Structural, magnetic and up-conversion properties of YF3: Yb/Ln (Ln = Er, Tm, Ho) solid solutions

In this paper, we investigated YF3: Yb/Er, YF3: Yb/Tm, and YF3: Yb/Ho solid solutions prepared by reaction of an appropriate amount of oxides with ammonium difluoride (NH4HF2) as a fluorinating agent. These samples were characterized by Xray diffraction (XRD), magnetic measurements, and up-conversion (UC) photoluminescence spectra. The results show that all samples are single-phase and crystallize in an orthorhombic crystal structure of the ?-YF3 structure type. Above 100 K, the measured molar magnetic susceptibility was fitted by the Curie-Weiss law and the average effective magnetic moments for the observed samples were obtained. All the samples showed pure paramagnetic behavior. When doped with lanthanide elements (Yb/Er, Yb/Tm, Yb/Ho), YF3 solid solutions can emit characteristic green, red, blue, and near IR light under the excitation of a 980 nm laser diode.

Synthesis and Characterization of Co(II) and Ni(II) complexes of Schiff base derived from Ninhydrin and Valine

In this study, Complexes of Co (II) and Ni (II) ions with Ruhmann’s purple (ligand) were successfully synthesized and characterized. The complexes of NiL2and CoL2were synthesized by using template condensation synthesis method and characterized by melting point, solubility, elemental analysis, and molar conductance, and magnetic susceptibility, infrared and electronic spectral studies. The complexes, NiL2and CoL2 are soluble in ethanol, partially soluble in Diethyl ether and chloroform and insoluble in hexane and petroleum ether. The complexes, NiL2and CoL2 neither melt nor decompose up to 4200C. The molar conductance of NiL2and CoL2 was 42 Scm2/mol and 46Scm2/mol in respectively. The molar magnetic susceptibility of two complexes was 1.74 BM for NiL2 and 2.76 BM for CoL2. The metal to ligand ratio of both metal complexes was 1:2; both metal complexes are non-electrolytes in ethanol and are paramagnetic at 210C. Based on the spectral data and other analytical data, monobasic ONO donor behavior of the ligand (Ruhmann’s purple) generates octahedral geometry for the pink-green colored Ni (II) complex and green colored Co (II) complex.

Structure of 2:1 cobalt(III) complexes derived from arylazocitrazinic acid

1H, 13C NMR and MS spectra of the 2:1 cobalt(III) complexes, the azo coupling products of 2-aminophenol or 2-aminobenzoic acid with the citrazinic acid, were measured and analysed. It was found that the cobalt atom is six-coordinated being bound to two oxygens (one from primary and one from secondary component) and the nitrogen of 2-aminophenol or 2-aminobenzoic acid. Molar magnetic susceptibility data proved the presence of Co(III). Diazotisation of 2-aminophenol or 2-aminobenzoic acid and subsequent coupling reaction with citrazinic acid and complexation of the formed azo product proceeded on standard way.