Magnetic studies of Hexakis(antipyrene)manganese(II) perchlorate

1977 ◽  
Vol 30 (7) ◽  
pp. 1461 ◽  
Author(s):  
DJ Mackey
Keyword(s):  
Magnetic Anisotropy ◽  
Zero Field ◽  
Zero Field Splitting ◽  
Magnetic Studies ◽  
Zero Field Splitting Parameter ◽  
Diamagnetic Contribution ◽  
Splitting Parameter ◽  
Magnesium Complexes ◽  
Host Lattices ◽  
Spherical Crystals

The magnetic anisotropy of Mn(antipyrene)6(ClO4)2 below 20 K indicates that the zero-field splitting parameter (D) is about three times greater than obtained from e.p.r. measurements of manganese doped into a series of isomorphous host lattices. Shape anisotropy effects are significant unless spherical crystals are used. The interpretation of the magnetic anisotropy above 20 K is complicated by the large diamagnetic contribution from the ligands and it is suggested that there are significant differences in the orientation of the ligand molecules in the isomorphous manganese and magnesium complexes.

Modulation of the coordination environment: a convenient approach to tailor magnetic anisotropy in seven coordinate Co(ii) complexes

2016 ◽  
Vol 52 (4) ◽  
pp. 753-756 ◽  
Author(s):  
Mamon Dey ◽  
Snigdha Dutta ◽  
Bipul Sarma ◽  
Ramesh Ch. Deka ◽  
Nayanmoni Gogoi
Keyword(s):  
Magnetic Anisotropy ◽  
Zero Field ◽  
Zero Field Splitting ◽  
Field Splitting ◽  
Coordination Environment ◽  
Zero Field Splitting Parameter ◽  
Convenient Approach ◽  
Splitting Parameter ◽  
Remarkable Deviation

Subtle modulation of the coordination environment in seven coordinate Co(ii) complexes leads to a remarkable deviation in the axial zero field splitting parameter (D) in a predictable fashion.

Correlating magnetic anisotropy with the subtle coordination geometry variation of a series of cobalt(ii)-sulfonamide complexes

2019 ◽  
Vol 48 (41) ◽  
pp. 15419-15426 ◽  
Author(s):  
Tao Wu ◽  
Yuan-Qi Zhai ◽  
Yi-Fei Deng ◽  
Wei-Peng Chen ◽  
Tao Zhang ◽  
...  
Keyword(s):  
Magnetic Anisotropy ◽  
Zero Field ◽  
Coordination Geometry ◽  
Zero Field Splitting ◽  
Tetrahedral Geometry ◽  
Coordination Environment ◽  
Zero Field Splitting Parameter ◽  
Mononuclear Cobalt ◽  
Splitting Parameter ◽  
The Ideal

The distortion degree from the ideal tetrahedral geometry has been correlated with the zero-field splitting parameter in a series of mononuclear cobalt(ii)-sulfonamide complexes with a CoN4 coordination environment.

scholarly journals Redetermination of Zero-Field Splitting in [Co(qu)2Br2] and [Ni(PPh3)2Cl2] Complexes

2016 ◽  
Vol 15 (2) ◽  
pp. 200-211 ◽  
Author(s):  
Dominik Lomjanský ◽  
Filip Varga ◽  
Cyril Rajnák ◽  
Ján Moncoľ ◽  
Roman Boča ◽  
...  
Keyword(s):  
Magnetic Anisotropy ◽  
Ab Initio ◽  
Molecular Structures ◽  
Zero Field ◽  
Squid Magnetometry ◽  
Zero Field Splitting ◽  
Field Splitting ◽  
Crystal And Molecular Structures ◽  
Zero Field Splitting Parameter ◽  
Splitting Parameter

AbstractA mononuclear CoII complex, [Co(qu)2Br2], and NiII complex, [Ni(PPh3)2Cl2], (qu = quinoline, PPh3 = triphenylphosphine) have been reinvestigated. Their crystal and molecular structures are reported along with IR and UV-Vis spectra. Magnetism of both complexes has been studied by using the DC SQUID magnetometry. These complexes exhibit a moderate magnetic anisotropy expressed by zero-field splitting parameter D. The D-value is positive for both complexes with D/hc = +5.94 cm−1 and D/hc = +12.76 cm−1, that is also confirmed by ab initio calculations.

Probing the influence of molecular symmetry on the magnetic anisotropy of octahedral cobalt(ii) complexes

2017 ◽  
Vol 4 (11) ◽  
pp. 1909-1916 ◽  
Author(s):  
Zhong-Yu Ding ◽  
Yin-Shan Meng ◽  
Yi Xiao ◽  
Yi-Quan Zhang ◽  
Yuan-Yuan Zhu ◽  
...  
Keyword(s):  
Magnetic Anisotropy ◽  
Octahedral Geometry ◽  
Zero Field ◽  
Molecular Symmetry ◽  
Zero Field Splitting ◽  
Field Splitting ◽  
Zero Field Splitting Parameter ◽  
Splitting Parameter

A series of field-induced cobalt(ii) SIMs exhibit varying axial zero-field splitting parameter D values from positive to negative with the increased distortion of the octahedral geometry.

Correlation of Zero Field Splittings and Site Distortions V. Mn2+ in Cs2Zn3S4

1983 ◽  
Vol 38 (2) ◽  
pp. 149-153 ◽  
Author(s):  
M. Heming ◽  
G. Lehmann
Keyword(s):  
Fine Structure ◽  
Hyperfine Splitting ◽  
Site Symmetry ◽  
Zero Field ◽  
Structure Parameters ◽  
Zero Field Splitting ◽  
Zero Field Splitting Parameter ◽  
Free Ion ◽  
Splitting Parameter ◽  
Epr Signal

Abstract In platelets of Cs2Zn3S4 with about 4% of the Zn substituted by Mn two nonequivalent centers of isolated Mn2+ were observed in addition to a broad EPR signal near g = 2 which is assigned to clusters of interconnected MnS4 units. The fine structure and hyperfine structure parameters for the single-ion centers (all in units of 1CT 4 cm -1) areb02 = -318.3 ± 3; b22 = -210.3 ± 2; Ay = -62.7; Az = -63.6 ± 0.8;b02 = -890 ± 18; b22 = -743 ± 36; Ay = -60.6; Az = - 61.4 ± 0.8;for centers I and II, resp. Center II arises from Zn sites of C 2 site symmetry while for center I assignment to either one of two sites with D2 site symmetry is possible. The larger hyperfine splitting constants as well as the superposition analysis favor the larger sites which are not occupied by Zn, but are partly occupied in the analogous Mn (and Co) compounds. Superposition analysis yields the same value of + 0.12 ± 0.02 cm-1 for the intrinsic zero field splitting parameter b̄2 of the bridging MnS4 units in both sites. gz is significantly higher than the free ion value indicating a higher degree of covalency than in Cds and CdGa2S4.

scholarly journals Abnormal Magnetic Moment and Zero Field Splitting of Some Nickel (II) Complexes

2017 ◽  
Vol 7 (1) ◽  
pp. 34
Author(s):  
Rajeev Ranjan ◽  
Navneet Sinha ◽  
Sahdeo Kumar ◽  
Chandra Mauleshwar Chandra ◽  
Shivadhar Sharma
Keyword(s):  
Magnetic Moment ◽  
Metal Ion ◽  
Free Ligand ◽  
Tetragonal Distortion ◽  
Zero Field ◽  
Zero Field Splitting ◽  
Absorption Bands ◽  
Field Splitting ◽  
Zero Field Splitting Parameter ◽  
Splitting Parameter

<em>Some complexes of Ni(II) have been prepared with 2-thio-3-acetyl hydantoin (TAHN) and 2-formyl pyridine thiosemicarbazone (FPTS). On the basis of elemental analysis and molar conductivity, the complexes have been formulated as NiL<sub>2</sub>X<sub>2</sub>, where L = TAHN or FPTS and X = Cl<sup>–</sup>, Br<sup>–</sup>, NCS<sup>–</sup>, ClO<sub>4</sub><sup>–</sup>. The infrared spectra of complexes and free ligand reveal that the ligand TAHN is co-ordinated through sulphur and acetyl oxygen, while FPTS ligand co-ordinates through heterocyclic nitrogen and sulphur to Ni(II) metal ion. The magnetic moment of these complexes are found to be 3.20-3.25 B.M. The values are greater than value (2.828 B.M) corresponding to two unpaired electrons of a d<sup>8</sup>-system. The appearance of four absorption bands in their electronic spectra reveal, the tetragonal distortion in the octahedral symmetry of complexes. The zero field splitting parameter(D) and the other crystal field parameters like Dq<sub>(xy)</sub>, Dq<sub>(z)</sub>, Dt have been calculated. The results show that, the tetragonal distortion parameter (Dt) increases in the order of NCS<sup>– </sup>&lt; Cl<sup>–</sup> &lt; Br<sup>–</sup> while the zero field splitting parameter (D) also increases in the same order for both the planer ligands.</em>

Electron Spin Resonance of Cr3+ in K1–xTlxAl(SO4)2 · 12 H2O

2003 ◽  
Vol 58 (5-6) ◽  
pp. 303-305 ◽  
Author(s):  
V. K. Jain
Keyword(s):  
Electron Spin Resonance ◽  
Electron Spin ◽  
Metal Ion ◽  
Zero Field ◽  
Zero Field Splitting ◽  
Trivalent Metal ◽  
Zero Field Splitting Parameter ◽  
Monovalent Ions ◽  
Spin Resonance ◽  
Splitting Parameter

The electron spin resonance (ESR) of Cr3+ in K1−xTlxAl(SO4)2·12H2O has been studied at 300 K and 9.45 GHz. The ESR spectrum for x between 30 and 90% shows several chromium complexes. The variation of the zero-field splitting parameter D suggests that monovalent ions play an important role in the trigonal distortion of the water octahedron around the trivalent metal ion in alums. - PASC: 76.30 F.

Mixed valency in polynuclear Mn II /Mn III , Mn III /Mn IV and Mn II /Mn III /Mn IV clusters: a foundation for high-spin molecules and single-molecule magnets

2007 ◽  
Vol 366 (1862) ◽  
pp. 113-125 ◽  
Author(s):  
Theocharis C Stamatatos ◽  
George Christou
Keyword(s):  
Single Molecule ◽  
Exchange Interactions ◽  
Zero Field ◽  
Zero Field Splitting ◽  
Single Molecule Magnets ◽  
Zero Field Splitting Parameter ◽  
Jahn Teller ◽  
Splitting Parameter ◽  
Molecular Spin ◽  
Molecular Compounds

Mixed-valent Mn/O dinuclear and polynuclear molecular compounds containing Mn III are almost without exception trapped valence. Large differences between the strengths of the exchange interactions within Mn II Mn III , Mn III Mn III and Mn III Mn IV pairs lead to situations where Mn III Mn IV interactions, the strongest of the three mentioned and antiferromagnetic in nature, dominate the intramolecular spin alignments in trinuclear and higher nuclearity mixed-valent complexes and often result in molecules that have large, and sometimes abnormally large, values of molecular spin ( S ). When coupled to a large molecular magnetoanisotropy of the easy-axis-type (negative zero-field splitting parameter, D ), also primarily resulting from individual Jahn–Teller distorted Mn III centres, such molecules will function as single-molecule magnets (molecular nanomagnets). Dissection of the structures and exchange interactions within a variety of mixed-valent Mn x cluster molecules with metal nuclearities of Mn 4 , Mn 12 and Mn 25 allows a ready rationalization of the observed S , D and overall magnetic properties in terms of competing antiferromagnetic exchange interactions within triangular subunits, resulting spin alignments and relative orientation of Mn III JT axes. Such an understanding has provided a stepping stone to the identification of a ‘magnetically soft’ Mn 25 cluster whose groundstate spin S value can be significantly altered by relatively minor structural perturbations. Such ‘spin tweaking’ has allowed this cluster to be obtained in three different forms with three different groundstate S values.

SUPERPOSITION MODEL ANALYSIS FOR THE ZERO-FIELD SPLITTING OFMn2+IN SOME CRYSTALS

2006 ◽  
Vol 20 (30) ◽  
pp. 1917-1922 ◽  
Author(s):  
VIMAL KUMAR JAIN
Keyword(s):  
Lattice Relaxation ◽  
Zero Field ◽  
Superposition Model ◽  
Zero Field Splitting ◽  
Intrinsic Parameter ◽  
Order Zero ◽  
Field Splitting ◽  
Zero Field Splitting Parameter ◽  
Local Lattice ◽  
Splitting Parameter

The Newman superposition model has been applied to second-order zero-field splitting parameter [Formula: see text] taken from the literature for Mn2+in Hg(ClO4)2· 6 H2O , M ″ SiF6·6 H2O (M ″= Fe, Co, Zn ) and M ″ NbOF5·6 H2O (M ″= Co, Zn ). In the calculations, the local lattice relaxation has been taken into account. It is shown that nearly the same value of intrinsic parameter b2=-0.057(8) cm-1is obtained.

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