Tetranuclear complexes in molecular magnetism: Targeted synthesis, high-field EPR and pulsed-field magnetization

Chaudhuri, Phalguni; Kataev, V.; Büchner, B.; Klauß, H.‐H.; Kersting, Berthold; Meyer, Franc

doi:10.1016/j.ccr.2009.03.024

Cited by 39 publications

(29 citation statements)

References 90 publications

(91 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…3. A transfer of the spectral weight to lower magnetic field at low temperatures revealed a negative axial magnetic anisotropy of the molecule (parameter D < 0) in both complexes [11,4], in accord with the self-orientation of the particles during measurements in a high magnetic field and the presence of an "easy" axis of anisotropy. …”

Section: Hf-esr Spectrasupporting

confidence: 56%

“…The g-factor is approximated with an isotropic value, as is usually found for Cr(III) ions in distorted octahedral coordination. [11,[13][14][15][16] Here, we assume the values of the g-factors and ∆ parameters obtained from the resonance branches, shown in Figs. 1 and 2.…”

Section: Discussionmentioning

confidence: 99%

“…From the arithmetic mean of the slopes of the resonance branches, g-factor could be obtained as g = (h/µ B )∂ν/∂H res = 1.98. [11] Here, h is the Planck constant and µ B is the Bohr magneton. The left resonance branch (red color) has the y-intercept ∆ = 31 GHz ≈ 1.5 K, that corresponds to a first estimate of the magnetic anisotropy gap, i.e.…”

Section: Hf-esr Spectramentioning

confidence: 99%

See 2 more Smart Citations

Magnetic Anisotropy of Cr(III) Ions in Polymeric Oxalate Complexes as Revealed by HF-ESR Spectroscopy

et al. 2015

Self Cite

View full text Add to dashboard Cite

Two new Cr(III) paramagnetic polymeric complexes:, where phen = 1,10-phenanthroline and bpy = 2,2 ′ -bipyridine, have been studied by high field-high frequency electron spin resonance (HF-ESR) spectroscopy. From the oriented powder spectra, recorded in the frequency range 83 − 332 GHz in magnetic fields up to 16 T, the spin-Hamiltonian parameters, g, D and E, have been obtained. Both chromium complexes have a small negative (easy axis) magnetic anisotropy |D| < 1 K. CrPhen complex is biaxial, i.e. besides axial D, there is also significant rhombic zero-field splitting (ZFS) parameter, E. Contrary to CrPhen, CrBpy complex is uniaxial, but described by two sets of axial ZFS parameters. Despite very similar crystallographic structures of both complexes, HF-ESR spectroscopy resolved the existence of two magnetically inequivalent Cr(III)

show abstract

Section: Hf-esr Spectrasupporting

confidence: 56%

Section: Discussionmentioning

confidence: 99%

Section: Hf-esr Spectramentioning

confidence: 99%

See 1 more Smart Citation

Magnetic Anisotropy of Cr(III) Ions in Polymeric Oxalate Complexes as Revealed by HF-ESR Spectroscopy

et al. 2015

Self Cite

View full text Add to dashboard Cite

show abstract

“…Data obtained in the pH range 10.0−7.0 were treated with the HYPERQUAD program 33 giving a value of log β = 32.40(4) for the reaction 3Cu 2+ + 2L1 + CO 3 2-⇆ [Cu 3 (H −1 L1) 2 (CO 3 )] 2+ . The distribution diagram for this system (see Figure S10) provides evidence that the ternary complex predominates from pH 10.0 to 7.5, which indicates an important ability for fixing CO 2 .…”

Section: ■ Introductionmentioning

confidence: 99%

Intermolecular Binding Modes in a Novel [1 + 1] Condensation 1H-Pyrazole Azamacrocycle: A Solution and Solid State Study with Evidence for CO₂ Fixation

et al. 2013

View full text Add to dashboard Cite

The synthesis of a novel cyclophane (L1) consisting of a 1H-pyrazole moiety linked through methylene groups to a 1,5,9,13-tetraazadecane chain is described. As far as we know, this is one of the first reported syntheses of a [1 + 1] condensation 1H-pyrazole azamacrocyclic ligand. The crystal structures of the complexes [Cu2(H(H(-1)L1))(H(-1)L1)](ClO4)3·3.75H2O (1) and ([Cu2(H(H(-1)L1))(0.5)(H(-1)L1)(1.5)]2(ClO4)3Br2·4.2H2O (2) show that Cu(2+) coordination leads to formation of 2:2 Cu(2+):L dinuclear dimeric complexes in which the 1H-pyrazole units lose a proton behaving as bis(monodentate) bridging ligands. Unlike previously reported complexes of [2 + 2] pyrazole azamacrocycles, the pyrazolate units in 1 are pointing outward from the macrocyclic cavity to bind the Cu(2+) ions. Inner coordination with formation of 1:1 Cu(2+):L complexes is however observed in [1 + 1] pyridine azamacrocycles as shown by the crystal structure here presented of the complex [CuL2](ClO4)2 (3). Crystals of [Cu3(H(-1)L1)2(CO3)(H2O)](ClO4)2·8H2O (4) grown by evaporating aqueous solution at pH 9 containing Cu(2+) and L1 in 3:2 molar ratio show the presence of a further Cu(2+) coordinated to the two free amine groups found in structures 1 and 2. The metal ion fills its coordination sphere capturing atmospheric CO2 as a η(1),η(2)-bidentate carbonate anion placed in the equatorial position and an axial water molecule. pH-metric data, UV-vis spectroscopic data, EPR measurements, and HR-ESI-MS data support that the outer coordination mode with formation of 2:2 dinuclear dimeric and 3:2 trinuclear complexes is preserved in aqueous solution.

show abstract

“…These methods have already been proven as powerful tools for the investigation of magnetic interactions and spin states of molecular Ni(II) complexes. [35][36][37] …”

Section: Introductionmentioning

confidence: 99%

Interplay of Magnetic Exchange Interactions and NiSNi Bond Angles in Polynuclear Nickel(II) Complexes

Krupskaya¹,

Alfonsov²,

Parameswaran³

et al. 2010

ChemPhysChem

Self Cite

View full text Add to dashboard Cite

The ability of bridging thiophenolate groups (RS -) to transmit magnetic exchange interactions between paramagnetic Ni(II) ions has been examined. Specific attention was paid to complexes with large Ni-SR-Ni angles. For this purpose, dinuclear [Ni2Land trinuclear [Ni3L 2 (OAc)2][BPh4]2 (3), where H2L 1 and H2L 2 represent 24-membered macrocyclic amino-thiophenol ligands, were prepared and fully characterized by IR-and UV-vis spectroscopy, X-ray crystallography, static magnetization M measurements and high-field electron spin resonance (HF-ESR). The dinuclear complex 2 has a central N3Ni2(-S)2(-OAc)Ni2N3 core with a mean Ni-S-Ni angle of 92°. The macrocycle L 2 supports a trinuclear complex 3, with distorted octahedral N2O2S2 and N2O3S coordination environments for one central and two terminal Ni(II) ions, respectively. The Ni-S-Ni angles are at 132.8° and 133.5°. We find that the variation of the bond angles has a very strong impact on the magnetic properties of the Ni complexes. In the case of the Ni2-complex, temperature T and magnetic field B dependencies of M reveal a ferromagnetic coupling J = -29 cm -1 between two Ni(II) ions (H = JS1S2). HF-ESR measurements yield a negative axial magnetic anisotropy (D < 0) which implies a bistable (easy axis) magnetic ground state. In contrast, for the Ni3-complex we find an appreciable antiferromagnetic coupling J' = 97 cm -1 between the Ni(II) ions and a positive axial magnetic anisotropy (D > 0) which implies an easy plane situation.

show abstract

Tetranuclear complexes in molecular magnetism: Targeted synthesis, high-field EPR and pulsed-field magnetization

Cited by 39 publications

References 90 publications

Magnetic Anisotropy of Cr(III) Ions in Polymeric Oxalate Complexes as Revealed by HF-ESR Spectroscopy

Magnetic Anisotropy of Cr(III) Ions in Polymeric Oxalate Complexes as Revealed by HF-ESR Spectroscopy

Intermolecular Binding Modes in a Novel [1 + 1] Condensation 1H-Pyrazole Azamacrocycle: A Solution and Solid State Study with Evidence for CO₂ Fixation

Interplay of Magnetic Exchange Interactions and NiSNi Bond Angles in Polynuclear Nickel(II) Complexes

Contact Info

Product

Resources

About

Tetranuclear complexes in molecular magnetism: Targeted synthesis, high-field EPR and pulsed-field magnetization

Cited by 39 publications

References 90 publications

Magnetic Anisotropy of Cr(III) Ions in Polymeric Oxalate Complexes as Revealed by HF-ESR Spectroscopy

Magnetic Anisotropy of Cr(III) Ions in Polymeric Oxalate Complexes as Revealed by HF-ESR Spectroscopy

Intermolecular Binding Modes in a Novel [1 + 1] Condensation 1H-Pyrazole Azamacrocycle: A Solution and Solid State Study with Evidence for CO2 Fixation

Interplay of Magnetic Exchange Interactions and NiSNi Bond Angles in Polynuclear Nickel(II) Complexes

Contact Info

Product

Resources

About

Intermolecular Binding Modes in a Novel [1 + 1] Condensation 1H-Pyrazole Azamacrocycle: A Solution and Solid State Study with Evidence for CO₂ Fixation