from yellow (free L) to red (1–3).