The Structure of Three-Coordinated Copper(II) Complexes and the Infrared C=O Stretching Vibration

1963 ◽  
Vol 16 (1) ◽  
pp. 7 ◽  
Author(s):  
M Kubo ◽  
M Kuroda ◽  
M Krishita ◽  
Y Muto
Keyword(s):  
Magnetic Moment ◽  
Magnetic Moments ◽  
Literal Sense ◽  
Binuclear Structure ◽  
Stretching Vibration ◽  
New Type ◽  
Stretching Vibrations

A new type of binuclear structure having copper atoms of ligancy 4 is proposed on the basis of infrared C=O stretching vibrations for the so-called three-coordinated copper(II) complexes showing a normal magnetic moment. In this binuclear structure, copper atoms are bridged in pairs by two Cu-O-C-O-Cu links of syn-anti arrangement. Suggestion is made that "three-coordinated" copper(II) complexes in the literal sense of the word do not exist regardless of whether the complexes show normal or subnormal magnetic moments.

Infrared spectra and substituent effects in 2-(3-, and 4-substituted phenylmethylene)-1,3-cycloheptanediones

1983 ◽  
Vol 48 (2) ◽  
pp. 586-595 ◽  
Author(s):  
Alexander Perjéssy ◽  
Pavol Hrnčiar ◽  
Ján Šraga
Keyword(s):  
Substituent Effects ◽  
Phenyl Group ◽  
Wave Number ◽  
Vibrational Coupling ◽  
Wave Numbers ◽  
Stretching Vibration ◽  
Stretching Vibrations ◽  
The Relationship ◽  
Derivatives Of ◽  
Effect Of Structure

The wave numbers of the fundamental C=O and C=C stretching vibrations, as well as that of the first overtone of C=O stretching vibration of 2-(3-, and 4-substituted phenylmethylene)-1,3-cycloheptanediones and 1,3-cycloheptanedione were measured in tetrachloromethane and chloroform. The spectral data were correlated with σ+ constants of substituents attached to phenyl group and with wave number shifts of the C=O stretching vibration of substituted acetophenones. The slope of the linear dependence ν vs ν+ of the C=C stretching vibration of the ethylenic group was found to be more than two times higher than that of the analogous correlation of the C=O stretching vibration. Positive values of anharmonicity for asymmetric C=O stretching vibration can be considered as an evidence of the vibrational coupling in a cyclic 1,3-dicarbonyl system similarly, as with derivatives of 1,3-indanedione. The relationship between the wave numbers of the symmetric and asymmetric C=O stretching vibrations indicates that the effect of structure upon both vibrations is symmetric. The vibrational coupling in 1,3-cycloheptanediones and the application of Seth-Paul-Van-Duyse equation is discussed in relation to analogous results obtained for other cyclic 1,3-dicarbonyl compounds.

scholarly journals Spin Gapless Semiconductor–Nonmagnetic Semiconductor Transitions in Fe-Doped Ti2CoSi: First-Principle Calculations

2018 ◽  
Vol 8 (11) ◽  
pp. 2200 ◽  
Author(s):  
Yu Feng ◽  
Zhou Cui ◽  
Ming-sheng Wei ◽  
Bo Wu ◽  
Sikander Azam
Keyword(s):  
Magnetic Moment ◽  
Electronic Structures ◽  
Magnetic Moments ◽  
Total Magnetic Moment ◽  
First Principle ◽  
Half Metallic ◽  
Heusler Compound ◽  
First Principle Calculations ◽  
Metallic Ferromagnet

Employing first-principle calculations, we investigated the influence of the impurity, Fe atom, on magnetism and electronic structures of Heusler compound Ti2CoSi, which is a spin gapless semiconductor (SGS). When the impurity, Fe atom, intervened, Ti2CoSi lost its SGS property. As TiA atoms (which locate at (0, 0, 0) site) are completely occupied by Fe, the compound converts to half-metallic ferromagnet (HMF) TiFeCoSi. During this SGS→HMF transition, the total magnetic moment linearly decreases as Fe concentration increases, following the Slate–Pauling rule well. When all Co atoms are substituted by Fe, the compound converts to nonmagnetic semiconductor Fe2TiSi. During this HMF→nonmagnetic semiconductor transition, when Fe concentration y ranges from y = 0.125 to y = 0.625, the magnetic moment of Fe atom is positive and linearly decreases, while those of impurity Fe and TiB (which locate at (0.25, 0.25, 0.25) site) are negative and linearly increase. When the impurity Fe concentration reaches up to y = 1, the magnetic moments of Ti, Fe, and Si return to zero, and the compound is a nonmagnetic semiconductor.

scholarly journals Origin of the Low Magnetic Moment in Fe2AlTi: An Ab Initio Study

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1732 ◽  
Author(s):  
Martin Friák ◽  
Anton Slávik ◽  
Ivana Miháliková ◽  
David Holec ◽  
Monika Všianská ◽  
...  
Keyword(s):  
Ab Initio ◽  
Magnetic Moment ◽  
Energy Surface ◽  
Magnetic Moments ◽  
Local Magnetic Moment ◽  
Spin Configuration ◽  
Spin Effects ◽  
Order Of Magnitude ◽  
Huge Impact ◽  
Insight Into

The intermetallic compound Fe 2 AlTi (alternatively Fe 2 TiAl) is an important phase in the ternary Fe-Al-Ti phase diagram. Previous theoretical studies showed a large discrepancy of approximately an order of magnitude between the ab initio computed magnetic moments and the experimentally measured ones. To unravel the source of this discrepancy, we analyze how various mechanisms present in realistic materials such as residual strain effects or deviations from stoichiometry affect magnetism. Since in spin-unconstrained calculations the system always evolves to the spin configuration which represents a local or global minimum in the total energy surface, finite temperature spin effects are not well described. We therefore turn the investigation around and use constrained spin calculations, fixing the global magnetic moment. This approach provides direct insight into local and global energy minima (reflecting metastable and stable spin phases) as well as the curvature of the energy surface, which correlates with the magnetic entropy and thus the magnetic configuration space accessible at finite temperatures. Based on this approach, we show that deviations from stoichiometry have a huge impact on the local magnetic moment and can explain the experimentally observed low magnetic moments.

scholarly journals Distinguishing Features and Identification Criteria for K-Dioctahedral 1M Micas (Illite-Aluminoceladonite and Illite-Glauconite-Celadonite Series) from Middle-Infrared Spectroscopy Data

Minerals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 153 ◽  
Author(s):  
Bella B. Zviagina ◽  
Victor A. Drits ◽  
Olga V. Dorzhieva
Keyword(s):  
Infrared Region ◽  
Spectroscopy Data ◽  
Unit Cell Parameters ◽  
Cation Composition ◽  
Cell Parameters ◽  
Sharp Maximum ◽  
Stretching Vibration ◽  
Stretching Vibrations ◽  
Middle Infrared ◽  
Distinguishing Features

A representative collection of K-dioctahedral 1M micas ranging in composition from (Mg, Fe)-poor illites to aluminoceladonites through Mg-rich illites (Fe-poor varieties) and from Fe-bearing, Mg-rich illites to celadonites through Fe-illites, Al-glauconites and glauconites (Fe-bearing varieties) was studied by Fourier-transform infrared (FTIR) spectroscopy in the middle-infrared region. Analysis and comparison of the relationships between the band positions and cation compositions of Fe-poor and Fe-bearing K-dioctahedral micas provided a generalized set of FTIR identification criteria that include the band positions and profiles in the regions of Si–O bending, Si–O stretching, and OH-stretching vibrations. FTIR data allow unambiguous identification of illites, aluminoceladonites, and celadonites, as well as distinction between Fe-illites and illites proper, as well as between Al-glauconites and glauconites. Specifically, a sharp maximum from the AlOHMg stretching vibration at ~3600 cm−1, the presence of a MgOHMg stretching vibration at 3583–3585 cm−1, as well as characteristic band positions in the Si–O bending (435–439, 468–472 and 509–520 cm−1) and stretching regions (985–1012 and 1090–1112 cm−1) are clearly indicative of aluminoceladonite. The distinction between Fe-illites and Al-glauconites, which have similar FTIR features, requires data on cation composition and unit-cell parameters.

Magnetic Properties and Structural Transformation in Copper-304 Stainless Steel Multilayer Materials

1995 ◽  
Vol 382 ◽  
Author(s):  
K. Parvin ◽  
S.P. Weathersby ◽  
T.W. Barbee ◽  
T.P. Weihs ◽  
M.A. Wall
Keyword(s):  
Stainless Steel ◽  
Magnetic Moment ◽  
Magnetic Moments ◽  
High Volume ◽  
304 Stainless Steel ◽  
X Ray Diffraction ◽  
Multilayer Foils ◽  
Large Period ◽  
Fcc Phase ◽  
Bcc Phase

ABSTRACTMultilayer foils of Cu-304 stainless steel (304SS) with equal layer thicknesses in the range t=5.0-500 Å and total thicknesses 10-20 μm have been synthesized using magnetron sputtering at ambient substrate temperature. The x-ray diffraction data of as-deposited films show two structural regimes: small thickness (t=5-10 Å) which is characterized by epitaxial FCC growth of 304SS on copper, and large thickness (t=13.5-500 Å) which shows epitaxial FCC 304SS growth near the interface and BCC 304SS growth away from the interface. FCC structured films show very small magnetic moments at room temperature similar to bulk 304SS stable FCC phase. However, a strong magnetic moment is observed for thicker samples due to ferromagnetic metastable 304SS BCC phase. Two opposing transformations occur in the 304 layers as the samples are heated. The first transformation is from the metastable BCC 304SS to the stable FCC phase. This transformation produces a strong drop in magnetic moment and is clearly visible in the large period multilayers which contain high volume fractions of BCC 304SS. The second transformation is from the original FCC phase to a new stable BCC phase in the 304SS near the copper-304SS interfaces.The transformation is produced by diffusion of nickel from the 304SS into the surroundingcopper and the chemical destabilization of the FCC phase which starts near 400 ºC.This transformation produces a sharp increase in magnetic moment. The magnetic signal drops to zero near 675 ºC which is the Curie temperature of ferromagnetic BCC Fe.75 Cr25..

Die Schwingungsfeinstruktur der Elektronenspektren des 13C- und 18O-markierten trans-Dioxotetracyanoosmats (VI),[OsO2(CN)4]2 -

1988 ◽  
Vol 43 (3) ◽  
pp. 239-247 ◽  
Author(s):  
C. Sartori ◽  
W. Preetz
Keyword(s):  
Ground State ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Isotopic Shifts ◽  
Charge Transfer Transitions ◽  
Stretching Vibration ◽  
Stretching Vibrations ◽  
The One ◽  
Franck Condon ◽  
Electronic Ground

The electronic absorption spectrum of the solid tetramethyl-ammonium salt of [OsO2(CN)4]2 - is measured at 10 K. The five distinct band systems exhibit vibrational progressions in the range 660-750 cm - 1, corresponding to the Os = O stretching vibrations sometimes coupled with ν(OsC). From this vibrational fine structure the electronic origin is deduced and verified by characteristic isotopic shifts by 18O and 13C. The two bands at lowest energy are assigned to the d-d-transitions 1A1g [b22g] → 3Eg [b12g e1g] (620 - 460 nm) and 1A1g [b22g] → 1Eg [b12g e1g] (490 - 400 nm). The 3Eg state is split by spin-orbit coupling into 5 components, from the one at lowest energy a luminescence emission (830 - 670 nm) takes place with a progression of 860 cm-1, corresponding to the symmetric Os = O stretching vibration in the electronic ground state. The more intense bands are assigned to charge transfer transitions from oxo π-orbitals into unoccupied niveaus of Os (VI): 1A1g [e4u] → 3A2u [e3u e1g] (390 - 340); → 1A1u [e3u e1g] (340 - 290) and → 1Eu [e3u b11g (290 - 230 nm). The singlet-triplet distances are 3200-3600 cm - 1. From a Franck-Condon analysis an excited state elongation of 10-13 pm for the osmyl groups is calculated.

scholarly journals The Spin Periods of Magnetic Cataclysmic Variables

2004 ◽  
Vol 190 ◽  
pp. 216-229 ◽  
Author(s):  
A. J. Norton ◽  
R. V. Somerscales ◽  
G. A. Wynn
Keyword(s):  
Orbital Period ◽  
Magnetic Moment ◽  
White Dwarf ◽  
Magnetic Moments ◽  
Cataclysmic Variables ◽  
Intermediate Polars ◽  
Magnetic Cataclysmic Variables ◽  
Remarkable Agreement

AbstractWe have used a model of magnetic accretion to investigate the rotational equilibria of magnetic cataclysmic variables (MCVs). This has enabled us to derive a set of equilibrium spin periods as a function of orbital period and magnetic moment which we use to estimate the magnetic moments of all known intermediate polars. We further show how these equilibrium spin periods relate to the polar synchronisation condition and use these results to calculate the theoretical histogram describing the distribution of magnetic CVs as a function of Pspin/Porb. We demonstrate that this is in remarkable agreement with the observed distribution assuming that the number of systems as a function of white dwarf magnetic moment is distributed according to .

Copper complexes of polyfunctional phthalazines. Mononuclear and polynuclear derivatives

1982 ◽  
Vol 60 (20) ◽  
pp. 2583-2593 ◽  
Author(s):  
Dorothy V. Bautista ◽  
John C. Dewan ◽  
Laurence K. Thompson
Keyword(s):  
Copper Complexes ◽  
Magnetic Moments ◽  
Magnetic Data ◽  
Binuclear Complexes ◽  
Tetradentate Ligands ◽  
Binuclear Structure ◽  
Neutral Ligands ◽  
Hydroxide Bridge ◽  
Anionic Groups ◽  
Protonated Complexes

Mononuclear, binuclear, and trinuclear copper(II) complexes of the tetradentate ligands 1,4-di(2′-pyridyl) aminophthalazine (PAP) and 1,4-di(4′-methyl-2′-pyridyl) aminophthalazine (PAP4Me) and binuclear complexes of the tetradentate ligand 1,4-di(6′-methyl-2′-pyridyl) aminophthalazine (PAP6Me) are reported. In a series of binuclear carboxylate derivatives carboxylate bridges exist between copper centres in all cases and in some cases oxygen bridges (hydroxide or methoxide) are indicated. In all other polynuclear derivatives hydroxide bridges are anticipated on the basis of analytical, spectral, and magnetic data. The ligands exist as anionic groups in some binuclear carboxylate derivatives while in the other polynuclear systems neutral ligands are found. In reactions in aqueous solution protonated mononuclear derivatives are obtained for both PAP and PAP4Me in cases where solutions of the metal salts are inherently acidic, followed by polynuclear, neutral ligand complexes which form when the pH increases. Mononuclear protonated complexes are not obtained with PAP6Me, where steric factors may prevent the formation of such derivatives. Low magnetic moments (1.1–1.5 BM) are observed for most hydroxy bridged complexes while even lower values ( < 0.70 BM ) are observed for two binuclear complexes of PAP6Me, indicating the possibility of strong antiferromagnetic exchange between metal centres. A preliminary X-ray investigation of the complex [Cu2(PAP4Me)(OH)(NO3)2(H2O)2]NO3 indicates a triple bridged binuclear structure including a bidentate nitrate bridge and a hydroxide bridge with an oxygen bridge angle of 115.2°.

ENHANCEMENT OF Fe MAGNETIC MOMENTS IN FERROMAGNETIC Fe16B2, Fe16C2, AND Fe16N2

1993 ◽  
Vol 07 (01n03) ◽  
pp. 729-732 ◽  
Author(s):  
B.I. MIN
Keyword(s):  
Magnetic Moment ◽  
Density Functional ◽  
Local Density ◽  
Magnetic Moments ◽  
Local Environment ◽  
Electronic Structure Calculations ◽  
Orbital Contribution ◽  
Large Enhancement ◽  
Band Method ◽  
Structure Calculations

In order to investigate electronic and magnetic properties of Fe16X2 (X=B, C, N) ferromagnet, we have performed electronic structure calculations employing the total energy self-consistent local density functional linearized muffin tin orbital (LMTO) band method. Large enhancement of the magnetic moment is observed in FeII and FeIII, which are located farther from X than FeI. This suggests that the local environment plays a very important role in determining Fe magnetic moments in these compounds. Orbital contribution to the magnetic moment in Fe atoms of Fe16N2 is minor, totalof ~0.6 μB in the unit cell. We have obtained the average magnetic moments per Fe atom, 2.30, 2.40, and 2.50 μB, in Fe16B2, Fe16C2, and Fe16N2, respectively.

Vibrational band intensities in substituted anilines

1957 ◽  
Vol 243 (1233) ◽  
pp. 143-153 ◽  
Keyword(s):  
Linear Relation ◽  
Vibrational Band ◽  
Vibration Band ◽  
Substituted Anilines ◽  
Absorption Bands ◽  
Bond Stretching ◽  
Infra Red ◽  
Analogous Data ◽  
Stretching Vibration ◽  
Stretching Vibrations

The infra-red absorption bands associated with the stretching vibrations of the NH 2 group in a series of meta - and para -substituted anilines have been examined. The effect of the sub­stituet groups upon the frequencies and intensities of the bands has been correlated with their Hammett σ factors. The widths of the bands have also been found to depend upon the position and nature of substituent. The linear relation between log (intensity) and σ suggested previously on the basis of other data has been found to hold in this case too. Measurements in several solvents have been compared, and surprising variations of band intensity have been found. Analogous data have been obtained for the N—H bond stretching vibration band in substituted N -methyl anilines. The effect of ortho substituents has also been examined in a few cases.

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