Correlation Between The Stability Of Carbonates In Ternary Ln2o3-H2o-Co2 Hydrothermal Systems And Lanthanide Systematics

Phase diagrams for ternary Ln2O3-H2O-CO2 systems for the entire lanthanide series (except promethium) were studied at temperatures in the range 100–950 °C and pressures up to 3000 bar. The phase diagrams obtained for the heavier lanthanides are far more complex, with the appearance of a number of stable carbonate phases. New carbonates isolated from lanthanide systems (Ln ≡ Tm, Yb, Lu) include Ln6(OH)4(CO3)7, Ln4(OH)6-(CO3)3, Ln2O(OH)2CO3, Ln6O2(OH)8(CO3)3 and Ln12O7(OH)10(CO3)6. Stable carbonate phases common to all the lighter lanthanides are hexagonal LnOHCO3 and hexagonal Ln2O2CO3. Ln2(CO3)3• 3H2O is stable from samarium onwards and orthorhombic LnOHCO3 is stable from gadolinium onwards. On the basis of the appearance of stable carbonates, four different groups of lanthanides were established: lanthanum to neodymium, promethium to europium, terbium to erbium and thulium to lutetium. Gadolinium is the connecting element between groups II and III. This is in accordance with the tetrad classification for f transition elements.

Complexes of Lanthanide Perchlorates with N-(2-Pyrimidyl)benzamide

New complexes of lanthanide perchlorates with N-(2-pyrimidyl)benzamide (BApymH) of the general formulae [Ln(BApymH)4](ClO4)3 (where Ln = La-Yb and Y) have been synthesised and characterised by chemical analysis, molar conductivity and physical methods such as infrared and electronic spectra in the visible region. Molar conductance and infrared data point to the ionic nature of the per-chlorate groups in the complexes. IR data unequivocally proves that the coordination of the ligand to the metal ion takes place in a bidentate fashion through the oxygen of the secondary amide and nitrogen of the pyrimidine ring. From a comparison of the visible electronic spectral shapes of the Nd3+ and Ho3+ complexes with those reported in the literature, an eight coordinate geometry around the metal ion has tentatively been assigned in all the complexes.

Lanthanide perchlorate complexes of 4-cyano pyridine-N-oxide, 4-chloro 2-picoline-N-oxide and 4-dimethyl amino-2-picoline-N-oxide

Complexes of lanthanide perchlorates with 4-cyano pyridine-1-oxide, 4-chloro 2-picoline-1-oxide and 4-dimethyl-amino 2-picoline-1-oxide have been isolated for the first time and characterized by analysis, conductance, infrared, NMR and electronic spectra. The complexes of 4-cyano pyridine-1-oxides have the composition Ln(CyPO)6(ClO4)3. 2H2O (Ln=La, Sm, Dy and Ho); Ln(CyPO)7 (ClO4)3. 2H2O (Ln=Pr, Nd, Er and Yb); and Ln(CyPO)5 (ClO4)3. 2H2O (Ln=Gd and Tb). The complexes of 4-chloro 2-picoline-1-oxide analyse for the formulae Ln(CpicO)6 (ClO4)3 (Ln=La, Pr, Nd and Ho); and Ln (CpicO)5 (ClO4)3 (Ln=Er and Yb), and those of 4-dimethylamino 2-picoline-1-oxide for Ln(DMPicO)6 (ClO4)3 (Ln=La and Nd); Ln(DMPicO)7 (ClO4)3 (Ln=Gd, Er and Yb); and Ln(DMPicO)8 (ClO4)3 (Ln=Dy and Ho).

Complexes of lanthanide perchlorates with two new " O,N,O " ligands derived from antipyraldehyde and acetic and benzoic acid hydrazides

Antipyrlne is a well known llgand for lanthanldes (i). A forage through the organic literature of pyrazolones reveals that the 4-position of antipyrlne is amenable to a wide variety of organic reactions. It should thus be possible to introduce suitable functional groups at this position and design new multidentate ligands for metal ions. It is also found that the coordination chemistry of lanthanides is much less well developed and far fewer ligands have been used for complexation with lanthanide ions compared to that of the d-transition metal ions.

Lanthanide perchiorate complexes of 4-cyano puridine N-oxide, 4-chloro 2-picoline-B-Oxide and 4_dimethyl amino-2-Picoline N Oxide

Complexes of lanthanide perchlorates with 4-cyano pyridine-1-oxide, 4-chloro 2-picoline-1-oxide and 4-dimethyl amino 2-picoline-1-oxide have been isolated for the first time and characterized by analysis, conductance, infrared, NMR and electronic spectra.

Complexes of lanthanide iodides with 3-methylpyridine-1-oxide

Complexes of lanthanide iodides with 3-methylpyridine-1-oxide of the formula Ln(3-MePyO)8I3.xH2O where x = 0 for Ln = La and Tb, x = 1 for Ln = Pr, and x = 2 for Ln = Nd, Sm, Dy, Yb, and Y have been prepared and characterized by chemical analyses, conductance, infrared, proton nmr, and DTA data. Infrared and proton nmr data have been interpreted in terms of the coordination of the ligand to the metal ion through the oxygen of the N—O group. Proton nmr spectrum of the Yb(III) complex is indicative of a restricted rotation of the pyridine ring about the N—O bond.

Lanthanide coordination in dimethyl sulphoxide and antipyrine complexes of rare earth nitrates

Abstract is not available.

Pyridine-1-oxide complexes of lanthanide iodides

Pyridine-1-oxide complexes of lanthanide iodides of the formulaLn(PyO)8I3 whereLn=La, Pr, Nd, Tb, Dy, Er, and Yb have been prepared and characterised by analyses, molecular weight, conductance, infrared and proton NMR data. Proton NMR and IR data have shown the coordination of the ligand to the metal through the oxygen atom of the N–O group. NMR data have been interpreted in terms of a distorted square antiprismatic geometry in solution.

Complexes of lanthanide iodides with 4-methylpyridine-1-oxide and 2-methylpyridine-1-oxide

Complexes of lanthanide iodides with 4-methylpyridine-1-oxide and 2-methylpyridine-1-oxide of the formulae Ln(4-MePyO)8I3.xH2O (x=0 or 2) and Ln(2-MePyO)5I3.xH2O (x=0, 1 or 3) have been prepared and characterized by analyses, conductance, infrared and proton NMR data. Infrared spectra of the complexes indicate that the coordination of the ligand to the metal ion takes place through the oxygen of the N-O group of the ligand. Proton NMR data for the paramagnetic complexes indicate that both contact and pseudocontact interactions are responsible for the isotropic shifts. Proton NMR spectra of the 2-methylpyridine-1-oxide complexes indicate a restricted rotation of the ligand about the N-O group.

4-Nitro and 4-chloro pyridine-N-oxide complexes of lanthanide perchlorates

Adducts of lanthanide perchlorates with 4-nitro and 4-chloro pyridine-Noxides (4-NPNO and 4-CPNO respectively) have been synthesised for the first time and characterised by analysis, electrolytic conductance, infrared, proton-NMR and electronic spectral data. The complexes are of the compositions Ln2(NPNO)15 (ClO4)6 (Ln = La, Pr, Nd and Gd), Tb(NPNO), (C1O4)6), Ln2(NPNO)13 (C1O4)6) (Ln = Dy, Ho, and Yb); Ln (CPNO)8 (C104)3) (Ln = La, Pr, Nd, Tb, Dy, Ho and Yb) and Ln(CPNO), (C1O4)3) (Ln = Sm and Gd). Conductivity and IR data provide evidence for the non-coordinated nature of the perchlorate groups. IR and NMR spectra suggest coordinationvia the oxygen of the N-oxide group. Electronic spectral shapes of the Nd+3 and Ho+3 complexes are interpreted in terms of eight-and seven-coordinate environments in the case of 4-NPNO complexes and eight-coordination in the case of 4-CPNO complexes. IR data indicate bridged structure in NPNO complexes of lanthanides other than Tb.

Complexes of lanthanide perchlorates with N,N,N′,N′-tetramethyl-α-carboxamido-O-anisamide and N,N′-di-t-butyl-α-carboxamido-O-anisamide

A survey of the literature on lanthanide coordination compounds reveals that ligands involving ether oxygens as donor atoms have received very little attention [ 11. Only recently have the complexes of lanthanides with cyclic polyethers been characterized [l-3]. We report in this communication that interaction of rareearth perchlorates with two new ligands namely N,N,N’,N’-tetramethyl-u-carboxamido-Oanisamide (TMCA) and N,N’-di-t-butyl-crcarboxamido- 0-anisamide (DTBCA). The two ligands are potentially tridentate possessing two amide moieties and an ether linkage in between. The isolated complexes have been characterized by analysis, electrolytic conductance, infrared and electronic spectra. The ‘H and “C NMR spectra for the diamagnetic La3+ and Y3+ complexes are also discussed.

Lanthanide perchlorate complexes of picolinamide-N-oxide and 4-chloro pyridine 2-aldoxime-N-oxide

Abstract is not available.

Spectroscopic investigations and luminescence spectra of Nd3+ and Dy3+ doped different phosphate glasses

Spectral properties of Nd3+ and Dy3+ ions in different phosphate glasses were studied and several spectroscopic parameters were reported. Covalency of rare-earth-oxygen bond was studied in these phosphate glass matrices with the variation of modifier in host glass matrix Using Judd-Ofelt intensity parameters (Omega(2), Omega(4) and Omega(6)), radiative transition probabilities (A) and radiative lifetimes (tau(R)) of certain excited states of Nd3+ and Dy3+ ions are estimated in these glass matrices. From the magnitudes of branching ratios (beta(R)) and integrated absorption cross-sections (Sigma), certain transitions of both the ions are identified for laser excitation. From the emission spectra, peak stimulated emission cross-sections (sigma(P)) are evaluated for the emission transitions observed in all these phosphate glass matrices for both Nd3+ and Dy3+ ions. (C) 2009 Elsevier B.V. All rights reserved.