Metal pyrazolate polymers. Part 4. Synthesis, characterization, and magnetic properties of [Co(pz*)2]x complexes (where pz* = pyrazolate, 3-methylpyrazolate, and 4-substituted 3,5-dimethylpyrazolate)

1993 ◽  
Vol 71 (9) ◽  
pp. 1412-1424 ◽  
Author(s):  
Martin K. Ehlert ◽  
Alan Storr ◽  
Robert C. Thompson
Keyword(s):  
Electronic Spectroscopy ◽  
Indirect Evidence ◽  
Spectroscopic Studies ◽  
Zero Field ◽  
Zero Field Splitting ◽  
Magnetic Studies ◽  
One Dimensional ◽  
Heisenberg Type ◽  
Magnetic Modelling ◽  
Exchange Behaviour

The title compounds were prepared and characterized by X-ray powder diffraction, scanning electron microscopy, vibrational and electronic spectroscopy, and magnetic susceptibility measurements. Indirect evidence supports polymeric one-dimensional chain structures involving double pyrazolate bridges linking pseudo-tetrahedrally coordinated metal centres in all six compounds. The spectroscopic studies indicate a greater degree of distortion of the CoN4 chromophore from regular stereochemistry in the 4-substituted 3,5-dimethylpyrazolate complexes. The magnetic studies reveal anisotropy in the susceptibilities and the presence of significant antiferromagnetic exchange. Magnetic modelling employing both Ising and Heisenberg models suggests the exchange behaviour is probably of the Heisenberg type with zero-field splitting effects producing Ising-like exchange at low temperatures. The derived J values (~ −2 to −6 cm−1) have been used to qualitatively rank the magnitude of exchange as follows: 4-Hpz ≈ 3-Mepz [Formula: see text] 4-Medmpz ≈ 4-Cldmpz ≈ 4-Brdmpz ≈ 4-Hdmpz.

Crystal Structures and Magnetic or Photoluminescent Properties of Copper(II) and Zinc(II)-5-Sulfoisophthalate Coordination Polymers

2010 ◽  
Vol 63 (11) ◽  
pp. 1565 ◽  
Author(s):  
Qing-Yan Liu ◽  
Yu-Ling Wang ◽  
Zi-Yi Du ◽  
Zeng-Mei Shan ◽  
Er-Lei Yang ◽  
...  
Keyword(s):  
Magnetic Measurements ◽  
Variable Temperature ◽  
Fluorescence Emission ◽  
Zigzag Chain ◽  
Zero Field ◽  
Zero Field Splitting ◽  
Hydrothermal Conditions ◽  
Magnetic Studies ◽  
3D Network ◽  
Ferromagnetic Interactions

{[Cu4(µ3-OH)2(SIP)2(imz)2]·(H2O)2}n (1) and {[Zn3(µ2-OH2)2(SIP)2(phen)3(H2O)3]·(H2O)5}n (2) were obtained under hydrothermal conditions (SIP = 5-sulfoisophthalate, imz = imidazole, and phen = 1,10-phenanthroline). Compound 1 features a novel 3D network based on tetranuclear [Cu4(µ3-OH)2] secondary building unit; its topological structure is similar to that of rutile. Compound 2 is a 1D zigzag chain containing dinuclear [Zn2(µ2-OH2)2(phen)2] and mononuclear [Zn(phen)(H2O)] units. Variable-temperature magnetic studies reveal the existence of dominant ferromagnetic interactions within the tetranuclear copper(ii) cluster in compound 1. Further magnetic measurements indicate that compound 1 has the zero-field splitting parameters D = –0.29 cm–1 and E = 0.00052 cm–1, and g = 2.11 based on ST = 2. Compound 2 exhibits a blue fluorescence emission band at 458 nm on excitation at 391 nm, with a lifetime of 5.78 ns.

Magnetic and Electronic Properties of Three New Hetero-Bimetallic Coordination Frameworks [Ru2(O2CR)4][Au(CN)2] (R = Benzoic Acid, Furan-2-carboxylate, or Thiophen-2-carboxylate)

2014 ◽  
Vol 67 (11) ◽  
pp. 1607 ◽  
Author(s):  
Michael J. Murphy ◽  
Tony D. Keene ◽  
Jason R. Price ◽  
Deanna M. D'Alessandro ◽  
Cameron J. Kepert
Keyword(s):  
Electronic Properties ◽  
Chain Structure ◽  
Magnetic Behaviour ◽  
Zero Field ◽  
Dimensional Chain ◽  
Structure And Properties ◽  
Zero Field Splitting ◽  
One Dimensional ◽  
The One ◽  
Coordination Frameworks

The crystal structures and magnetic and electronic properties of three new hetero-bimetallic coordination frameworks, [Ru2(O2CR)4][Au(CN)2] (R = phenyl (1(Ph)), 2-furan (1(Furan)), and 2-thiophene (1(Thio)), have been characterised. Through variation of the functionalised carboxylate group, both the one-dimensional chain structure and properties of the frameworks have been systematically modulated. The magnetic behaviour for each framework has been modelled with a zero-field splitting model and the presence of weak inter-dimer coupling was assessed.

Antiferromagnetism and metamagnetism in 1,4-diazine and pyridine complexes of nickel(II)

1995 ◽  
Vol 73 (2) ◽  
pp. 275-283 ◽  
Author(s):  
Tom Otieno ◽  
Robert C. Thompson
Keyword(s):  
Magnetic Properties ◽  
Electronic Spectroscopy ◽  
Antiferromagnetic Coupling ◽  
Zero Field ◽  
Zero Field Splitting ◽  
Critical Fields ◽  
Scanning Calorimetry ◽  
Magnetic Exchange ◽  
Nickel Ions ◽  
Pyridine Complexes

Several nickel(II) complexes containing pyridine (py), pyrazine (pyz) or methylpyrazine (mepyz) have been synthesized and characterized by vibrational and electronic spectroscopy, differential scanning calorimetry, and magnetic susceptibility studies to cryogenic temperatures. A comparison of the magnetic properties of the polymeric diazine-bridged complexes, Ni(pyz)2X2 (X = Cl or NO3), Ni(pyz)(p-CH3C6H4SO3)2, Ni(mepyz)(NO3)2, and Ni(pyz)3(CH3SO3)2•CH3OH with those of the related monometallic systems, Ni(py)4X2 (X = Cl, p-CH3C6H4SO3 or CH3SO3) and Ni(mepyz)4(NO3)2•H2O provides evidence for weak antiferromagnetic coupling between metal centers mediated by bridging diazine ligands in the former group of compounds. The magnetic properties were analyzed employing a model for S = 1 which takes into account zero-field splitting and employs a molecular field term to account for weak magnetic exchange. The compounds Ni(pyz)Cl2 and Ni(py)Cl2 show metamagnetic behaviour with critical fields of 13 and 2 kOe, respectively, at 2 K. In these compounds nickel ions, linked in chains by bridging chlorides, exhibit intrachain ferromagnetic and interchain antiferromagnetic exchange. In Ni(pyz)Cl2 bridging pyrazine ligands are considered to provide the pathway for the antiferromagnetic coupling resulting in a high critical field. Keywords: nickel(II), pyrazine, pyridine, complexes, metamagnetism, antiferromagnetism.

scholarly journals Magnetostructural Studies on Zigzag One-Dimensional Coordination Polymers Formed by Tetraamidatodiruthenium(II,III) Paddlewheel Units Bridged by SCN Ligands

2019 ◽  
Vol 5 (3) ◽  
pp. 40 ◽  
Author(s):  
Sara Moreno-Da Silva ◽  
Patricia Delgado-Martínez ◽  
Miguel Cortijo ◽  
Rodrigo González-Prieto ◽  
José Luis Priego ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Coordination Polymers ◽  
Ground State ◽  
Magnetic Data ◽  
Zero Field ◽  
Donor Atom ◽  
Zero Field Splitting ◽  
One Dimensional ◽  
Linkage Isomerism ◽  
New Compounds

We report herein on three zigzag one-dimensional coordination polymers of {[Ru2(μ-NHOCR)4](μ-SCN)}n (R = o-Me-C6H4 (2), m-Me-C6H4 (3), p-Me-C6H4 (4)) formula. These new compounds have been obtained by reaction of the corresponding [Ru2(μ-NHOR)4(THF)2](BF4) complex with (NBu4)(SCN) under different synthetic conditions. The crystal structure of [Ru2(μ-NHOCC6H4-o-Me)4(THF)2](BF4) (1), 2 and 3 are presented. A cis-(2,2) arrangement of the amidate ligands of the [Ru2(μ-NHOCR)4]+ units is observed in all cases. Interestingly, the structures of 2 and 3 show linkage isomerism in alternated tetraamidatodiruthenium units whose axial positions are occupied by the same type of donor atom of the SCN ligands. This results in zigzag chains with a Ru-S-C angle of 98.97° and Ru-N-C angle of 169.36° in the case of 2 and 97.99° and 159.26°, respectively, in the case of 3. The magnetic data obtained for 2–4 are indicative of a σ2π4δ2(π*δ*)3 ground state (S = 3/2) and a large zero-field splitting (ZFS) in all cases (D = 54.57, 62.72 and 43.00 cm−1 for 2–4, respectively). Similar small antiferromagnetic interactions between diruthenium units (zJ = −0.93, −0.79 and −1.11 cm−1 for 2–4, respectively) are estimated for all the polymers, suggesting an analogous zigzag arrangement of the chains for 4.

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.

Spectroscopic studies and crystal structure of bis(N-2-pyridinylcarbonyl-2-pyridinecarboximidato) manganese(II) monohydrate: Zero-field splitting param

Polyhedron ◽  
1990 ◽  
Vol 9 (22) ◽  
pp. 2699-2704 ◽  
Author(s):  
Dolores Marcos ◽  
José-Vicente Folgado ◽  
Daniel Beltrán-Porter ◽  
Maria T. Do Prado-Gambardella ◽  
Sandra H. Pulcinelli ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Spectroscopic Studies ◽  
Zero Field ◽  
Zero Field Splitting ◽  
Field Splitting

Structural, magnetic, and spectroscopic studies of tetrakis(pyridine) complexes of iron(II) sulfonates

1986 ◽  
Vol 64 (3) ◽  
pp. 429-441 ◽  
Author(s):  
John S. Haynes ◽  
Steven J. Rettig ◽  
John R. Sams ◽  
Robert C. Thompson ◽  
James Trotter
Keyword(s):  
Magnetic Susceptibility ◽  
Least Squares ◽  
Ground State ◽  
Heavy Atom ◽  
Spectroscopic Studies ◽  
Zero Field ◽  
Zero Field Splitting ◽  
Scanning Calorimetry ◽  
Full Matrix ◽  
Space Group

The iron(II) complexes Fe(NC5H5)4(RSO3)2 where R = CF3, CH3, and p-CH3C6H4 have been prepared and their crystal structures determined by single crystal X-ray diffraction. Crystals of trans-bis(methanesulfonato-O)tetrakis(pyridine)iron(II) are monoclinic, a = 16.524(2), b = 9.1127(6), c = 18.684(2) Å, β = 109.903(6)°, Z = 4, space group Pn. The structure was solved by conventional heavy-atom methods and was refined by full-matrix least-squares procedures to R = 0.034 and Rw = 0.038 for 4243 reflections with I ≥ 3α(I). Crystals of trans-bis(trifluoromethanesulfonato-O)tetrakis(pyridine)iron(II) are monoclinic, a = 10.456(1), b = 9.2981(8), c = 14.625(2) Å, β = 96.372(6)°, Z = 2, space group Pn. Structure solved and refined as above to R = 0.036, and Rw = 0.037 for 1483 reflections with I ≥ 3σ(I). Crystals of trans-bis(p-toluenesulfonato-O)tetrakis(pyridine)iron(II)are orthorhombic, a = 40.818(2), b = 9.8722(6), c = 17.3544(7) Å, Z = 8, space group Fdd2. The structure was solved by Patterson and Fourier syntheses and was refined by full-matrix least-squares procedures to R = 0.030 and Rw = 0.032 for 1851 reflections with I ≥ 3σ(I). All three structures show discrete octahedral molecules with monodentate trans-coordinated sulfonate groups. Two crystallographically independent molecules are observed in the R = CH3 structure, the difference between them involving the orientation of the CH3SO3 groups with respect to the O—Fe—O vector. The FeN4O2 chromophore in each compound is a tetragonally compressed octahedron (approximate D4h, symmetry) with average Fe—N distances of 2.21, 2.23, and 2.24 Å and Fe—O distances of 2.11, 2.06, and 2.08 Å for theCF3, CH3, and p-CH3C6H4 derivatives, respectively. The compounds were studied using vibrational, electronic, and Mössbauer spectroscopic methods, magnetic susceptibility measurements, and differential scanning calorimetry. Quadrupole splitting values from Mössbauer spectra indicate a 5B2g ground state for all three compounds and magnetic susceptibility data (310–4.2 K) have been analyzed assuming this ground state, using both a crystal field and a zero-field splitting model.

A new one-dimensional thiocyanato-bridged bimetallic compound [Cu(en)2Mn(NCS)4(H2O)2]n. Synthesis, crystal structure, and magnetic properties

1998 ◽  
Vol 76 (7) ◽  
pp. 1102-1107 ◽  
Author(s):  
Hui-Zhong Kou ◽  
Dai-Zheng Liao ◽  
Peng Cheng ◽  
Zong-Hui Jiang ◽  
Shi-Ping Yan ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Antiferromagnetic Interaction ◽  
Zero Field ◽  
Spin Multiplicity ◽  
Zero Field Splitting ◽  
Field Splitting ◽  
Coordination Environment ◽  
One Dimensional ◽  
D Model ◽  
Splitting Effect

A bimetallic compound [Cu(en)2Mn(NCS)4(H2O)2]n (en = ethylenediamine) has been prepared and its structure determined. It crystallizes in space group , with a = 7.432(1), b = 7.492(1), c = 9.751(2) Å, α = 91.00(3)°, ß = 99.14(3)°, γ = 112.51(3)°, and Z = 1. The structure consists of one-dimensional chains in which alternating Mn(II) and Cu(II) ions are bridged by NCS ligands. The coordination environment is octahedral for Mn(II) and elongated octahedral for Cu(II). From magnetic susceptibility measurements the compound was found to exhibit a ground state of low-spin multiplicity. Comparison between theory and experimental has been made using 1-D model and taking into account the zero-field splitting effect. The decrease in chimT observed at low temperature for the compound is attributed to a dominant zero-field splitting of the single Mn(II) ions with a weak antiferromagnetic interaction superimposed between the Mn(II) ions via the NCS-Cu-SCN pathway within each chain. Key words: crystal structure, copper(II) complexes, manganese(II) complexes, thiocyanate bridges, bimetallic complexes.

Correlating the axial Zero Field Splitting with the slow magnetic relaxation in GdIII SIMs

2021 ◽  
Author(s):  
Júlia Mayans ◽  
Albert Escuer
Keyword(s):  
Magnetic Relaxation ◽  
Zero Field ◽  
Zero Field Splitting ◽  
Field Splitting ◽  
Slow Magnetic Relaxation

A possible relation between the value of the axial Zero Field Splitting and the occurrence of field-induced slow magnetic relaxation has been established for a new gadolinium(iii) compound.

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