Old ligands with new coordination chemistry: Linear trinuclear mixed oxidation state cobalt(III/II/III) complexes and their mononuclear “ligand” cobalt(III) complexes featuring 2-pyridyloximates

Stamatatos, Theocharis C.; Bell, Aidan; Cooper, Paul; Terzis, Aris; Raptopoulou, Catherine P.; Heath, Sarah L.; Winpenny, Richard E. P.; Perlepes, Spyros P.

doi:10.1016/j.inoche.2005.03.004

Cited by 48 publications

(9 citation statements)

References 29 publications

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“…As changing the base or a solvent used in the reaction did not give the expected results, we have changed the starting metal(II) salts, by choosing the corresponding perchlorates. − It turned out that a light beige precipitate obtained after heating the mixture of 2-acetylpyridineoxime and phenylboronic acid with nickel(II) perchlorate and NaHCO 3 in ethanol medium is a pure target nickel(II) complex (according to NMR data). The same synthetic approach also gave phenylboron-capped cobalt(II), zinc(II), and manganese(II) tris-acetylpyridineoximates in high yields (Scheme ).…”

Section: Resultsmentioning

confidence: 99%

Trigonal Prismatic Tris-pyridineoximate Transition Metal Complexes: A Cobalt(II) Compound with High Magnetic Anisotropy

et al. 2017

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High magnetic anisotropy is a key property of paramagnetic shift tags, which are mostly studied by NMR spectroscopy, and of single molecule magnets, for which magnetometry is usually used. We successfully employed both these methods in analyzing magnetic properties of a series of transition metal complexes, the so-called clathrochelates. A cobalt complex was found to be both a promising paramagnetic shift tag and a single molecule magnet because of it having large axial magnetic susceptibility tensor anisotropy at room temperature (22.5 × 10 m mol) and a high effective barrier to magnetization reversal (up to 70.5 cm). The origin of this large magnetic anisotropy is a negative value of zero-field splitting energy that reaches -86 cm according to magnetometry and NMR measurements.

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Section: Resultsmentioning

confidence: 99%

Trigonal Prismatic Tris-pyridineoximate Transition Metal Complexes: A Cobalt(II) Compound with High Magnetic Anisotropy

et al. 2017

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“…The average Co–N bond distances of Co2 are in the ranges of 1.948–1.959 Å (<1.960 Å) and 1.893–1.094 Å (<2.077 Å), which indicates that Co2 is in the 3+ oxidation state, and the Co–O bond distances of Co1 are found to be in the range of 2.081–2.152 Å, suggesting a 2+ oxidation state for Co1. − The Co–O bond distances of Co2 are shorter than those of Co1 (Table S1). Thus, 1 contains a mixed-valence cobalt(II)/cobalt(III) trinuclear complex.…”

Section: Results and Discussionmentioning

confidence: 98%

Nitrogen-Doped Mixed-Phase Cobalt Nanocatalyst Derived from a Trinuclear Mixed-Valence Cobalt(III)/Cobalt(II) Complex for High-Performance Oxygen Evolution Reaction

et al. 2021

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Because of a continuous increase in energy demands and environmental concerns, a focus has been on the design and construction of a highly efficient, low-cost, environmentally friendly, and noble-metal free electrocatalyst for energy technology. Herein we report facile synthesis of the mixed-valence trinuclear cobalt complex 1 by the reaction of 2-amino-1-phenylethanol and CoCl2·6H2O in methanol as the solvent at room temperature. Further, 1 was reduced by using aqueous N2H4 as a simple reducing agent, followed by calcination at 300 °C for 3 h, yielding a nitrogen-doped mixed phase cobalt [β-Co(OH)2 and CoO] nanocatalyst (N@MPCoNC). Both 1 and N@MPCoNC were characterized by various physicochemical techniques. Moreover, 1 was authenticated by single-crystal X-ray diffraction studies. The hybrid N@MPCoNC reveals a unique electronic and morphological structure, offering a low overpotential of 390 mV for a stable current density of 10 mA cm–2 with high durability. This N@MPCoNC showed excellent electrocatalytic as well as photocatalytic activity for oxygen evolution reaction compared to 1.

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“…Complexes 1 and 2 join a small family of structurally characterized homo- [17, 18, 21] and heterometallic [22, 23] Co complexes featuring pao − as ligand. Many years ago Blackmore and Magee [24, 25] and Grant and Magee [26] studied the reactions between 2-pyridinealdoxime and various Co II sources under a variety of reaction conditions.…”

Section: Methodsmentioning

confidence: 99%

“…Reaction schemes involving di-2-pyridyl ketone oxime, dpkoxH ( Figure 1 ), and various Co carboxylate sources led [ 16 ] to the first mixed-valence Co(II,III), inverse 12-metallacrown-4 complexes, namely, [Co 2 II Co 2 III (OR) 2 (O 2 CR′) 2 (dpkox) 4 S 2 ]X 2 (R = H, CH 3 ; R ′ = CH 3 , C 6 H 5 , (CH 3 ) 3 ; S = solvent; X = ClO 4 , PF 6 ). The use of phenyl 2-pyridyl ketone oxime, phpkoxH ( Figure 1 ), methyl 2-pyridyl ketone oxime, MepaoH ( Figure 1 ), and 2-pyridinealdoxime, paoH ( Figure 1 ) in Co carboxylate chemistry yielded [ 17 ] the trinuclear, mixed-valence, carboxylate-free Co(II,III) complexes [Co 3 (phpkox) 6 ](PF 6 ) 2 , [Co 3 (Mepao) 6 ](ClO 4 ) 2 , and [Co 3 (pao) 6 ](ClO 4 ) 2 . The core of these complexes has an open-topology comprising one Co II center and two Co III ions.…”

Section: Introductionmentioning

confidence: 99%

Use of the 2‐Pyridinealdoxime/N,N^′‐Donor Ligand Combination in Cobalt(III) Chemistry: Synthesis and Characterization of Two Cationic Mononuclear Cobalt(III) Complexes

Konidaris

Raptopoulou²,

Psycharis³

et al. 2010

Bioinorganic Chemistry and Applications

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The use of 2-pyridinealdoxime (paoH)/N,N′-donor ligand (L-L) “blend” in cobalt chemistry has afforded two cationic mononuclear cobalt(III) complexes of the general type [Co(pao)2(L-L)]+, where L-L = 1,10-phenanthroline (phen) and 2,2′-bipyridine (bpy). The CoCl2/paoH/L-L (1 : 2 : 1) reaction system in MeOH gives complexes [CoIII(pao)2(phen)]Cl·2H2O (1·2H2O) and [CoIII(pao)2(bpy)]Cl·1.5MeOH (2·1.5MeOH). The structures of the complexes were determined by single-crystal X-ray crystallography. The CoIII ions are six-coordinate, surrounded by three bidentate chelating ligands, that is, two pao− and one phen or bpy. The deprotonated oxygen atom of the pao− ligand remains uncoordinated and participates in hydrogen bonding with the solvate molecules. IR data of the complexes are discussed in terms of the nature of bonding and the known structures.

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Old ligands with new coordination chemistry: Linear trinuclear mixed oxidation state cobalt(III/II/III) complexes and their mononuclear “ligand” cobalt(III) complexes featuring 2-pyridyloximates

Cited by 48 publications

References 29 publications

Trigonal Prismatic Tris-pyridineoximate Transition Metal Complexes: A Cobalt(II) Compound with High Magnetic Anisotropy

Trigonal Prismatic Tris-pyridineoximate Transition Metal Complexes: A Cobalt(II) Compound with High Magnetic Anisotropy

Nitrogen-Doped Mixed-Phase Cobalt Nanocatalyst Derived from a Trinuclear Mixed-Valence Cobalt(III)/Cobalt(II) Complex for High-Performance Oxygen Evolution Reaction

Use of the 2‐Pyridinealdoxime/N,N^′‐Donor Ligand Combination in Cobalt(III) Chemistry: Synthesis and Characterization of Two Cationic Mononuclear Cobalt(III) Complexes

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Old ligands with new coordination chemistry: Linear trinuclear mixed oxidation state cobalt(III/II/III) complexes and their mononuclear “ligand” cobalt(III) complexes featuring 2-pyridyloximates

Cited by 48 publications

References 29 publications

Trigonal Prismatic Tris-pyridineoximate Transition Metal Complexes: A Cobalt(II) Compound with High Magnetic Anisotropy

Trigonal Prismatic Tris-pyridineoximate Transition Metal Complexes: A Cobalt(II) Compound with High Magnetic Anisotropy

Nitrogen-Doped Mixed-Phase Cobalt Nanocatalyst Derived from a Trinuclear Mixed-Valence Cobalt(III)/Cobalt(II) Complex for High-Performance Oxygen Evolution Reaction

Use of the 2‐Pyridinealdoxime/N,N′‐Donor Ligand Combination in Cobalt(III) Chemistry: Synthesis and Characterization of Two Cationic Mononuclear Cobalt(III) Complexes

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Use of the 2‐Pyridinealdoxime/N,N^′‐Donor Ligand Combination in Cobalt(III) Chemistry: Synthesis and Characterization of Two Cationic Mononuclear Cobalt(III) Complexes