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.

Synthesis and Characterization of the Heptanuclear [MnIII 6 CoIII]3+ Triplesalen Complex: Evidence for Exchange Pathways Involving Low-spin CoIII

2010 ◽  
Vol 65 (3) ◽  
pp. 295-303 ◽  
Author(s):  
Erich Krickemeyer ◽  
Veronika Hoeke ◽  
Anja Stammler ◽  
Jürgen Schnack ◽  
Hartmut Bögge ◽  
...  
Keyword(s):  
Exchange Interaction ◽  
Metal Ion ◽  
Magnetic Measurements ◽  
Variable Temperature ◽  
Molecular Structures ◽  
Magnetic Data ◽  
Zero Field ◽  
Central Metal ◽  
Zero Field Splitting ◽  
Isotropic Exchange

The reaction of the tert-butyl-substituted triplesalen ligand H6talent-Bu2 with MnII(OAc)2・ 4H2O and K3[CoIII(CN)6] results in the formation of the heptanuclear complex [{(talent-Bu2 )- (MnIII(MeOH))3}2{CoIII(CN)6}](PF6)2(OAc)・11MeOH ([MnIII6 CoIII](PF6)2(OAc)・11MeOH, 1 ・11MeOH), which has been characterized by FT-IR spectroscopy, elemental analysis, ESI-MS, single-crystal X-ray diffraction, and magnetic measurements. The molecular structure of the [MnIII6 CoIII]3+ complex is closely related to the already published analogs [MnIII6CrIII]3+ and [MnIII6 FeIII]3+. Variable-temperature variable-field and μeff vs. T magnetic data have been analyzed in detail by full-matrix diagonalization of the appropriate spin-Hamiltonian consisting of isotropic exchange, zero-field splitting, and Zeeman interaction, taking into account the relative orientation of the D tensors. This allowed a careful inspection of the MnIII-MnIII exchange interaction involving a diamagnetic central metal ion. A satisfactory reproduction of the magnetic data required the incorporation not only of an exchange interaction between the MnIII ions belonging to one triplesalen half unit, but also of an exchange coupling between MnIII ions belonging to different triplesalen subunits. Satisfactory reproduction of the experimental data has been obtained for the parameter set J1 = −(0.50±0.04) cm−1, J2 = +(0.05±0.02) cm−1, and D = −(2.5±0.5) cm−1. A detailed analysis of the J1 coupling taking into account the molecular structures of the three available heptanuclear complexes [MnIII6MIII]3+ (M = Cr, Fe, Co) indicates that the exchange interaction between the MnIII ions belonging to the same triplesalen subunit involves not only an exchange pathway through the central phloroglucinol unit but also an exchange pathway through the central metal ion.

Iron(II) complexes containing thiophene-substituted “bispicen” ligands — Spin-crossover, ligand rearrangements, and ferromagnetic interactions

2010 ◽  
Vol 88 (9) ◽  
pp. 954-963 ◽  
Author(s):  
Haojin Cheng ◽  
Brandon Djukic ◽  
Hilary A. Jenkins ◽  
Serge I. Gorelsky ◽  
Martin T. Lemaire
Keyword(s):  
Magnetic Properties ◽  
Density Functional ◽  
Spin Crossover ◽  
Variable Temperature ◽  
Density Functional Theory Calculations ◽  
Zero Field ◽  
Zero Field Splitting ◽  
Magnetic Analysis ◽  
Ferromagnetic Chain ◽  
Ferromagnetic Interactions

The synthesis and characterization of three new tetradentate “bispicen-type” ligands containing a substituted thiophene heterocycle are described [2,5-thienyl substituents = H (7), Ph (8), or 2-thienyl (9)]. Iron(II) bis(thiocyanate) coordination complexes containing 7–9 were prepared, and the electronic and variable-temperature magnetic properties of complexes containing 7 (10) and 9 (12) are described. Complex 10 features a gradual and incomplete spin crossover in the solid state, and 12 remains high-spin over the entire temperature range. Complex 11 is extremely unstable and rearranges to another iron(II) complex (13), which was structurally characterized. The temperature-dependent magnetic properties of 13 are described as a one-dimensional ferromagnetic chain, with interchain antiferromagnetic interactions and (or) zero-field splitting dominant at low temperatures. The magnetic analysis is corroborated by the molecular packing and density functional theory calculations, which suggest intermolecular interactions between coordinated thiocyanate ligands bearing a significant spin density.

scholarly journals [CrIII8NiII6]n+ Heterometallic Coordination Cubes

2021 ◽  
Author(s):  
Helen O'Connor ◽  
Sergio Sanz ◽  
Aaron Scott ◽  
Mateusz Pitak ◽  
Wim Klooster ◽  
...  
Keyword(s):  
Magnetic Susceptibility ◽  
Direct Current ◽  
Zero Field ◽  
Modular Approach ◽  
Zero Field Splitting ◽  
Heterometallic Clusters ◽  
Related Family ◽  
Weak Exchange ◽  
Ferromagnetic Interactions ◽  
Weak Ferromagnetic

Three new heterometallic [CrIII8NiII6] coordination cubes of formulae [CrIII8NiII6L24(H2O)12](NO3)12 (1), [CrIII8NiII6L24(MeCN)7(H2O)5](ClO4)12 (2) and [CrIII8NiII6L24Cl12] (3) (where HL = 1-(4-pyridyl)butane-1,3-dione), were synthesised using the paramagnetic metalloligand [CrIIIL3] and the corresponding NiII salt. The magnetic skeleton of each capsule describes a face-centred cube in which the eight CrIII and six NiII ions occupy the eight vertices and six faces of the structure, respectively. Direct current magnetic susceptibility measurements on (1) reveal weak ferromagnetic interactions between the CrIII and NiII ions, with JCr-Ni = +0.045 cm-1 . EPR spectra are consistent with weak exchange, being dominated by the zero-field splitting of the CrIII ions. Excluding wheel-like structures, examples of large heterometallic clusters containing both CrIII and NiII ions are rather rare, and we demonstrate that the use of metalloligands with predictable bonding modes allows for a modular approach to building families of related polymetallic complexes. Compounds (1)-(3) join the previously published, structurally related family of [MIII8MII6] cubes, where MIII = Cr, Fe and MII = Cu, Co, Mn, Pd. <br>

scholarly journals Ligand-Field Calculations on Pseudo-Tetragonal Ni(II) Compounds

1977 ◽  
Vol 32 (6) ◽  
pp. 632-640 ◽  
Author(s):  
A. Vermaas ◽  
W. L. Groeneveld ◽  
J. Reedijk
Keyword(s):  
Magnetic Measurements ◽  
Magnetic Saturation ◽  
Ligand Field ◽  
Zero Field ◽  
Spin Orbit Coupling ◽  
Zero Field Splitting ◽  
Energy Parameters ◽  
Ligand Field Spectra ◽  
D Values ◽  
Single Set

Abstract Magnetic susceptibility, magnetic saturation, ligand field and EPR measurements are reported for the compounds Ni(5-methyl pyrazole) 4X2, (X = Cl, Br, I). All data are interpreted using ligand-field calculations, yielding parameters D q, D s, D t, B, C, g∥, g⊥,D, ζ∥, ζ⊥, and k.All data fit with a single set of parameters. The zero-field splittings and g values are determined from the magnetic measurements, whereas the excited state splittings are determined from the ligand-field spectra.In studying the relation between the zero-field splitting of the Ni(II) ion and both the spinorbit coupling and spectroscopic energy parameters, a description using an anisotropic spin-orbit coupling gave the most reliable fit.In addition, known ligand-field spectra and D values of Ni (pyrazole) 4X2, (X = Cl, Br, I) were considered. The derived energy parameters of the corresponding pyrazole and 5-methyl pyrazole compounds are very similar.

scholarly journals pH-dependent forms of the ferryl haem in myoglobin peroxide analysed by variable-temperature magnetic circular dichroism

1989 ◽  
Vol 261 (2) ◽  
pp. 515-522 ◽  
Author(s):  
N Foote ◽  
P M A Gadsby ◽  
C Greenwood ◽  
A J Thomson
Keyword(s):  
Circular Dichroism ◽  
Magnetic Circular Dichroism ◽  
Variable Temperature ◽  
Zero Field ◽  
Zero Field Splitting ◽  
Zero Field Splitting Parameter ◽  
Varied Temperature ◽  
Splitting Parameter ◽  
Catalytic Cycles ◽  
Circular Dichroïsm

The reaction product of myoglobin and H2O2 exists in two different forms according to the external pH. Varied-temperature magnetic-circular dichroism (m.c.d.) spectroscopy demonstrates that both contain the oxyferryl ion Fe(IV) = O. Alkaline myoglobin peroxide has often been used as a model for oxidized intermediates in the catalytic cycles of haem-containing peroxidases, but absorption and m.c.d. spectra show that the acid form is much more closely related to species such as horeradish peroxidase Compound II. The differences are tentatively ascribed to ionization of the proximal histidine ligand in alkaline myoglobin peroxide. It is also shown that the m.c.d. method allows an estimate of the zero-field splitting parameter of both forms, values of D = 28.0 +/- 3 cm-1 and 35.0 +/- 5 cm-1 being obtained for the alkaline and acid forms respectively.

scholarly journals [CrIII8NiII6]n+ Heterometallic Coordination Cubes

Molecules ◽  
2021 ◽  
Vol 26 (3) ◽  
pp. 757
Author(s):  
Helen M. O’Connor ◽  
Sergio Sanz ◽  
Aaron J. Scott ◽  
Mateusz B. Pitak ◽  
Wim T. Klooster ◽  
...  
Keyword(s):  
Magnetic Susceptibility ◽  
Direct Current ◽  
Zero Field ◽  
Modular Approach ◽  
Zero Field Splitting ◽  
Heterometallic Clusters ◽  
Related Family ◽  
Weak Exchange ◽  
Ferromagnetic Interactions ◽  
Weak Ferromagnetic

Three new heterometallic [CrIII8NiII6] coordination cubes of formulae [CrIII8NiII6L24(H2O)12](NO3)12 (1), [CrIII8NiII6L24(MeCN)7(H2O)5](ClO4)12 (2), and [CrIII8NiII6L24Cl12] (3) (where HL = 1-(4-pyridyl)butane-1,3-dione), were synthesised using the paramagnetic metalloligand [CrIIIL3] and the corresponding NiII salt. The magnetic skeleton of each capsule describes a face-centred cube in which the eight CrIII and six NiII ions occupy the eight vertices and six faces of the structure, respectively. Direct current magnetic susceptibility measurements on (1) reveal weak ferromagnetic interactions between the CrIII and NiII ions, with JCr-Ni = + 0.045 cm−1. EPR spectra are consistent with weak exchange, being dominated by the zero-field splitting of the CrIII ions. Excluding wheel-like structures, examples of large heterometallic clusters containing both CrIII and NiII ions are rather rare, and we demonstrate that the use of metalloligands with predictable bonding modes allows for a modular approach to building families of related polymetallic complexes. Compounds (1)–(3) join the previously published, structurally related family of [MIII8MII6] cubes, where MIII = Cr, Fe and MII = Cu, Co, Mn, Pd.

A ZnII-MOF Assembled by Triazine-Based Polycarboxylate and 4,4′-Bipy: Structure, Fluorescent Properties, and Water Vapour Adsorption

2018 ◽  
Vol 71 (11) ◽  
pp. 863
Author(s):  
Lu Feng ◽  
Hong Zhou
Keyword(s):  
Water Vapour ◽  
Metal Organic Framework ◽  
Fluorescence Emission ◽  
Fluorescent Properties ◽  
Hydrothermal Conditions ◽  
X Ray ◽  
3D Network ◽  
Vapour Adsorption ◽  
Metal Organic ◽  
Water Vapour Adsorption

A new flexible triazine-based polycarboxylate metal–organic framework, {[Zn4(TTHA)(4, 4′-bipy)2(OH)2(H2O)]·H2O}n (1), H6TTHA = 1,3,5-triazine-2,4,6-triamine hexaacetic acid, has been synthesised under hydrothermal conditions and structurally characterised by X-ray diffraction, infrared spectroscopy, elemental analysis, and X-ray single-crystal diffraction. Structural studies indicate that 1 exhibits a 3D network with a 4,6-connected topology, formed by the interconnection of tetranuclear units and the ligands. The fluorescence emission properties of 1 and the free ligands were investigated in the solid state at room temperature. Moreover, the fluorescence lifetime (τ) and quantum yield (Φf) were obtained to further characterise the fluorescence properties. In addition, the water vapour adsorption of 1 was first studied for H6TTHA based complexes, which shows a general water adsorption capacity.

Crystal structures, magnetic properties, and absorption spectra of nickel(II) thiocyanato complexes: a comparison of different coordination geometries

2003 ◽  
Vol 81 (11) ◽  
pp. 1168-1179 ◽  
Author(s):  
Bruno Larue ◽  
Lan-Tâm Tran ◽  
Dominique Luneau ◽  
Christian Reber
Keyword(s):  
Magnetic Properties ◽  
Crystal Structures ◽  
Absorption Spectra ◽  
Exchange Coupling ◽  
Molecular Magnetism ◽  
Zero Field ◽  
Zero Field Splitting ◽  
Space Group ◽  
Trigonal Bipyramidal ◽  
Ferromagnetic Interactions

Thiocyanatonickel(II) compounds with composition {(AsPh4)2[Ni(NCS)4]} 1, {(Cat)[Ni(NCS)4]} 2, {(AsPh4)4 [Ni2(NCS)8]} 3, {(Cat)2[Ni2(NCS)8]·2CH3NO2} 4, and {(Et4N)4[Ni(NCS)6]} 5 (Cat2+ = (p-xylylenebis(triphenyphosphonium))2+) were prepared. The crystal structures of compounds 1, 3, and 4 were determined. Compound 1 crystallizes in the monoclinic C2/c space group with a = 22.761(2) Å, b = 15.055(1) Å, c = 15.054(1) Å, β = 108.915(1)°, V = 4879.9(6) Å3, and Z = 4. Compound 3 crystallizes in the triclinic P–1 space group with a = 11.2183(6) Å, b = 14.2551(8) Å, c = 16.629(1) Å, α = 79.326(1)°, β = 73.605(1)°, γ = 75.496(1)°, V = 2451.0(2) Å3, Z = 2. Compound 4 crystallizes in the monoclinic P21/n space group with a = 13.1148(9) Å, b = 27.128(2) Å, c = 14.882(1) Å, β = 114.056(2)°, V = 4834.8(6) Å3, Z = 4. The magnetic properties of compounds 1-4 were studied over the 2–300 K temperature range. Compounds 1 and 2 with monometallic [Ni(NCS)4]2– complex units have similar magnetic properties, in agreement with nickel(II) ions in pseudo-tetrahedral environments. Compounds 3 and 4 with bimetallic [Ni2(NCS)8]4– complex units exhibit magnetic properties, which are indicative of Ni(II)–Ni(II) ferromagnetic interactions with zero-field splitting effects caused by the pseudo-square-pyramidal or pseudo-trigonal-bipyramidal coordination environments of the nickel(II) ion in compounds 3 and 4, respectively. The structures and magnetic results for all compounds are correlated with NIR–UV–vis absorption spectra.Key words: nickel(II) thiocyanato complexes, crystal structures, paramagnetism, molecular magnetism, exchange coupling, absorption spectroscopy.

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.

A variable temperature EPR study of Mn2+-doped NH4Cl0.9I0.1 single crystal at 170GHz: Zero-field splitting parameter and its absolute sign

2005 ◽  
Vol 174 (2) ◽  
pp. 265-269 ◽  
Author(s):  
Sushil K. Misra ◽  
Serguei I. Andronenko ◽  
Prem Chand ◽  
Keith A. Earle ◽  
Sergei V. Paschenko ◽  
...  
Keyword(s):  
Single Crystal ◽  
Variable Temperature ◽  
Zero Field ◽  
Zero Field Splitting ◽  
Field Splitting ◽  
Zero Field Splitting Parameter ◽  
Splitting Parameter
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