Preparations, Magnetic Susceptibility and Structural Studies of Trinuclear Copper(II) Compounds of 4,4,9,9-Tetramethyl-5,8-diazadodecane-2,11-diol

1988 ◽  
Vol 41 (10) ◽  
pp. 1545 ◽  
Author(s):  
NF Curtis ◽  
GJ Gainsford ◽  
KR Morgan
Keyword(s):  
Magnetic Susceptibility ◽  
Magnetic Moments ◽  
Spin Coupling ◽  
Structural Studies ◽  
Magnetic Susceptibilities ◽  
X Ray ◽  
Square Planar ◽  
Coupling Parameters ◽  
Temperature Ranges ◽  
Oxygen Atoms

Reduction of 4,4,9,9-tetramethyl-5,8-diazadodecane-2,11-dione yields the meso and racemo isomers of 4,4,9,9-tetramethyl-5,8-diazadodecane- 2,11-diol which form trinuclear compounds [Cu3( amat )2](ClO4)2 with all ligand alcohol groups deprotonated . The structure of the compound of the racemo amino alcohol has been determined by X-ray diffractometry [space group, P21/c, a 1594.5(4), b 1786.0(5), c 1419.1(4) pm, β 104.84(2)°, R 0.040, Rw 0.049 for 3466 reflections]. The cation has three copper(II) ions close to colinear (Cu-Cu 294 pm, Cu-Cu-Cu 177°), with the terminal copper(II) ions coordinated by the two nitrogen and two oxygen atoms of the tetradentate diamine-diolato ligand, and the central copper(II) ion by the oxygen atoms of the two ligands . All copper(II) ions have coordination environments intermediate between square planar and tetrahedral, the distortion from square planar being greater for the central ion [angle between planes O2Cu,CuO2 is 45°, compared with 16° between the planes N2Cu,CuO2 of the terminal copper(II) ions]. The magnetic susceptibilities of the compounds, measured over the temperature ranges 96-269 and 99-360 K for the racemo and meso isomers, respectively, are similar. Calculated effective magnetic moments/copper atom range from 1.07 μB at 99 K to 1.28 μB at 360 K. The susceptibility values were fitted to the expression for three spin-coupled copper(II) ions, with resultant spin coupling parameters, J, between adjacent atoms of -212 cm-1 ( meso-amat )and -230 cm-1 (racemo-amat ).

scholarly journals X-ray photoelectron spectra of iron-sulphur proteins

1975 ◽  
Vol 149 (2) ◽  
pp. 471-474 ◽  
Author(s):  
P T Andrews ◽  
C E Johnson ◽  
B Wallbank ◽  
R Cammack ◽  
D O Hall ◽  
...  
Keyword(s):  
Magnetic Susceptibility ◽  
Magnetic State ◽  
High Potential ◽  
Spin Coupling ◽  
Photoelectron Spectra ◽  
Clostridium Pasteurianum ◽  
Active Centre ◽  
Core Polarization ◽  
X Ray ◽  
Polarization Splitting

The X-ray photoelectron spectra of the 2p, 3s and 3p levels of iron in oxidized Clostridium pasteurianum ferredoxin indicate that the eight iron atoms in the molecule are indistinguishable. Their magnetic state is indicated both by core polarization splitting of the 3s electrons, and by ‘shake-up’ satellites on the 2p lines. Similar satellites are observed in the 2p lines of reduced Chromatium high-potential iron-sulphur proteins and oxidized spinach ferredoxin, indicating that there too the iron atoms are magnetic. The low observed magnetic susceptibility of these proteins is therefore due to spin-coupling between the iron atoms in the active centre.

scholarly journals Синтез, структура и магнитные свойства многослойных наногетероструктур Fe|MgO|Cr|MgO|Fe

2021 ◽  
Vol 63 (9) ◽  
pp. 1306
Author(s):  
Е.М. Якунина ◽  
Е.А. Кравцов ◽  
Yu.N. Khaydukov ◽  
Н.О. Антропов ◽  
В.В. Проглядо
Keyword(s):  
Magnetic Properties ◽  
High Resolution ◽  
Exchange Interaction ◽  
Magnetic Moments ◽  
Ferromagnetic Material ◽  
Structural Studies ◽  
X Ray ◽  
Structural And Magnetic Properties ◽  
Metal Layers

Layered nanoheterostructures Fe | MgO | Cr | MgO | Fe is an artificial ferromagnetic material in which the exchange interaction of the magnetic moments of Fe layers through intermediate dielectric and metal layers can lead to magnetic configurations that are not realized in the well-studied Fe | MgO | Fe and Fe | Cr | Fe. In this work, we investigated the correlations of the structural and magnetic properties of layered nanoheterostructures Fe (10 nm) | MgO (1.5 nm) | Cr (t nm) | MgO (1.5 nm) | Fe (7 nm) (thickness t = 0.9 and 1.8 nm). Structural studies performed using X-ray diffractometry and high-resolution reflectometry confirmed the formation of a textured structure and revealed its well-defined layered character with sharp interlayer boundaries.

Zur Struktur des Enols von Benzoylaceton / On the Structure of the Enol of Benzoylacetone

1979 ◽  
Vol 34 (11) ◽  
pp. 1606-1611 ◽  
Author(s):  
W. Winter ◽  
K.-P. Zeller ◽  
S. Berger
Keyword(s):  
Structural Model ◽  
Chemical Shifts ◽  
Ring System ◽  
Coupling Constants ◽  
Spin Coupling ◽  
X Ray ◽  
Wide Range ◽  
Spin Coupling Constants ◽  
C Nmr ◽  
Oxygen Atoms

Abstract A low temperature X-ray study of the enol of benzoylacetone indicates fixed positions of the C and O atoms within the enolic ring system and an extensive bond delocalisation over these atoms. The distribution of electron density between the two oxygen atoms shows that the enolic hydrogen is spread over a wide range. This is in accordance with a structural model proposed by de la Vega, whereupon the C and O atoms are kept fixed in their average positions during a tunneling process of the hydrogen between the two oxygen atoms. With this conception, the chemical shifts in the 17O and 13C NMR spectra, the 13C13C spin coupling constants and the temperature independance of these values can be explained.

MAGNETIC AND STRUCTURAL PROPERTIES OF SOME ABa2Cu3O7−δ SUPERCONDUCTORS

1987 ◽  
Vol 01 (03n04) ◽  
pp. 989-992 ◽  
Author(s):  
M.T. Causa ◽  
S.M. Dutrús ◽  
C. Fainstein ◽  
G. Nieva ◽  
H.R. Salva ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Electrical Resistivity ◽  
Magnetic Susceptibility ◽  
Specific Heat ◽  
Powder Diffraction ◽  
Magnetic Moments ◽  
Superconducting Properties ◽  
X Ray ◽  
Structural Modifications

We report here normal and superconducting properties of ABa 2 Cu 3 O 7−δ (with A=Y, Gd, Dy, and Er) and of Fe doped YBa2Cu3O7−δ . Results from X-ray powder diffraction, electrical resistivity, magnetic susceptibility, ESR, and specific heat measurements are presented, leading to a characterization of the magnetic properties of these materials. The effect of structural modifications of the lattice on the superconducting properties and the relative insensitivity of Tc to the presence of magnetic moments is discussed.

Magnetic properties and structure of some copper(II) complexes of pyridine and quinoline N-oxides

1967 ◽  
Vol 20 (11) ◽  
pp. 2403 ◽  
Author(s):  
SJ Gruber ◽  
CM Harris ◽  
E Kokot ◽  
SL Lenzer ◽  
TN Lockyer ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
Magnetic Moments ◽  
Paramagnetic Complex ◽  
Water Molecules ◽  
Acetate Monohydrate ◽  
Binuclear Copper ◽  
Kcal Mole ◽  
Ferromagnetic Interaction ◽  
Magnetic Susceptibilities

The magnetism of various copper(II) complexes of pyridine and quinoline N-oxides1 has been further investigated. The compounds Cu(C5H5NO)nX2 (where n = 4 or 6, X = ClO4; n = 2, X = Cl, Br, NCS; n = 1, X = Cl, Br, CH3COO) and Cu(C9H7NO)nX2 where n = 4, X = ClO4; n = 2, X = Cl, Br, NO3; n = 1, X = Cl, Br, CH3COO) have been studied. The variation of the magnetic susceptibilities of most of these compounds is reported over a temperature range. The variation of the magnetic susceptibility with temperature for the weakly paramagnetic complex Cu(C5H5NO)Cl2 is discussed in terms of the binuclear oxygen-bridged structure previously postulated.1 The compound exhibits anti-ferromagnetic interaction between pairs of copper(II) atoms with a singlet-triplet separation of 2.1 kcal/mole. The compounds Cu(C5H5NO)2Cl2, Cu(C5H5NO)Br2, and Cu(C9H7NO)X2 (X = Cl, Br) are more weakly paramagnetic due to a larger singlet-triplet separation. The compound Cu(C5H5NO)2Br2 possesses a higher paramagnetic susceptibility than those of the previous compounds, and its magnetic properties are consistent with a dimeric structure involving a singlet- triplet separation of 0.7 kcal/mole. The copper(II) acetate adducts, Cu(CH3COO)2,L (L = C5H5NO or C9H7NO), possess very similar magnetic properties to binuclear copper(II) acetate monohydrate and presumably possess a similar structure, with the N-oxides replacing the water molecules. These compounds exhibit singlet-triplet energies of c. 1 kcal/mole similar to values reported for a large number of copper(II) alkanoates. The compounds Cu(C5H5NO)2(NCS)2, Cu(C5H5NO)4(ClO4)2, Cu(C5H5NO)6- (ClO4)2, Cu(C9H7NO)2X2 (X = Cl, Br, NO3), all obey the Curie-Weiss law and possess mean magnetic moments of 1.89, 1.80, 1.93, 1.88, 1.96, and 1.88 B.M. (corrected for θ values of -12, -7, -8, + -4, and -16�) respectively.

Some metal-ion complexes with ligands formed by reactions of amines with aliphatic carbonyl compounds. X. Compounds of some tridentate ligands formed by reaction of copper(II) 2-Aminoethanol and 3-Aminopropan-1-ol complexes with 4-Amino-(and 4-Hydroxy)-4-methylpentan-2-one

1980 ◽  
Vol 33 (8) ◽  
pp. 1695 ◽  
Author(s):  
KR Morgan ◽  
NF Curtis
Keyword(s):  
Magnetic Susceptibility ◽  
Carbonyl Compounds ◽  
Metal Ion ◽  
Spin Coupling ◽  
Tridentate Ligands ◽  
Metal Ion Complexes ◽  
Magnetic Susceptibilities ◽  
Condensation Products ◽  
Antiferromagnetic Spin

Compounds of copper(II) perchlorate with 2-aminoethanol (etol) and 3- aminopropan-1-ol (prol) react with 4-amino-4-methylpropan-2-one (amp), and with 4-hydroxy-4-methylpropan-2-one (hmp), to form compounds of stoichiometry [Cu(L)] ClO4, where (L) is a tridentate amine imine olato ligand from amp, or a hydroxy imine olato ligand from hmp. The etol condensation products have 'normal' magnetic susceptibilities, while the prol condensation products show antiferromagnetic spin-coupling. The prol/amp product is diamagnetic at 300 K (-J > 700 cm-1) and the prol/hmp product has a J of -186 cm-1, based on magnetic susceptibility measurements over 100-300 K. Preparations of some related nitrate, thiocyanate and tetrachlorozincate compounds are reported. Possible structures for the compounds are discussed.

Ternary indides RE3T2In4 (RE=Dy–Tm; T=Pd, Ir)

2018 ◽  
Vol 73 (11) ◽  
pp. 765-772 ◽  
Author(s):  
Sebastian Stein ◽  
Lukas Heletta ◽  
Rainer Pöttgen
Keyword(s):  
Magnetic Susceptibility ◽  
Rare Earth ◽  
Transition Metal ◽  
Magnetic Moments ◽  
Hexagonal Structure ◽  
Temperature Dependent ◽  
X Ray ◽  
Wyckoff Position ◽  
Different Types ◽  
High Temperature Reactions

AbstractThe ternary rare earth transition metal-indides RE3T2In4 (RE=Dy–Tm; T=Pd, Ir) were obtained from high-temperature reactions in sealed niobium ampoules. These indides adopt a hexagonal structure of the Lu3Co1.87In4 type (space group P6̅), a ternary ordered superstructure of the aristotype Fe2P. The structures of three different compounds were refined from single-crystal X-ray diffractometer data: a=768.20(6), c=381.97(3) pm, 1441 F2 values, 24 parameters, wR2=0.0338 (Ho3Pd1.90In4); a=774.98(3), c=378.51(2) pm, 577 F2 values, 23 parameters, wR2=0.0742 (Ho3Ir1.69In4.31) and a=780.3(1), c=369.4(1) pm, 573 F2 values, 22 parameters, wR2=0.0403 (Tm3Ir1.51In4.49). Refinements of the occupancies revealed homogeneity ranges in case of the iridium-based crystals resulting from Ir/In mixing. The refined composition of the palladium compound was Ho3Pd1.90In4 resulting from defects on the Wyckoff position 1d, which was already reported for the prototype Lu3Co1.87In4. The geometrical motifs of the RE3T2In4 structures are three different types of tricapped trigonal prisms around the transition metal and indium atoms which are condensed via common edges and triangular faces. Temperature dependent magnetic susceptibility measurements of Dy3Ir2In4 and Tm3Ir2In4 showed Curie-Weiss behavior and the experimental magnetic moments of 10.59(2) μB (Dy3Ir2In4) and 7.40(2) μB (Tm3Ir2In4) confirming stable trivalent RE3+ states. Dy3Ir2In4 and Tm3Ir2In4 order antiferromagnetically with Néel temperatures of TN=13.6(5) and 5.4(5) K, respectively.

Magnetism, electronic spectra, and structure of transition metal alkoxides. II. The preparation and magnetism of iron(III) alkoxides

1966 ◽  
Vol 19 (3) ◽  
pp. 363 ◽  
Author(s):  
RW Adams ◽  
RL Martin ◽  
G Winter
Keyword(s):  
Room Temperature ◽  
Benzene Solution ◽  
Magnetic Moments ◽  
Exchange Interactions ◽  
Metal Alkoxides ◽  
Antiferromagnetic Exchange ◽  
Crystal Data ◽  
Magnetic Susceptibilities ◽  
X Ray ◽  
The Core

The iron(III) alkoxides, Fe(OMe)3, Fe(OEt)3, and Fe(Obun)a have been prepared by a procedure alternative to those previously described in the literature. The trimeric nature of the three compounds in benzene is confirmed by cryoscopy, and preliminary X-ray single crystal data for the ethoxide are consistent with trimeric entities in the solid. The temperature variation of the magnetic susceptibilities for the three compounds follows the Curie-Weiss law between 90 and 300�K but with large values of θ=- 200�K. The unusually low magnetic moments vary markedly with temperature, and at room temperature remain depressed in benzene solution at peer μeff 4.4 B.M. This anomalous behaviour is ascribed to the presence of weak antiferromagnetic exchange interactions within the cluster of iron atoms which forms the core of the trimeric species Fe3(0R)9. The compounds are sensitive both to hydrolysis and to heating. Hydrolysis decreases and pyrolysis increases the magnetic susceptibility. This provides a convenient method for following the progress of both types of reaction.

Magnetic Susceptibility and Structure of Some Transition Metal (II) Complexes with 1,2,4-Triazole

1977 ◽  
Vol 32 (7) ◽  
pp. 783-784 ◽  
Author(s):  
D. W. Engelfriet ◽  
J. G. Haasnoot ◽  
W. L. Groeneveld
Keyword(s):  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
Transition Metal ◽  
Metal Ions ◽  
Single Crystal ◽  
Two Dimensional ◽  
Single Crystal Diffraction ◽  
Magnetic Susceptibilities ◽  
X Ray

Abstract The magnetic susceptibilities of some transition metal (II) complexes with 1,2,4-triazole (trz) have been measured in the range 2-300 K. Ni (trz)2 (NO3)2 (H2O) 8/3, Ni (trz)2 SO4 (H2O)5 and α-Ni (trz)2 (NCS)2 are found to be linear antiferromagnetic trimers. For β- Ni (trz)2 (NCS)2 and similar compounds with Mn (II), Fe (II), Co (II) and Cu(II), totally different magnetic properties were observed, suggesting the presence of two-dimensional networks of metal ions bridged by 1,2,4-triazole molecules. For Co (trz) 2 (NCS) 2 this was confirmed by X-ray single crystal diffraction.

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