19423-88-2Relevant articles and documents
Synthesis, structure, thermal and luminescent behaviors of lanthanide-Pyridine-3,5-dicarboxylate frameworks series
?yszczek, Renata
, p. 120 - 127 (2011/01/08)
The isostructural series of lanthanide pyridine-3,5-dicarboxylates of the formula [Ln2pdc3(dmf)2]·(dmf) x(H2O)y where Ln are lanthanides from La(III) to Lu(III); pdc2--C5/s
Coordination polymers based on inorganic lanthanide(III) sulfate skeletons and an organic isonicotinate N-oxide connector: Segregation into three structural types by the lanthanide contraction effect
He, Zheng,Gao, En-Qing,Wang, Zhe-Ming,Yan, Chun-Hua,Kurmoo, Mohamedally
, p. 862 - 874 (2008/10/09)
Fourteen three-dimensional coordination polymers of general formula [Ln(INO)(H2O)(SO4)]n, where Ln = La, 1·La; Ce, 2·Ce; Pr, 3·Pr; Nd, 4·Nd; Sm, 5·Sm; Eu, 6·Eu; Gd, 7·Gd; Tb, 8·Tb; Dy, 9·Dy; Ho, 10·Ho; Er, 11·Er; Tm, 12·Tm; Yb, 13·Yb; and Lu, 14·Lu; INO = isonicotinate-N-oxide, have been synthesized by hydrothermal reactions of Ln3+, MnCO3, MnSO4·H 2O, and isonicotinic acid N-oxide (HINO) at 155 °C and characterized by single-crystal X-ray diffraction, IR, thermal analysis, luminescence spectroscopy, and the magnetic measurement. The structures are formed by connection of layer, chain, or dimer of Ln-SO4 by the organic connector, INO. They belong to three structural types that are governed exclusively by the size of the ions: type I for the large ions, La, Ce, and Pr; type II for the medium ions, Nd, Sm, Eu, Gd, and Tb; and type III for the small ions, Dy, Ho, Er, Tm, Yb, and Lu. Type I consists of two-dimensional undulate Ln-sulfate layers pillared by INO to form a three-dimensional network. Type II has a 2-fold interpenetration of 3D herringbone networks, in which the catenation is sustained by extensive π-π interactions and O-H...O and C-H...O hydrogen bonds. Type III comprises one-dimensional chains that are connected by INO bridges, resulting in an α-Po network. The progressive structural change is due to the metal coordination number decreasing from nine for the large ions via eight to seven for the small ions, demonstrating clearly the effect of lanthanide contraction. The sulfate ion acts as a μ4- or μ3-bridge, connecting two, three, or four metals, and is both mono- and bidentate. The INO ligand acts as a μ3- or μ2-bridge with carboxylate group in syn-syn bridging or bidentate chelating mode. The materials show considerably high thermal stability. The magnetic properties of 4·Nd, 6·Eu, 7·Gd, and 13·Yb and the luminescence properties of 6·Eu and 8·Tb are also investigated.
Solution enthalpies of hydrates LnCl3·xH2O (Ln=Ce-Lu)
Seifert,Funke
, p. 1 - 7 (2008/10/09)
Trichlorides of the lanthanide elements Ln=Ce-Lu form: (a) isotypic hexahydrates LnCl3·6H2O with a coordination number (CN) 8 for the Ln3+ ions. (b) Two isotypic groups of trihydrates LnCl3·3H2O, in the first group Ln=Ce-Dy the CN is 8; the structure of the second group Ln=Er-Lu is unknown. With Ho no trihydrate exists; a dihydrate is formed. (c) Two isotypic groups of monohydrates LnCl3·H2O with unknown structure - Ln=Ce-Dy and Ln=Ho-Lu. For all compounds and for anhydrous chlorides LnCl3 solution enthalpies were measured with an isoperibolic calorimeter. The ΔsolH0 values do not depend only on the difference (lattice enthalpies/hydration enthalpies), but also on the state in solution. According to Spedding the CN of the Ln3+ ions against water changes from 9 to 8 between Nd and Sm, causing minima in the series of solution enthalpies. Dihydrates LnCl3·2H2O are found for Ln=Ce, Pr, Nd, Sm and presumably for Eu and Gd. They are not yet well characterised.
