Minyu Tan

A study of an oxovanadium(V) complex with a tridentate schiff base ligand

A tridentate dibasic Schiff base ligand with an ONO donor set reacts with (n—C4H9)4NVO3 in the presence of a small amount of acetic acid to form a monomeric and five-coordinated oxovanadium(V) complex of the type [VO(L)(OCH)2CH3)] (H2L=N-benzoylacetone-m-Bromobenzoylhydrazone) The title complex has been characterized by elemental analysis. IR, EPR, 1H NMR, electronic absorption spectra and conductance measurements. The results of EPR spectrum and electronic absorption spectra confirm that the oxidation state of the vanadium is + 5. A biological effect of the ligand and its complex has been studied. The X-ray structure analysis reveals that the coordination environment of the vanadium atom is a square pyramid with the oxo-ligand occupying the apical position.

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, properties and structure of lanthanide complexes with N,N-diethyldithiocarbamate and 2,2′-bipyridyl

Abstract Fourteen new ternary complexes with the general formula [M(Et 2 Dtc) 3 (bipy)] (M = La, Pr, Nd, Sm-Lu, Y; Et 2 Dtc = N,N-diethyldithiocarbamate; bipy = 2,2′-bipyridyl) have been prepared and characterized by chemical analysis, IR spectra, electronic spectra and conductivity measurements. The crystal and molecular structures of [Er(Et 2 Dtc) 3 (bipy)] have been determined by single-crystal X-ray diffraction techniques. The central Er III atom is octa-coordinated and in a distorted dodecahedral geometry, being coordinated to six sulphur atoms of three Et 2 Dtc ligands and to two nitrogen atoms of bipy ligand.

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.

Study on tribological properties of the complex of rare earth dialkyldithiocarbamate and phenanthroline in lubricating grease

Abstract Three complexes of rare earth dialkyldithiocarbamate (DTC) and phenanthroline (Phen) were synthesized. Their tribological properties as additives in lithium grease were evaluated using a four-ball machine and a SRV machine. As a comparison, the tribological properties of molybdenum dialkyldithiocarbamate (MoDTC) as an additive in lithium grease were also investigated. The thermal stabilities of rare earth complexes were also investigated with a thermal gravity analyzer. The results indicate that these rare earth complexes possess excellent load-carrying capacity, antiwear and friction reduction properties, and high thermal stability. Their extreme pressure properties are superior to that of MoDTC. At lower concentration and lower load, the antiwear properties of lanthanum and neodymium complexes are superior to those of MoDTC. At lower concentration and higher load, the antiwear properties of the these rare earth complexes are inferior to those of MoDTC. But the wear increases, as the increase of concentration of rare earth complex. The results of Auger electron spectroscopy and X-ray photoelectron spectroscopy analyses indicate that these rare earth complexes as additives in lithium grease can form a protective film containing rare earth oxide, sulfate and an organic compound containing sulphur and nitrogen on a rubbed surface. Especially, the lubricating film rich in rare earth and sulphur contributed largely to the excellent tribological properties of EDTC. Ln. Phen.

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 and characterization of mixed-ligand 1,3-dithiole-2-thione-4,5-dithiolate and 1,10-phenanthroline complexes of lanthanide chloride and their iodinated materials

Abstract The lanthanide complexes of general formula K 2 [Ln(dmit)( phen ) 2 Cl 3 · 6H 2 O (Ln = La, Nd, Sm, Gd, Er, Y; dmit 2− = 1,3-dithiole-2-thione-4, 5-dithiolate anion; phen = 1,10-phenanthroline) have been prepared and characterized by means of elemental analysis, IR spectra, electronic spectra and conductivity measurements. These complexes behave as insulators at 25°C as compacted pellets. On doping iodine into the complexes, they have been partially oxidized to afford K 2 [Ln(dmit)( phen ) 2 Cl 3 ] · I x (Ln = La, x = 3.5; Ln = Er, x = 3.0), whose electrical conductivities are raised to the range of semi-conductors. The nature of the iodine species in these solids is determined by UV-visible and resonance Raman spectroscopies.

Synthesis and Characterization of Light Lanthanide Complexes with Monosubstituted Dithiocarbamates

Abstract Monosubstituted dithiocarbamate complexes of light lanthanides of the type [(RNHCSS)4Ln]N(Bu-n)4·nH2O (where R [dbnd] Ph, p-MePh; Ln[dbnd]La-Gd, excluding Pm; n = O or 2) have been synthesized and characterized by chemical analysis, IR spectra, UV spectra, conductivity measurements and TG-DTA techniques. Spectral studies show that the dithiocarbamate group behaves as a bidentate ligand. Referee I: K. Kasuga Referee II: S. Yamada