Structural Variety in Solvated Lanthanoid(III ) Halide Complexes

2000 ◽  
Vol 53 (10) ◽  
pp. 853 ◽  
Author(s):  
Glen B. Deacon ◽  
Tiecheng Feng ◽  
Peter C. Junk ◽  
Gerd Meyer ◽  
Natalie M. Scott ◽  
...  
Keyword(s):  
Far Infrared ◽  
Ionic Structure ◽  
X Ray ◽  
Structural Variety ◽  
Counter Ions ◽  
Halide Complexes ◽  
Monomeric Structure ◽  
Lanthanum Cation ◽  
Trigonal Prismatic ◽  
Infrared Data

Treatment of lanthanum metal with CH2Br2 or CH2I2 in tetrahydrofuran (thf) under ultrasound conditions yields the corresponding [LaX3(thf)4] (X = Br, I) complexes in good yield. Recrystallization of [LaBr3(thf)4] from 1,2-dimethoxyethane (dme) or bis(2-methoxyethyl) ether (diglyme) generates [LaBr2(µ-Br)(dme)2]2 and [LaBr2(dig-lyme)2][LaBr4(diglyme)]. Treatment of lanthanoid metals with hexachloroethane in dme yields [LnCl3(dme)2] (Ln = La, Nd, Er or Yb) and in acetonitrile [YbCl2(MeCN)5]2[YbCl3(MeCN)(-Cl)2YbCl3(MeCN)]. The reaction of Yb metal pieces with 1,2-dibromoethane in thf and dme gave single crystals of [YbBr3(thf)3] and [YbBr3(dme)2], respectively. The X-ray determined structure of [LaBr3(thf)4] shows a seven-coordinate monomer with pentagonal-bipyramidal stereochemistry and apical bromide ligands. For [YbBr3(thf)3], a monomeric structure with mer-octa-hedral stereochemistry is observed. In [LaBr2(µ-Br)(dme)2]2, two eight-coordinate La centres are linked by two bridging bromides. The dme ligands have a trans relationship to each other, and cis terminal bromides are transoid to the bridging bromides with dodecahedral stereochemistry for La. By contrast, the 1: 1.5 diglyme adduct is found to be ionic [LaBr2(diglyme)2][LaBr4(diglyme)], with an eight-coordinate bicapped trigonal-prismatic lanthanum cation and a seven-coordinate pentagonal-bipyramidal lanthanum anion. In the cation, the bromide ligands are cis to each other, and in the anion, two bromides are equatorial and two are axial. In [YbBr3(dme)2], [YbCl3(dme)2] and [ErCl3(dme)2], a seven-coordinate pentagonal-bipyramidal arrangement exists with apical halogen ligands. Far-infrared data, and in particular the absence of absorptions attributable to Ì(La–Clter), suggest that [LaCl3(dme)] is polymeric with six bridging chlorides per lanthanum. For [YbCl2(MeCN)5]2[YbCl3(MeCN)(-Cl)2YbCl3-(MeCN)], a remarkable ionic structure, with pentagonal-bipyramidal [YbCl2(MeCN)5]+ cations and octahedral di-nuclear [YbCl3(MeCN)(-Cl)2YbCl3(MeCN)]2– counter ions, is observed. In the former, chloride ligands are apical, while the MeCN ligands of the latter are transoid.

Synthesis and Characterization of Gold(III) Halide Complexes of Quinaldic Acid (Hqd), Methyl Quinaldate and Ethyl Quinaldate, and X-Ray Structure of [(HQd)2H] [AuBr4].H2O

1994 ◽  
Vol 47 (7) ◽  
pp. 1423 ◽  
Author(s):  
MAS Goher ◽  
AK Hafez ◽  
RJ Wang ◽  
XM Chen ◽  
TCW Mak
Keyword(s):  
Hydrogen Bond ◽  
Far Infrared ◽  
Synthesis And Characterization ◽  
Coordination Environment ◽  
X Ray ◽  
Quinaldic Acid ◽  
Halide Complexes ◽  
Monodentate Ligands ◽  
Far Infrared Spectra

Complexes of the types HAuX4.2HQd, where X = Cl or Br and HQd = quinaldic acid, and AuX3L2, where L is methyl or ethyl quinaldate , have been prepared and characterized. Quinaldic acid as well as methyl and ethyl quinaldates function as monodentate ligands in these complexes, whose stereochemistries are discussed in relation to the number of gold-halogen stretching frequencies observed in their far-infrared spectra. The measured conductivities of these complexes are also discussed. Single-crystal X-ray analysis of monohydrated HAuBr4.2HQd revealed that it should be formulated as [( HQd )2H][AuBr4].H2O, in which a pair of zwitterionic HQd moieties are connected by a strong O...H...O hydrogen bond, and the gold(III) atom is in an elongated octahedral coordination environment with two long Au-O bonds of 3.388(8) and 3.440(8)Ǻ.

scholarly journals Incorporating Far-Infrared Data into Carbonate Mineral Analyses

Minerals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 628
Author(s):  
Stephen Campbell ◽  
Kristin M. Poduska
Keyword(s):  
Far Infrared ◽  
Carbonate Mineral ◽  
X Ray Diffraction ◽  
Mid Infrared ◽  
X Ray ◽  
Peak Overlap ◽  
Spectral Changes ◽  
Mineral Analyses ◽  
Fir Spectra ◽  
Infrared Data

Polycrystalline carbonate minerals (including calcite, Mg-calcite, and aragonite) can show distinctive variations in their far-infrared (FIR) spectra. We describe how to identify mixed-phase samples by correlating FIR spectral changes with mid-infrared spectra, X-ray diffraction data, and simple peak overlap simulations. Furthermore, we show how to distinguish portlandite-containing (Ca(OH) 2 ) mixtures that are common in heated calcium carbonate samples. Ultimately, these results could be used for tracking how minerals are formed and how they change during environmental exposure or processing after extraction.

Synthetic and Structural Studies in the Lanthanide Toluene-4-sulfonate Hydrates

1992 ◽  
Vol 45 (3) ◽  
pp. 583 ◽  
Author(s):  
DL Faithfull ◽  
JM Harrowfield ◽  
MI Ogden ◽  
BW Skelton ◽  
K Third ◽  
...  
Keyword(s):  
Water Molecules ◽  
Space Group ◽  
X Ray ◽  
Lattice Water ◽  
Lanthanide Elements ◽  
Counter Ions ◽  
Dehydration Reactions ◽  
Structure Determinations ◽  
Contemporary Work ◽  
Trigonal Prismatic

Single-crystal X-ray structure determinations at c. 295 K are reported for representative members of the hydrated toluene-4-sulfonates of the lanthanide elements. The early members of the series, represented by lanthanum, cerium and neodymium, are monoclinic tridecahydrates , space group C2/c, a ≈ 32, b ≈ 7.2, c ≈ 35 �, β ≈ 115 �, Z = 8; the cation is a tricapped trigonal prismatic nonaaqualanthanide (III) species, with three toluene-4-sulfonate counter ions and four lattice water molecules per formula/asymmetric unit. The later members of the series, represented by samarium, lutetium and also yttrium, are, in agreement with contemporary work, monoclinic nonahydrates , space group P21/n, a ≈ 25, b ≈ 7.5, c ≈ 17.8 � , β ≈ 99�, Z = 4; the cation is a square prismatic hexaaquabis (toluene-4-sulfonato)lanthanide(III) species with a single toluene-4-sulfonate counter ion and three lattice water molecules. The solid state dehydration reactions of the tridecahydrates are complicated but there is at least one more endothermic step than is observed for the nonahydrates , with both series of compounds appearing to undergo water loss only below 300�C.

Structure and Spectroscopic Studies of Cd(II) Complexes of Tris(2-pyridyl)amine: 1D and 2D Supramolecular Assemblies

2003 ◽  
Vol 68 (11) ◽  
pp. 2139-2149 ◽  
Author(s):  
Yong-Shu Xie ◽  
Xue-Ting Liu ◽  
Jia-Xiang Yang ◽  
Hui Jiang ◽  
Qing-Liang Liu ◽  
...  
Keyword(s):  
Spectroscopic Data ◽  
Far Infrared ◽  
Spectroscopic Studies ◽  
X Ray Diffraction ◽  
Absorption Bands ◽  
X Ray ◽  
Halide Complexes ◽  
2D Network ◽  
Far Infrared Spectra ◽  
Dinuclear Structure

Cd(II) halide complexes [Cd2X4(tpa)2] (1: X = Cl, 2: X = Br, 3: X = I; tpa = tris(2-pyridyl)amine) have been synthesized. X-Ray diffraction analyses of 2 and 3 reveal their asymmetrical dinuclear structures: one Cd(II) atom is octahedrally coordinated to four N atoms of two tpa ligands and two bridging halides; the other Cd(II) is tetrahedrally coordinated to two terminal (X(t)) and two bridging (X(b)) halides. By multiple intra- and intermolecular π-π interactions between the tpa pyridine rings, the ligands of 2 and 3 are linked to form a 2D network and 1D linear structures, respectively. In the Raman and far-infrared spectra, the absorption bands due to Cd-X(b) stretching modes lie at lower wavenumbers compared to the Cd-X(t) stretches. It can be inferred from the spectroscopic data that 1 has a dinuclear structure similar to those of 2 and 3.

Tracing young SMBHs in the dusty distant universe – a Chandra view of DOGs

2020 ◽  
Vol 15 (S359) ◽  
pp. 17-21
Author(s):  
Karín Menéndez-Delmestre ◽  
Laurie Riguccini ◽  
Ezequiel Treister
Keyword(s):  
Star Formation ◽  
Main Sequence ◽  
Far Infrared ◽  
Host Galaxy ◽  
X Ray ◽  
Star Forming ◽  
Near Ir ◽  
X Ray Imaging ◽  
Combined Use ◽  
Dusty Galaxies

AbstractThe coexistence of star formation and AGN activity has geared much attention to dusty galaxies at high redshifts, in the interest of understanding the origin of the Magorrian relation observed locally, where the mass of the stellar bulk in a galaxy appears to be tied to the mass of the underlying supermassive black hole. We exploit the combined use of far-infrared (IR) Herschel data and deep Chandra ˜160 ksec depth X-ray imaging of the COSMOS field to probe for AGN signatures in a large sample of >100 Dust-Obscured Galaxies (DOGs). Only a handful (˜20%) present individual X-ray detections pointing to the presence of significant AGN activity, while X-ray stacking analysis on the X-ray undetected DOGs points to a mix between AGN activity and star formation. Together, they are typically found on the main sequence of star-forming galaxies or below it, suggesting that they are either still undergoing significant build up of the stellar bulk or have started quenching. We find only ˜30% (6) Compton-thick AGN candidates (NH > 1024 cm–2), which is the same frequency found within other soft- and hard-X-ray selected AGN populations. This suggests that the large column densities responsible for the obscuration in Compton-thick AGNs must be nuclear and have little to do with the dust obscuration of the host galaxy. We find that DOGs identified to have an AGN share similar near-IR and mid-to-far-IR colors, independently of whether they are individually detected or not in the X-ray. The main difference between the X-ray detected and the X-ray undetected populations appears to be in their redshift distributions, with the X-ray undetected ones being typically found at larger distances. This strongly underlines the critical need for multiwavelength studies in order to obtain a more complete census of the obscured AGN population out to higher redshifts. For more details, we refer the reader to Riguccini et al. (2019).

Cobalt(II) Mercury Tetrathiocyanate Complexes with Lewis Bases

1973 ◽  
Vol 51 (3) ◽  
pp. 438-447 ◽  
Author(s):  
R. Makhija ◽  
L. Pazdernik ◽  
R. Rivest
Keyword(s):  
Magnetic Susceptibility ◽  
Powder Diffraction ◽  
Elemental Analysis ◽  
Far Infrared ◽  
Crystalline Solid ◽  
Ultraviolet Spectroscopy ◽  
X Ray ◽  
Lewis Bases ◽  
Polydentate Ligands

A new series of octahedral cobalt(II) complexes are formed when CoX2(X = Cl, Br, I, SCN) reacts with Hg(SCN)2 in the presence of Lewis bases. These complexes of stoichiometry CoHg(SCN)4•2L (L = THF, dioxane, pyridine, aniline) are pink to violet solids which slowly decompose to the blue crystalline solid, CoHg(SCN)4, the stable magnetic susceptibility standard. On further reaction of CoHg(SCN)4•2THF with mono-, bi-, and polydentate ligands in dry ethanol, complexes of the following types are obtained: CoHg(SCN)4•2L (L = PΦ3), CoHg(SCN)4•2LL (LL = trien), CoHg(SCN)4•3LL (LL = en, bipy), and CoHg(SCN)4•4LL (LL = phen). The stoichiometry of these were determined by elemental analysis. Possible structures of these are discussed with the help of mid and far infrared, visible, and ultraviolet spectroscopy, magnetic susceptibility, and X-ray powder diffraction. Some new i.r. bands like Co—P, Co—N, and Hg—S are assigned in the low region.

Radiation Production Using Femtosecond Electron Bunches

2005 ◽  
Vol 107 ◽  
pp. 11-14
Author(s):  
C. Thongbai ◽  
V. Jinamoon ◽  
N. Kangrang ◽  
K. Kusoljariyakul ◽  
S. Rimjaem ◽  
...  
Keyword(s):  
Far Infrared ◽  
Bunch Length ◽  
X Rays ◽  
Research Facility ◽  
X Ray ◽  
Electron Bunches ◽  
Rf Gun ◽  
Intense Radiation ◽  
Far Infrared Radiation ◽  
Femtosecond Electron Bunches

Femtosecond electron bunches can be generated from a system consisting of an RF gun with a thermionic cathode, an alpha magnet, and a linear accelerator and can be used to produce femtosecond (fs) electromagnetic radiation pulses. At the Fast Neutron Research Facility (FNRF), Thailand, we are especially interested in production in Far-infrared (FIR) and x-radiation. In the far-infrared, radiation is emitted coherently for wavelengths which are longer than the electron bunch length, yielding intense radiation. Although, the x-rays emitted are incoherent, its femtosecond time scale is crucial for development of a femtosecond x-ray source.

Grating groove metrology and efficiency predictions from the soft x-ray to the far infrared

2002 ◽  
Author(s):  
David A. Content ◽  
Petar Arsenovic ◽  
Ivan G. Kuznetsov ◽  
Theo Hadjimichael
Keyword(s):  
Far Infrared ◽  
X Ray

scholarly journals The Far‐Infrared Spectral Energy Distributions of X‐Ray–selected Active Galaxies

2003 ◽  
Vol 590 (1) ◽  
pp. 128-148 ◽  
Author(s):  
Joanna K. Kuraszkiewicz ◽  
Belinda J. Wilkes ◽  
Eric ◽  
J. Hooper ◽  
Kim K. McLeod ◽  
...  
Keyword(s):  
Far Infrared ◽  
Active Galaxies ◽  
Spectral Energy ◽  
Spectral Energy Distributions ◽  
Energy Distributions ◽  
X Ray ◽  
Infrared Spectral
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