Weisheng Liu

SYNTHESIS, STRUCTURE AND SPECTROSCOPIC PROPERTIES OF COMPLEXES OF RARE EARTH DITHIOCARBAMATES WITH 2,2′-BIPYRIDYL OR 1, 10-PHENANTHROLINE

Abstract Two series of rare earth complexes with the general formula [RE(Me2Dtc)3(bipy)](RE = La,Pr,Nd,Sm-Yb,Y;Me2Dtc = N,N-dimethyldithiocarbamate; bipy = 2,2′-bipyridyl) and [RE(Et2-Dtc)3(phen)](RE = La,Pr,Nd,Sm-Lu,Y;Et2Dtc = N,N-diethyldithiocarbamate; phen = 1, 10-phenanthroline) have been prepared and some of their chemical properties, IR spectra, electronic spectra and conductivity properties are reported. The structures of [Eu(Me2Dtc)3(bipy)] and [Eu(Et2Dtc)3(phen)] have been determined by single-crystal X-ray diffraction methods. [Eu(Me2Dtc)3(bipy)] crystallizes in the tetragonal system, space group I41/a with a = 16.753(1), c = 39.523(3) A and Z = 16, while [Eu(Et2Dtc)3(phen)] crystallizes in the monoclinic system, space group P21/c with a = 17.029(3), b = 10.652(3), c = 18.726(3) A, β = 96.41(4)° and Z = 4. The central Eu(III) atoms are both octa-coordinated and in a distorted square antiprismatic geometry, each being coordinated to six sulphur atoms of three bidentate dithiocarbamates and to tw...

Synthesis, crystal structure and fluorescence emission of complexes of lanthanide picrates with 2,2′-[1,2-phenylenebis(oxy)]bis(N,N-diphenylacetamide) (PBD)

Abstract Solid complexes of lanthanide picrates with 2,2′-[1,2-phenylenebis(oxy)]bis(N,N-diphenylacetamide) (PBD) have been prepared in ethanol. These complexes have been characterized by elemental analysis, conductivity measurements, IR, electronic and 1H NMR spectroscopies. The crystal and molecular structures of [Y(pic)3(PBD)]·3.8CH3CN have been determined. The crystal structure shows that the Y(III) ion is coordinated to four oxygen atoms of PBD, four oxygen atoms of one bidentate and two unidentate picrates. The coordination number of yttrium is eight. The structure reveals that PBD acts as a tetradentate ligand, forming a ring-like coordination structure similar to those of crown compounds. The Eu(III) complex shows strong emission when excited with 260 nm radiation in the solid state. The intensity ratio 5D0–7F2/5D0–7F1 is 21.5.

SYNTHESIS, CHARACTERIZATION AND STRUCTURE OF COMPLEXES OF LANTHANUM(III) PICRATE WITH N, N, N', N'-TETRAPHENYL-3,6,9-TRIOXAUNDECANEDIAMIDE

Abstract Reaction of lanthanum picrate with N, N, N′, N′-tetraphenyl-3, 6, 9-trioxaundecanediamide (TTD) yields [La (Pic)3 (TTD)], which has been characterized by elemental analysis, IR and 1H NMR spectra and molar conductivity measurements. The complex crystallizes in the orthorhombic space group Pcab with a = 24.006(8), b = 29.140(9), c = 32.084(9) A and D c = 1.60g cm−3 for Z = 16. Refinement of 5676 reflections (l < 2.0[sgrave](l)) out of 12569 unique observed reflections (2°≤2θ<42°) gave R and Rw values of 0.079 and 0.068, respectively.

A novel luminescent chemosensor for detecting Hg2+ based on the pendant benzo crown ether terbium complex

A novel luminescent chemosensor for detecting Hg(2+) with high selectivity, based on a pendant benzo crown ether terbium complex, has been designed and prepared.

Studies on synthesis and infrared and fluorescence spectra of new europium and terbium complexes with an amide-based open-chain crown ether

An amide-based open-chain crown ether ligand and its complexes with europium and terbium were synthesized. The complexes were characterized by elemental analysis, infrared spectra and conductivity. The europium and terbium ions were found to coordinate to the C=O oxygen atoms and pyridine nitrogen atoms. The fluorescence properties of these complexes in DMF and CH3OH/CHCl3 were studied. Under the excitation of UV light, these complexes exhibit characteristic fluorescence of europium and terbium ions. The solvent factors influencing the fluorescent intensity are discussed.

Formation of two (6,3) networks showing structural diversity, Borromean topology and conformational chirality in the same crystal

Reaction of two tripodal ligands, 2,4,6-tris(4-((2-methyl-benzimidazol-1-yl)methyl)phenyl)-1,3,5-triazine (L1) and 1,3,5-tris(4-((2-methyl-benzimidazol-1-yl)methyl)phenyl)benzene (L2), with AgSbF6 led to formation of two types (6,3) networks in one single crystal, of which one is three-fold Borromean topologically entangled while the other is independent, showing the same chirality and sandwiched Borromean stacking.

Synthesis and spectroscopic properties of light lanthanide monoalkyldithio carbamate complexes

Abstract The light lanthanide monoalkyldithiocarbamate complexes with the general formula RNH3·[Ln(RHDtc)4] (R = methyl, ethyl; Ln  LaNd, SmGd) have been prepared and characterized by chemical analyses, IR spectra, electronic spectra, conductivity measurements and TG-DTA techniques. The monoalkyldithiocarbamate anions act as bidentate ligands. The electronic spectral bands of [Ln(EtHDtc)4]−, attributed to electronic transitions of intraligand, charge-transfer, f-f and f-d types, have been investigated in ethanol solution in the spectral range 11.1–52.6 kK.

Synthesis, characterization of 2-(bis-dibutylcarbamoylmethyl-amino)-N, N-dibutyl-acetamide (L) lanthanide picrate complexes (Ln=Nd, Eu, Tb) and the crystal structure of [Tb(pic)3L]

Abstract Solid complexes of lanthanide picrate with the ligand 2-(bis-dibutylcarbamoylmethyl-amino)-N, N-dibutyl-acetamide (L), [Ln(pic)3L] (Ln=Nd, Eu, Tb), have been prepared and characterized by elemental analysis, conductivity measurements, DTA and TGA analysis, IR and 1H NMR spectra. For the terbium complex, X-ray measurements show that Tb(III) ion is 9-coordinated by three oxygen atoms and one nitrogen atom of L and five oxygen atoms of picrate groups. Molecule B has a clockwise structure due to the screw coordination arrangement of the tripod-type ligand.

Synthesis and infrared and fluorescence spectral properties of luminescent terbium and europium complexes with open-chain carboxylate crown ethers

Two open-chain carboxylate crown ether ligands and their terbium(III) and europium(III) complexes were synthesized and characterized. The terbium and europium ions were found to coordinate to the carboxylate oxygens. The fluorescence properties of europium complexes in the solid state and terbium complexes in the solid state and in the organic solvent were studied in detail, respectively. Under the excitation of ultraviolet light, strong green fluorescence of solid terbium complexes and red fluorescence of solid europium complexes were observed. These observations show that the two ligands favor energy transfer to the emitting energy level of Tb(3+). Some factors that influencing the fluorescent intensity were also discussed.

SYNTHESIS AND CRYSTAL STRUCTURE OF COMPLEXES OF ERBIUM(III) PICRATE WITH N,N,N',N'-TETRAPHENYL-3,6,9-TRIOXAUNDECANEDIAMIDE

Abstract Reaction of erbium picrate with N,N,N′,N′-tetraphenyl-3,6,9-trioxaundecanediamide (TTD), yielded [Er(Pic)3(TTD)]. Its crystal structure shows that the ErIII ion is coordinated to five oxygen atoms of TTD, three oxygen atoms of two picrates and one oxygen atom of H2O giving a coordination number of nine. The TTD molecule acts as a multidentate ligand forming a ring-like coordination structure similar to those of crown compounds.