Salicylaldoxime-Supported Nona- and Tetrametallic Fe&lt;sup&gt;III&lt;/sup&gt; Cages

Mason, Kevin; Prescimone, Alessandro; Schau‐Magnussen, Magnus; Piligkos, Stergios; Tasker, Peter A.; Brechin, Euan K.

doi:10.2174/1877944111303020002

Cited by 5 publications

(3 citation statements)

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“…which gave J =‐32.6 cm −1 with g fixed to 2.0 and 4.5 % molar percentage of mononuclear Fe III ( S =5/2) paramagnetic impurity. Comparison of the magnetic interactions in 3 with those observed in a similar [Fe 4 ] cluster with oximato and alkoxo bridges reveals stronger antiferromagnetic exchange in the former, possibly attributed to the smaller Fe−N−O−Fe torsion angles which favor antiferromagnetic exchange …”

Section: Resultsmentioning

confidence: 86%

“…Distorted [Fe 4 ] squares with similar bridging are quite rare in 3d metal ions chemistry. The only [Fe 4 ] examples reported so far are the two clusters [Fe 4 (R‐sao) 4 (hmp) 4 ] (R‐sao=the dianion of salicylaldoxime derivatives with R=Et, Ph, and hmp=the monoanion of 2‐(hydroxymethyl)pyridine) with oximato and μ 2 ‐alkoxo bridges from R‐sao 2− and hmp − respectively, and [Fe 4 F 4 (Ph‐sao) 4 (py) 4 ] with oximato and μ 2 ‐F bridges; none of them contains oximato and μ 2 ‐OH − bridges like the cation in 3 . As far as we know other examples have been reported only in Ni II chemistry .…”

Section: Resultsmentioning

confidence: 99%

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Iron(III) complexes with 2-pyridyl oxime ligands: Synthesis, structural and spectroscopic characterization, and magnetic studies

et al. 2016

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Reactions of FeIII sources with 2‐pyridyl oxime ligands, pyC(R)NOH (R=H, Me, Ph), afforded the trinuclear oxo‐centered complexes (NH4)[Fe3O(LH)6(H2O)3](ClO4)8 ⋅MeOH⋅1.14H2O (1⋅ MeOH⋅1.14H2O) and [Fe3O{pyC(H)NO)(PhCO2)6(H2O)]⋅MeCN (2⋅MeCN), the tetranuclear complex [Fe4(OH)4{pyC(Me)NO}4(H2O)4] (ClO4)4⋅3Me2CO⋅H2O (3⋅3Me2CO⋅H2O), and the hexanuclear complexes [Fe6(OH)6{pyC(Me)NO}6(H2O)6](ClO4)6⋅8Me2CO⋅2H2O (4⋅8Me2CO⋅2H2O), [Fe6(OH)6{pyC(Me)NO}6(MeCONH2)6](ClO4)6⋅2MeCN⋅H2O (5⋅2MeCN⋅H2O), [Fe6(OH)6 {pyC(Ph)NO}6(H2O)6](ClO4)6⋅4.4Me2CO ⋅1.6Et2O (6⋅4.4Me2CO ⋅1.6Et2O) and [Fe6(OH)6{pyC(Ph)NO}6(MeOH)6](ClO4)5.5(OH)0.5⋅MeOH⋅0.5H2O (7⋅MeOH ⋅0.5H2O), where LH is the zwitterion anionic form of 2‐pyridinecarboxylic acid (picolinic acid). Complex 3 can be described as inverse 12‐metallacrown‐4, whereas 4–7 can be described as inverse 18‐metallacrowns‐6 and represent the first examples of iron(III) metallacyclic clusters with pyC(R)NOH (R=H, Me, Ph) ligands. Complexes 3 and 6 were characterized by Mössbauer spectroscopy and magnetic susceptibility measurements, while complex 2 was characterized by EPR spectroscopy.

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Section: Resultsmentioning

confidence: 86%

Section: Resultsmentioning

confidence: 99%

Iron(III) complexes with 2-pyridyl oxime ligands: Synthesis, structural and spectroscopic characterization, and magnetic studies

et al. 2016

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“…Deprotonation of both hydroxyl groups is also possible in phenolic oximes, often leading to the formation of polynuclear complexes, particularly with higher oxidation state metal ions, for example, Mn [ 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 ] and Fe [ 7 , 14 , 16 , 17 , 18 , 19 , 20 ].…”

Section: Introductionmentioning

confidence: 99%

From Gas Phase Observations to Solid State Reality: The Identification and Isolation of Trinuclear Salicylaldoximato Copper Complexes

et al. 2022

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Conditions have been identified in which phenolic aldoximes and ketoximes of the types used in commercial solvent extraction processes can be doubly deprotonated and generate polynuclear Cu complexes with lower extractant:Cu molar ratios than those found in commercial operations. Electrospray mass spectrometry has provided an insight into the solution speciation in extraction experiments and has identified conditions to allow isolation and characterization of polynuclear Cu-complexes. Elevation of pH is effective in enhancing the formation of trinuclear complexes containing planar {Cu3-μ3-O}4+ or {Cu3-μ3-OH}5+ units. DFT calculations suggest that such trinuclear complexes are more stable than other polynuclear species. Solid structures of complexes formed by a salicylaldoxime with a piperidino substituent ortho to the phenolic OH group (L9H2) contain two trinuclear units in a supramolecular assembly, {[Cu3OH(L9H)3(ClO4)](ClO4)} 2, formed by H-bonding between the central {Cu3-μ3-OH}5+ units and oxygen atoms in the ligands of an adjacent complex. Whilst the lower ligand:Cu molar ratios provide more efficient Cu-loading in solvent extraction processes, the requirement to raise the pH of the aqueous phase to achieve this will make it impractical in most commercial operations because extraction will be accompanied by the precipitation (as oxyhydroxides) of Fe(III) which is present in significant quantities in feed solutions generated by acid leaching of most Cu ores.

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Single-Molecule-Magnet Fe^II₄Fe^III₂ and Antiferromagnetic Fe^III₄ Coordination Clusters

et al. 2019

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Supported by endogenous (part of the ligand, in-built) phenoxo bridges provided by the ligand 2,6-bis[{{(5-bromo-2-hydroxybenzyl)}{(2-(pyridylethyl)}amino}methyl]-4-methylphenol) (H3L), in its deprotonated form, exogenous (not part of the ligand, externally added or generated) oxo-/hydroxo- and acetato-bridged [FeII 4FeIII 2(O)2(O2CMe)4(L)2]·4Et2O (1) and [FeIII 4(OH)2(O2CMe)3(L)2](ClO4)·3MeCN·2H2O (2) coordination clusters have been synthesized and structurally characterized. Complexes 1 and 2 have μ4-O and μ3-OH bridges, respectively. Magnetic studies on 1 reveal slow magnetic relaxation below 2 K. Both in-phase (χ′ M) and out-of-phase (χ″M) magnetic susceptibility were found to be frequency dependent. This is typical of a single-molecule magnet (SMM) with τ0 = 1.9(2) × 10–7 s–1 and E a = 5.1(3) cm–1. Assuming that E a corresponds to the energy splitting of the ground spin state (S = 2) by the zero-filed-splitting (zfs), E a = 4|D| (D is the axial zfs parameter), D ≈ – 1.3 cm–1 could be estimated. For 2, three types of magnetic interactions are observed: J A = −56.5(3), J B = −71.6(4), and J C = +4.5(2) cm–1. Considering the observed structural parameters, the magnetic behavior for both of the coordination clusters 1 and 2 has been rationalized.

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Salicylaldoxime-Supported Nona- and Tetrametallic Fe<sup>III</sup> Cages

Abstract: (7), stabilised with salicylaldoxime (saoH 2 ) or derivatised salicylaldoxime (R-saoH 2 ) ligands in conjunction with either 1,4,7-triazocyclononane (tacn), 2-(hydroxymethyl)pyridine (hmpH) or 2,6-pyridinedimethanol (pdmH 2 ) are discussed.

Cited by 5 publications

References 55 publications

Iron(III) complexes with 2-pyridyl oxime ligands: Synthesis, structural and spectroscopic characterization, and magnetic studies

Iron(III) complexes with 2-pyridyl oxime ligands: Synthesis, structural and spectroscopic characterization, and magnetic studies

From Gas Phase Observations to Solid State Reality: The Identification and Isolation of Trinuclear Salicylaldoximato Copper Complexes

Single-Molecule-Magnet Fe^II₄Fe^III₂ and Antiferromagnetic Fe^III₄ Coordination Clusters

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Salicylaldoxime-Supported Nona- and Tetrametallic Fe<sup>III</sup> Cages

Abstract: (7), stabilised with salicylaldoxime (saoH 2 ) or derivatised salicylaldoxime (R-saoH 2 ) ligands in conjunction with either 1,4,7-triazocyclononane (tacn), 2-(hydroxymethyl)pyridine (hmpH) or 2,6-pyridinedimethanol (pdmH 2 ) are discussed.

Cited by 5 publications

References 55 publications

Iron(III) complexes with 2-pyridyl oxime ligands: Synthesis, structural and spectroscopic characterization, and magnetic studies

Iron(III) complexes with 2-pyridyl oxime ligands: Synthesis, structural and spectroscopic characterization, and magnetic studies

From Gas Phase Observations to Solid State Reality: The Identification and Isolation of Trinuclear Salicylaldoximato Copper Complexes

Single-Molecule-Magnet FeII4FeIII2 and Antiferromagnetic FeIII4 Coordination Clusters

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Single-Molecule-Magnet Fe^II₄Fe^III₂ and Antiferromagnetic Fe^III₄ Coordination Clusters