The Structural and Magnetic Properties of First‐Row Transition‐Metal Dimers Containing Hydroxo, Substituted Hydroxo, and Halogen Bridges

Hodgson, Derek J.

doi:10.1002/9780470166208.ch4

Cited by 226 publications

(25 citation statements)

References 227 publications

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“…Alternatively, the data can be modeled by using the spin Hamiltonian for a dimer with two exchange-coupled V III ions, H ex = −2 J S 1 S 2 . The application of the van Vleck equation (Hodgson, 1975 ; Crawford et al, 1976 ) makes it possible to determine an analytical expression of the magnetic susceptibility (Equation S1) (Scaringe et al, 1977 ). The fitting parameters are g = 1.89(1) and J/k B = −7.8(1) K = 5.42 cm −1 .…”

Section: Resultsmentioning

confidence: 99%

“…The ferromagnetic coupling observed in complex 2' is quite unusual, as whilst in principle it should be possible to modify the electronic states of dichromium(III) systems such that the nature of the coupling changes from antiferromagnetic to ferromagnetic, very few examples of ferromagnetically coupled dinuclear chromium(III) compounds are known (Døssing, 2014 ). Following on from their seminal work establishing a linear relationship between the Cu-O-Cu bridging angle and the size of the magnetic coupling for a series of hydroxo-bridged copper(II) complexes (Hodgson, 1975 ; Crawford et al, 1976 ), Hodgson and Hatfield reported in 1977 what appears to be the first example of a ferromagnetically coupled chromium(III) dimer, sodium di-μ-hydroxo- bis [ bis (malonato)chromate(III)] pentahydrate (Scaringe et al, 1977 ). The exchange interaction for this doubly hydroxide bridged compound ( J = +1.08(2) cm −1 ) is small but consistent with weak ferromagnetic coupling between the Cr III centers.…”

Section: Resultsmentioning

confidence: 99%

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Di- and Tri-nuclear VIII and CrIII Complexes of Dipyridyltriazoles: Ligand Rearrangements, Mixed Valency and Ferromagnetic Coupling

et al. 2020

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The first dinuclear and trinuclear chromium(III) and dinuclear vanadium(III) complexes of N 4-R-substituted-3,5-di(2-pyridyl)-1,2,4-triazole (Rdpt) ligands have been prepared by solvothermal complexations under inert atmospheres, and characterized. The reactions of Cr III and V III with adpt (R = amino) resulted in deamination of the ligand and yielded the dinuclear doubly-triazolate bridged complexes [V III 2 (dpt −) 2 Cl 4 ] (1) and [Cr III 2 (dpt −) 2 Cl 4 ] (2). In the case of the Cr III complex 2 this bridging results in a rare example of ferromagnetic coupling for a dinuclear Cr III compound. DFT studies confirm that in 2 the ferromagnetic coupling pathways dominate over the antiferromagnetic pathways, whereas in 1 the reverse occurs, consistent with the observed overall antiferromagnetic coupling in that case. It was also found that the use of different additives in the reaction allows the nuclearity of the Cr III product to be manipulated, giving either the dinuclear system, or the first example of a trinuclear circular helicate for a Rdpt complex, [Cr III 3 (dpt) 3 Cl 6 ]•1¾MeCN•¼DCM (3). Reaction of N 4-pydpt (R = 4-pyridyl) with V III led to an unusual shift of the pyridyl substituent from N 4 to N 1 of the triazole, forming the ligand isomer N 1-pydpt, and giving a dinuclear doublytriazole bridged complex, [V III 2 (N 1-pydpt) 2 Cl 6 ]•2MeCN (4). Reaction with Cr III results in loss of the 4-pyridyl ring and a mixture of the di-and trinuclear complexes, 2 and 3. Interestingly, partial oxidation of the V III in dinuclear complex 4 to vanadyl V IV =O was identified by crystallographic analysis of partially oxidized single crystals, [(V IV O) 0.84 (V III) 1.16 (N 1-pydpt) 2 Cl 5.16 ]•0.84H 2 O•1.16MeCN (5).

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Di- and Tri-nuclear VIII and CrIII Complexes of Dipyridyltriazoles: Ligand Rearrangements, Mixed Valency and Ferromagnetic Coupling

et al. 2020

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“…3,5-di-tertbutylsalicylaldehyde was prepared from commercially available 2,4-di-tert-butylphenol according to the literature [25,26] Voltammetric experiments were performed using an Methrohm 694 VA Stand 693 processor with an electrochemical software GPES 4.9. A three electrode system was used: a 2-mm-size Pt disc working electrode, an Ag/AgCl reference electrode, and a Pt wire counter electrode.…”

Section: Methodsmentioning

confidence: 99%

Co(II) and Cu(II) Schiff base complexes of bis(N-(4-diethylamino-2-methylphenyl)-3,5-di-tert-butylsalicylaldimine): Electrochemical and X-ray structural study

et al. 2008

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Copper(II) and cobalt(II) complexes of salicylaldimine obtained by the condensation of N,N-diethyl-2-methyl-1,4-phenylenediamine with 3,5-di-tert-butyl-2-hydroxybenzaldehyde have been synthesized and characterized by elemental analyses, magnetic susceptibility measurements, cyclic voltammetry, and FT-IR and UV-Vis spectroscopy. The molecular structure of the title copper(II) complex was determined by the single crystal X-ray diffraction technique. The Cu(II) center is coordinated by four atoms of the donor set in a compressed tetrahedral trans-[N 2 O 2 ] environment, which can be essentially ascribed to the presence of bulky fragments of the ligand. The computed bond valences of the copper verify +2 oxidation state and indicate that the copper bonds, in particular Cu-N bonds, are elongated due to steric effects from bulky substituents in the ligands, N-(4-diethylamino-2-methylphenyl). Intermolecular C-HÁÁÁp interactions leading to centrosymmetric synthons serve to stabilize periodic organization of the molecules.

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“…The strength of the antiferromagnetic coupling in OR-bridged dicopper(II) complexes depends on the Cu II -O-Cu II angle. [49][50][51] The computed struc-…”

Section: Dft Calculationsmentioning

confidence: 99%

Copper(II) Coordination Chemistry of Westiellamide and Its Imidazole, Oxazole, and Thiazole Analogues

Comba

Gahan

Haberhauer

et al. 2008

Chemistry A European J

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The Structural and Magnetic Properties of First‐Row Transition‐Metal Dimers Containing Hydroxo, Substituted Hydroxo, and Halogen Bridges

Cited by 226 publications

References 227 publications

Di- and Tri-nuclear VIII and CrIII Complexes of Dipyridyltriazoles: Ligand Rearrangements, Mixed Valency and Ferromagnetic Coupling

Di- and Tri-nuclear VIII and CrIII Complexes of Dipyridyltriazoles: Ligand Rearrangements, Mixed Valency and Ferromagnetic Coupling

Co(II) and Cu(II) Schiff base complexes of bis(N-(4-diethylamino-2-methylphenyl)-3,5-di-tert-butylsalicylaldimine): Electrochemical and X-ray structural study

Copper(II) Coordination Chemistry of Westiellamide and Its Imidazole, Oxazole, and Thiazole Analogues

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