scholarly journals Comparison of tetravalent cerium and terbium ions in a conserved, homoleptic imidophosphorane ligand field

2020 ◽  
Vol 11 (24) ◽  
pp. 6149-6159 ◽  
Author(s):  
Natalie T. Rice ◽  
Ivan A. Popov ◽  
Dominic R. Russo ◽  
Thaige P. Gompa ◽  
Arun Ramanathan ◽  
...  
Keyword(s):  
Spectroscopic Analysis ◽  
Lanthanide Ions ◽  
Ligand Field ◽  
Redox Pair ◽  
Tetravalent Cerium

A redox pair of Ce4+ and Ce3+ complexes, isotypic to previously prepared Tb4+ and Tb3+ complexes, respectively, is reported to establish a comparative physical and spectroscopic analysis of tetravalent lanthanide ions.

Complexes of Light Lanthanides with 3,4-Dimethoxybenzoic Acid

2000 ◽  
Vol 65 (2) ◽  
pp. 179-191 ◽  
Author(s):  
Wiesława Ferenc ◽  
Agnieszka Walków-Dziewulska
Keyword(s):  
Magnetic Moments ◽  
Intermediate Formation ◽  
Lanthanide Ions ◽  
Ligand Field ◽  
X Ray Diffraction ◽  
Magnetic Studies ◽  
X Ray ◽  
Light Lanthanides ◽  
Polycrystalline Solids ◽  
Van Vleck

The complexes of light lanthanides with 3,4-dimethoxybenzoic acid, Ln(C9H9O4)3·4 H2O, where Ln = La(III), Ce(III), Pr(III), Nd(III), Sm(III), Eu(III) and Gd(III), have been synthesized as polycrystalline solids and characterized by elemental analysis, IR spectroscopy, thermogravimetric and magnetic studies and X-ray diffraction measurements. The complexes possess colours typical of Ln(III) ions (La, Ce, Eu, Gd white, Pr greenish, Nd violet and Sm cream). The carboxylate group in these complexes binds as a symmetrical, bidentate chelating ligand. On heating in air to 1 273 K the 3,4-dimethoxybenzoates of Ce(III), Pr(III), Sm(III), Eu(III) and Gd(III) first dehydrate to anhydrous salts that further decompose to oxides of the respective metals. The 3,4-dimethoxybenzoates of La(III) and Nd(III) decompose in three steps. Firstly, they dehydrate to anhydrous salts that further decompose to the oxides with the intermediate formation of oxycarbonates. The solubilities of the studied complexes in water at 293 K is in the order of 10-4-10-3 mol dm-3. Their magnetic moments were determined in the temperature range 77-298 K and found to obey the Curie-Weiss law. The values of μeff calculated for the all compounds (except that for Eu) are close to those obtained for Ln(III) by Hund and van Vleck. The results show that there is no influence of the ligand field on 4f electrons of the lanthanide ions in these polycrystalline compounds; 4f electrons probably do not participate in the formation of the Ln-O bonds.

scholarly journals Design, Isolation, and Spectroscopic Analysis of a Tetravalent Terbium Complex

2019 ◽  
Author(s):  
Natalie Rice ◽  
Ivan Popov ◽  
Dominic Russo ◽  
John Bacsa ◽  
Enrique Batista ◽  
...  
Keyword(s):  
Ground State ◽  
Molecular Complexes ◽  
Lanthanide Ions ◽  
Ligand Field ◽  
Zero Field ◽  
High Symmetry ◽  
Zero Field Splitting ◽  
Terbium Complex ◽  
Field Splitting ◽  
Metal Ligand

Synthetic strategies to yield molecular complexes of high-valent lanthanides, other than the ubiquitous Ce<sup>4+</sup> ion, are exceptionally rare, and thorough, detailed characterization in these systems is limited by complex lifetime and reaction and isolation conditions. The synthesis of high-symmetry complexes in high purity with significant lifetimes in solution and solid-state are essential for determining the role of ligand-field splitting, multiconfigurational behavior, and covalency in governing the reactivity and physical properties of these potentially technologically transformative tetravalent ions. We report the synthesis and physical characterization of an <i>S</i><sub>4</sub> symmetric, four-coordinate tetravalent terbium complex, [Tb(NP(1,2-bis-<i><sup>t</sup></i>Bu-diamidoethane)(NEt<sub>2</sub>))<sub>4</sub>] (where Et is ethyl and <i>t</i>Bu is <i>tert</i>-butyl). The ligand field in this complex is weak and the metal-ligand bonds sufficiently covalent so that the tetravalent terbium ion is stable and accessible via a mild oxidant from the anionic, trivalent, terbium precursor, [(Et<sub>2</sub>O)K][Tb(NP(1,2-bis-<i><sup>t</sup></i>Bu-diamidoethane)(NEt<sub>2</sub>))<sub>4</sub>]. The significant stability of the tetravalent complex enables its thorough characterization. The step-wise development of the supporting ligand points to key ligand control elements for further extending the known tetravalent lanthanide ions in molecular complexes. Magnetic susceptibility, electron paramagnetic resonance (EPR) spectroscopy, X-ray absorption near-edge spectroscopy (XAS), and density functional theory studies indicate a <i>4f<sup>7</sup></i> ground state for [Tb(NP(1,2-bis-<i><sup>t</sup></i>Bu-diamidoethane)(NEt<sub>2</sub>))<sub>4</sub>] with considerable zero-field splitting: demonstrating that magnetic, tetravalent lanthanide ions engage in covalent metal-ligand bonds. This result has significant implications for the use of tetravalent lanthanide ions in magnetic applications since the observed zero-field splitting is intermediate between that observed for the trivalent lanthanides and for the transition metals. The similarity of the multiconfigurational behavior in the ground state of [Tb(NP(1,2-bis-<i><sup>t</sup></i>Bu-diamidoethane)(NEt<sub>2</sub>))<sub>4</sub>] (measured by Tb L<sub>3</sub>-edge XAS) to that observed in TbO<sub>2</sub> implicates ligand control of multiconfigurational behavior as a key component of the stability of the complex.

Pentanuclear lanthanide pyramids based on thiacalix[4]arene ligand exhibiting slow magnetic relaxation

2015 ◽  
Vol 44 (35) ◽  
pp. 15481-15490 ◽  
Author(s):  
Jing-Yuan Ge ◽  
Jing Ru ◽  
Feng Gao ◽  
You Song ◽  
Xin-Hui Zhou ◽  
...  
Keyword(s):  
Magnetic Relaxation ◽  
Lanthanide Ions ◽  
Ligand Field ◽  
Molecular Symmetry ◽  
Slow Magnetic Relaxation ◽  
Arene Ligand ◽  
First Time

Six pentanuclear LnIII clusters have been isolated based on thiacalix[4]arene ligand for the first time. Two Dy5 clusters feature distinct slow magnetic relaxation, which is affected presumably by the ligand, field molecular symmetry and coordination geometries of lanthanide ions.

scholarly journals Design, Isolation, and Spectroscopic Analysis of a Tetravalent Terbium Complex

2019 ◽  
Author(s):  
Natalie Rice ◽  
Ivan Popov ◽  
Dominic Russo ◽  
John Bacsa ◽  
Enrique Batista ◽  
...  
Keyword(s):  
Ground State ◽  
Molecular Complexes ◽  
Lanthanide Ions ◽  
Ligand Field ◽  
Zero Field ◽  
High Symmetry ◽  
Zero Field Splitting ◽  
Terbium Complex ◽  
Field Splitting ◽  
Metal Ligand

Synthetic strategies to yield molecular complexes of high-valent lanthanides, other than the ubiquitous Ce<sup>4+</sup> ion, are exceptionally rare, and thorough, detailed characterization in these systems is limited by complex lifetime and reaction and isolation conditions. The synthesis of high-symmetry complexes in high purity with significant lifetimes in solution and solid-state are essential for determining the role of ligand-field splitting, multiconfigurational behavior, and covalency in governing the reactivity and physical properties of these potentially technologically transformative tetravalent ions. We report the synthesis and physical characterization of an <i>S</i><sub>4</sub> symmetric, four-coordinate tetravalent terbium complex, [Tb(NP(1,2-bis-<i><sup>t</sup></i>Bu-diamidoethane)(NEt<sub>2</sub>))<sub>4</sub>] (where Et is ethyl and <i>t</i>Bu is <i>tert</i>-butyl). The ligand field in this complex is weak and the metal-ligand bonds sufficiently covalent so that the tetravalent terbium ion is stable and accessible via a mild oxidant from the anionic, trivalent, terbium precursor, [(Et<sub>2</sub>O)K][Tb(NP(1,2-bis-<i><sup>t</sup></i>Bu-diamidoethane)(NEt<sub>2</sub>))<sub>4</sub>]. The significant stability of the tetravalent complex enables its thorough characterization. The step-wise development of the supporting ligand points to key ligand control elements for further extending the known tetravalent lanthanide ions in molecular complexes. Magnetic susceptibility, electron paramagnetic resonance (EPR) spectroscopy, X-ray absorption near-edge spectroscopy (XAS), and density functional theory studies indicate a <i>4f<sup>7</sup></i> ground state for [Tb(NP(1,2-bis-<i><sup>t</sup></i>Bu-diamidoethane)(NEt<sub>2</sub>))<sub>4</sub>] with considerable zero-field splitting: demonstrating that magnetic, tetravalent lanthanide ions engage in covalent metal-ligand bonds. This result has significant implications for the use of tetravalent lanthanide ions in magnetic applications since the observed zero-field splitting is intermediate between that observed for the trivalent lanthanides and for the transition metals. The similarity of the multiconfigurational behavior in the ground state of [Tb(NP(1,2-bis-<i><sup>t</sup></i>Bu-diamidoethane)(NEt<sub>2</sub>))<sub>4</sub>] (measured by Tb L<sub>3</sub>-edge XAS) to that observed in TbO<sub>2</sub> implicates ligand control of multiconfigurational behavior as a key component of the stability of the complex.

scholarly journals Magnetic and Luminescent Properties of Isostructural 2D Coordination Polymers Based on 2-Pyrimidinecarboxylate and Lanthanide Ions

Crystals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 571
Author(s):  
Amalia García-García ◽  
Andoni Zabala-Lekuona ◽  
Ainhoa Goñi-Cárdenas ◽  
Javier Cepeda ◽  
José M. Seco ◽  
...  
Keyword(s):  
Coordination Polymers ◽  
Single Molecule ◽  
Density Functional ◽  
Magnetic Measurements ◽  
Luminescent Properties ◽  
Rare Earth Ions ◽  
Lanthanide Ions ◽  
Ligand Field ◽  
Bridging Ligands ◽  
Metal Centers

A couple of isostructural coordination polymers with the general formula [Ln4(pymca)4(AcO)8]n have been obtained from reactions between pyrimidine-2-carboxylate (pymca) ligand and rare-earth ions (Ln = Dy (1), Nd (2)). These two-dimensional compounds have been characterized and the crystal structures have been solved by single-crystal X-ray diffraction technique, resulting in layers along the bc plane based on pymca and acetate anions that act as bridging ligands between metal atoms. Given that pymca and acetate anions possess carboxylate and hetero-nitrogen groups, it is possible to build a coordination polymer whose metal centers have a nine coordination. Furthermore, static and dynamic magnetic measurements of compound 1 reveal the lack of single molecule-magnet (SMM) behavior in this system due to the following two effects: (i) the ligand field does not stabilize magnetic ground states well separated from excited states, and (ii) anisotropy axes are not collinear, according to results with Magellan software. On another level, luminescent properties of compounds 1 and 2 are attributed to singlet π-π* transitions centered on pymca ligand as corroborated by time-dependent density functional theory (TD-DFT) calculations.

Characterization of Chemical Impurities in Glutaraldehyde

1975 ◽  
Vol 33 ◽  
pp. 620-621
Author(s):  
B. J. Grenon ◽  
A. J. Tousimis
Keyword(s):  
Glutaric Acid ◽  
Spectroscopic Analysis ◽  
Aldol Condensation ◽  
Condensation Product ◽  
Amorphous Solid ◽  
Water Soluble ◽  
Impurity Component ◽  
Chemical Impurities ◽  
Soluble Liquid

Ever since the introduction of glutaraldehyde as a fixative in electron microscopy of biological specimens, the identification of impurities and consequently their effects on biologic ultrastructure have been under investigation. Several reports postulate that the impurities of glutaraldehyde, used as a fixative, are glutaric acid, glutaraldehyde polymer, acrolein and glutaraldoxime.Analysis of commercially available biological or technical grade glutaraldehyde revealed two major impurity components, none of which has been reported. The first compound is a colorless, water-soluble liquid with a boiling point of 42°C at 16 mm. Utilizing Nuclear Magnetic Resonance (NMR) spectroscopic analysis, this compound has been identified to be — dihydro-2-ethoxy 2H-pyran. This impurity component of the glutaraldehyde biological or technical grades has an UV absorption peak at 235nm. The second compound is a white amorphous solid which is insoluble in water and has a melting point of 80-82°C. Initial chemical analysis indicates that this compound is an aldol condensation product(s) of glutaraldehyde.

Elemental analysis of human erythrocytes

1989 ◽  
Vol 47 ◽  
pp. 242-243
Author(s):  
S. A. Livesey ◽  
A. A. del Campo ◽  
E. S. Griffey ◽  
D. Ohlmer ◽  
T. Schifani ◽  
...  
Keyword(s):  
Sample Preparation ◽  
Elemental Analysis ◽  
Human Erythrocyte ◽  
Spectroscopic Analysis ◽  
Model System ◽  
Human Erythrocytes ◽  
List Type ◽  
Chemical Fixation ◽  
Ethanol Dehydration ◽  
Lowicryl K4m

The aim of this study is to compare methods of sample preparation for elemental analysis. The model system which is used is the human erythrocyte. Energy dispersive spectroscopic analysis has been previously reported for cryofixed and cryosectioned erythrocytes. Such work represents the reference point for this study. The use of plastic embedded samples for elemental analysis has also been documented. The work which is presented here is based on human erythrocytes which have been either chemically fixed and embedded or cryofixed and subsequently processed by a variety of techniques which culminated in plastic embedded samples.Heparinized and washed erythrocytes were prepared by the following methods for this study :(1). Chemical fixation in 4% paraformaldehyde/0.25% glutaraldehyde/0.2 M sucrose in 0.1 M Na cacodylate, pH 7.3 for 30 min, followed by ethanol dehydration, infiltration and embedding in Lowicryl K4M at -20° C.

Ligand Field Studies on the Reinecke-Type Complexes with Aniline and Benzylamine

1971 ◽  
Vol 74 (1_2) ◽  
pp. 11-16 ◽  
Author(s):  
I. Gănescu ◽  
Margareta Teodorescu ◽  
C. I. Lepădatu
Keyword(s):  
Field Studies ◽  
Ligand Field

Chromatographic and spectroscopic analysis of the fluorescent compounds derived from monosaccharides on HPTLC-NH2plates

2002 ◽  
Vol 15 (6) ◽  
pp. 449-453 ◽  
Author(s):  
G. Grygierczyk ◽  
Walter Fischer ◽  
M. Sajewicz ◽  
P. Kuś ◽  
R. Wrzalik ◽  
...  
Keyword(s):  
Spectroscopic Analysis ◽  
Fluorescent Compounds

Hydrothermal Synthesis and Solid-State Laser Refrigeration of Ytterbium-Doped Potassium Lutetium Fluoride (KLF) Microcrystals

2020 ◽  
Author(s):  
Xiaojing Xia ◽  
Anupum Pant ◽  
Xuezhe Zhou ◽  
Elena Dobretsova ◽  
Alex Bard ◽  
...  
Keyword(s):  
Hydrothermal Synthesis ◽  
Solid State ◽  
Information Science ◽  
Point Group ◽  
Solid State Laser ◽  
Lanthanide Ions ◽  
Group Symmetry ◽  
Luminescence Spectra ◽  
Crystalline Phases ◽  
State Laser

Fluoride crystals, due to their low phonon energies, are attractive hosts of trivalent lanthanide ions for applications in upconverting phosphors, quantum information science, and solid-state laser refrigeration. In this article, we report the rapid, low-cost hydrothermal synthesis of potassium lutetium fluoride (KLF) microcrystals for applications in solid-state laser refrigeration. Four crystalline phases were synthesized, namely orthorhombic K<sub>2</sub>LuF<sub>5</sub> (Pnma), trigonal KLuF<sub>4</sub> (P3<sub>1</sub>21), orthorhombic KLu<sub>2</sub>F<sub>7</sub> (Pna2<sub>1</sub>), and cubic KLu<sub>3</sub>F<sub>10</sub> (Fm3m), with each phase exhibiting unique microcrystalline morphologies. Luminescence spectra and emission lifetimes of the four crystalline phases were characterized based on the point-group symmetry of trivalent cations. Laser refrigeration was measured by observing both the optomechanical eigenfrequencies of microcrystals on cantilevers in vacuum, and also the Brownian dynamics of optically trapped microcrystals in water. Among all four crystalline phases, the most significant cooling was observed for 10%Yb:KLuF<sub>4</sub> with cooling of 8.6 $\pm$ 2.1 K below room temperature. Reduced heating was observed with 10%Yb:K<sub>2</sub>LuF<sub>5</sub>

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