The Ground State in Tris(acetylacetonato)ruthenium(III) from Low-Temperature Single-Crystal Magnetic Properties

1998 ◽  
Vol 51 (3) ◽  
pp. 229 ◽  
Author(s):  
Philip A. Reynolds ◽  
Brian N. Figgis ◽  
Boujemaa Moubaraki ◽  
Keith S. Murray
Keyword(s):  
Ground State ◽  
Field Model ◽  
Ligand Field ◽  
Spin Orbit Coupling ◽  
Coupling Constant ◽  
Magnetic Exchange Interaction ◽  
Magnetic Exchange ◽  
Structural Details ◽  
Ligand Field Parameter ◽  
Good Agreement

The magnetic susceptibilities of tris(acetylacetonato)ruthenium(III) have been measured between 2·5 and 300 K along the a, b, c, and a* axis directions, together with the magnetizations along the same directions up to a magnetic field of 5 T. There is a small amount of magnetic exchange interaction apparent below 10 K, with Weiss constants up to –0·35 K and the magnetization is fitted with exchange integrals up to –0·38 K in magnitude. A pathway for magnetic exchange in terms of a pair of symmetry-related Ru(acac) rings lying parallel and close is obvious from the structure. The susceptibility results above 10 K have been interpreted in terms of a four-parameter ligand field model (CF1) operating on the ground 2T2g term of the d5 configuration. The t2g orbitals are found to be split by 475 cm-1 by a dominant trigonal symmetry component and then by –50 cm-1 by a subsidiary rhombic component. The single-electron spin-orbit coupling constant is 875 cm-1 and the orbital angular momentum reduction parameter is 0·7. The g-values deduced for the ground Kramers doublet are not in good agreement with those from e.s.r. experiments, but rather better agreement is found for closely allied ligand field parameter sets (CF2) which can fit the susceptibilities at particular temperatures but do not reproduce their temperature dependence well. Consideration of the variation of structural details with temperature indicate that, in fact, the CF2 sets may be more realistic.

Single-Crystal Magnetic Properties of [Co(NH3)5(OH2)] [Cr(CN)6] Between 2 and 300 K

1992 ◽  
Vol 45 (11) ◽  
pp. 1899 ◽  
Author(s):  
PA Reynolds ◽  
CD Delfs ◽  
BN Figgis ◽  
B Moubaraki ◽  
KS Murray
Keyword(s):  
Ising Model ◽  
Field Model ◽  
Mean Field ◽  
Zero Field ◽  
Spin Orbit Coupling ◽  
Zero Field Splitting ◽  
Magnetic Exchange Interaction ◽  
Mean Field Model ◽  
Magnetic Exchange ◽  
The Mean

The magnetic susceptibilities along and perpendicular to the c axis (hexagonal setting) between 2.0 and 300 K at a magnetic field of 1.00 T, and the magnetizations at field strengths up to 5.00 T, are presented for single crystals of [Co(NH3)5(OH2)] [Cr(CN)6]. The results are interpreted in terms of zero-field splitting (2D) of the ground 4A2g term by spin-orbit coupling and of magnetic exchange interaction between the chromium atoms. The magnetic exchange is modelled as one of Ising or mean-field in type. The exchange is found to be quite small: J = -0.18(6) cm-1 if the Ising model is employed, and -0.03(1) cm-1 for the mean-field model. The model adopted for the exchange has a strong influence on the value of the parameter D obtained. When the Ising model is used D is deduced to be -0.28(9) cm-l; when the mean-field model is used D is -0.14(4) cm-l. The g-values deduced are in agreement with those from e.s.r. measurements at higher temperatures and do not depend on the exchange model. In any case, D is found to be sufficiently large that it must be considered in a polarized neutron diffraction experiment on the compound.

Fluorosulfates of palladium

1977 ◽  
Vol 55 (13) ◽  
pp. 2473-2477 ◽  
Author(s):  
K. C. Lee ◽  
F. Aubke
Keyword(s):  
Ground State ◽  
Diffuse Reflectance ◽  
Magnetic Measurements ◽  
Structural Information ◽  
Tridentate Ligand ◽  
Ligand Field ◽  
Polymeric Structure ◽  
Octahedral Environment ◽  
Fluorosulfate Group ◽  
Ligand Field Parameter

The syntheses of Pd(SO3F)2 and Pd(SO3F)3 by the reactions of palladium with BrOSO2F and S2O6F2 are described. Structural information on both compounds is based on infrared, Raman, diffuse reflectance, and electronic mull spectra as well as magnetic measurements from ∼300 to ∼100 K. Palladium bisfluorosulfate is found to have a polymeric structure with the fluorosulfate group acting as a tridentate ligand. As a consequence, an octahedral environment is found for Pd2+ with a 3A2g ground state, a µeff298 value of 3.39 BM and the ligand field parameter Dq = 1177 cm−1 and B = 633 cm−1. Pd(SO3F)3 is best regarded as PdII[PdIV(SO3F)6].

Spin–orbit splitting in 2Δ states of diatomic molecules

1969 ◽  
Vol 47 (23) ◽  
pp. 2727-2730 ◽  
Author(s):  
H. Lefebvre-Brion ◽  
N. Bessis
Keyword(s):  
Diatomic Molecules ◽  
Orbit Interaction ◽  
Second Order ◽  
Orbit Coupling ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Coupling Constant ◽  
Orbit Splitting ◽  
Spin Orbit Splitting ◽  
Good Agreement

The origin of the splitting of the 2Δ states arising from the σπ2 configuration is studied. For light diatomic molecules, the splitting is shown to arise from the spin–other–orbit interaction which gives a small negative value for the spin–orbit coupling constant A. Non-empirical calculations of A for the 2Δ states of the CH, NH+, and NO molecules are in good agreement with experiment. In heavier molecules, the spin–other–orbit interaction becomes negligible and the second-order spin–orbit effect is dominant.

The magnetic behaviour of titanium and vanadium hexaurea salts at low temperatures

1980 ◽  
Vol 33 (11) ◽  
pp. 2377 ◽  
Author(s):  
J Baker ◽  
BN Figgis
Keyword(s):  
Low Temperatures ◽  
Magnetic Behaviour ◽  
Ligand Field ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Coupling Constant ◽  
Ambient Temperatures ◽  
Jahn Teller ◽  
Jahn Teller Effect ◽  
Ligand Field Parameters

The magnetic susceptibility and anisotropy of the iodide and perchlorate salts of the hexaureatitanium(III) and hexaureavanadium(III) ions have been measured between liquid helium and ambient temperatures. The analysis of the data in terms of a model involving the angular and radial parts of the ligand field parameters, B0/2, B0/4 and B3/4, the spin-orbit coupling constant, λ, and the orbital reduction parameter, k, yields values supporting earlier studies, but having greater reliability and in better agreement with the optical absorption spectra. It is suggested that the low values deduced for k and λ/λ0 may be due to the operation of a dynamic Jahn-Teller effect.

Magnetic exchange in 2,2'-bipyridyliron(III) chloride

1983 ◽  
Vol 36 (12) ◽  
pp. 2369 ◽  
Author(s):  
BN Figgis ◽  
ES Kucharski ◽  
PA Reynolds
Keyword(s):  
Field Model ◽  
Magnetic Order ◽  
Mean Field ◽  
Magnetic Behaviour ◽  
Integral Parameter ◽  
Mean Field Model ◽  
Magnetic Exchange ◽  
Structural Details ◽  
Exchange Network ◽  
Total Exchange

The magnetic susceptibility and anisotropy of cis-bis(2,2'-bipyridyl)dichloroiron(III) tetrachloroferrate(III), cis-[Fe(bpy)2Cl2]+ [FeCl4]-, have been measured between 1.8 and 300 K at magnetic fields up to 1 T. The magnetization on the cation and anion sites has been estimated by means of polarized neutron diffraction measurements at 1.5 and 4.6 T, and at temperatures from 2.1 to 41 K. These magnetic results may be fitted to a 'mean-field' model of magnetic exchange in which the total exchange integral parameter, ΣijJij, is c. -1.1 K. The magnetic results and structural details for the compound suggest that the strongest exchange pathway connects chains of alternating cations and anions. The inter-chain exchange is small. However, the substantial magnetic anisotropy and the much stronger decrease with temperature of the FeCl4- ion site moment, relative to that of the cation, both indicate a complex magnetic exchange network and consequent magnetic behaviour. No sign of magnetic order is observed to at least 2.9 K.

NOTIZEN: EPR- und ligandenfeld-spektroskopische Strukturuntersuchungen an Cu(II)-Verbindungen / Investigations with Respect to the Structure of Cu(II)-compounds by EPR and Ligand Field Spectroscopy

1975 ◽  
Vol 30 (11-12) ◽  
pp. 970-972 ◽  
Author(s):  
Claus Friebel
Keyword(s):  
Field Parameter ◽  
Ligand Field ◽  
Field Spectroscopy ◽  
Distorted Octahedral ◽  
Structural Details ◽  
Jahn Teller ◽  
Crystallographic Axes ◽  
Ligand Field Parameter

From EPR and ligand field parameter some significant structural details of Cu(II)-compounds can be determined to a notable accuracy: a) the symmetry (tetragonal or orhombic) of Jahn-Teller distorted octahedral Cu(II)-sites, and b) the ordering of Jahn-Teller coupled Cu(II)-polyhedra with respect to each other as well as to the crystallographic axes of the Cu(II)-compound under investigation.

Self-consistent fields without exchange for Pr3+ and Tm3+

1960 ◽  
Vol 56 (1) ◽  
pp. 41-54 ◽  
Author(s):  
E. Cicely Ridley
Keyword(s):  
Ground State ◽  
Orbit Coupling ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Coupling Constant ◽  
Self Consistent

ABSTRACTSelf-consistent fields without exchange have been calculated for the ground state of Pr3+ and Tm3+. The spin-orbit coupling constant ζ(4f) is found to have the values 785 and 2742 cm−1 in Pr3+ and Tm3+, respectively. The corresponding values of are 29·4 and 77·5 Å−3. Values of the Slater integrals F2(4f, 4f), F4(4f, 4f) and F6(4f, 4f) are also given for each structure.

Intra-molecular magnetic exchange interaction in the tripyridinium bis[tetrachloroferrate(iii)] chloride molecular magnet: a broken symmetry-DFT study

2015 ◽  
Vol 17 (29) ◽  
pp. 19119-19125 ◽  
Author(s):  
F. Baniasadi ◽  
M. M. Tehranchi ◽  
M. B. Fathi ◽  
N. Safari ◽  
V. Amani
Keyword(s):  
Magnetic Coupling ◽  
Dft Method ◽  
Broken Symmetry ◽  
Molecular Magnet ◽  
Coupling Constant ◽  
Magnetic Exchange Interaction ◽  
Magnetic Exchange ◽  
Electronic Spin ◽  
Density Maps ◽  
Magnetic Coupling Constant

A superexchange interaction path between Fe–Fe in (FeCl4)2(py·H)3Cl is illustrated making use of electronic spin density maps (ESDM) and the magnetic coupling constant is calculated using the BS-DFT method as JFe–Fe = 13.2062 kJ mol−1.

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