Magnetically bistable cobalt-dioxolene complexes with a tetradentate N-donor base

Chegerev, M. G.; Корчагин, Денис В.; Шилов, Г. В.; Efimov, Nikolay N.; Starikov, А. G.; Piskunov, A. V.; Chernyshev, A. V.; Bulgakov, Aleksei N; Palii, Andrew; Алдошин, С. М.

doi:10.1039/d2dt02874c

Cited by 5 publications

(2 citation statements)

References 78 publications

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“…This methodology was shown to provide a good reproduction of the energetic characteristics and magnetic properties of magnetically bistable transition metal compounds, in particular cobalt complexes with redox-active ligands. 17,18,27,33,38,[56][57][58] Since the calculated (Mulliken, Lowdin, NBO, Hirshfeld) charges do not provide reliable conclusions about the oxidation state of the central ion in complexes with redox-active ligands, 59 the isomers of complexes 1a, 2a and 3a were assigned to the corresponding electronic states on the basis of spin density distribution. Geometry optimisations were performed with the crystal structure of 1a, 2a and 3a as the starting geometry.…”

Section: Density Functional Theory (Dft) Calculationsmentioning

confidence: 99%

Tuning valence tautomerism in a family of dinuclear cobalt complexes incorporating a conjugated bridging bis(dioxolene) ligand with weak communication

Fischer,

Janetzki,

M. Zahir

et al. 2024

Dalton Trans.

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Section: Density Functional Theory (Dft) Calculationsmentioning

confidence: 99%

Tuning valence tautomerism in a family of dinuclear cobalt complexes incorporating a conjugated bridging bis(dioxolene) ligand with weak communication

Fischer,

Janetzki,

M. Zahir

et al. 2024

Dalton Trans.

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“…In this regard, structurally variable Co( ii ) complexes with temperature-controlled dynamic bonds and isomeric Co( ii ) complexes provide well-suited platforms to explore the influence of the coordination number and geometry on the magnetic properties. 31–34 When the same coordination geometry, for example trigonal prismatic coordination, is maintained, modifications of counter ions, donor atoms and remote substituents of the ligands are effective approaches for the exploration of magneto-structural correlations. In this work, we implemented the replacement of counter anions, altering the environment around the high-spin Co( ii ) center for [CoL N8 ] 2+ cations (L N8 = 1,4,7,10-tetrakis(2-pyridinemethyl)-1,4,7,10-tetraaza-cyclododecane), which yielded the two cobalt( ii ) complexes [Co(L N8 )](BPh 4 ) 2 ·C 4 H 10 O ( 1-BPh 4 ) and [Co(L N8 )](NO 3 ) 2 ·CH 3 CN ( 2-NO 3 ).…”

Section: Introductionmentioning

confidence: 99%

Effects of weak intramolecular interactions and distortions from trigonal prismatic coordination on the magnetic properties of zero-field Co(ii) single-ion magnets

Zhang,

Zhou,

Huang

et al. 2024

Inorg. Chem. Front.

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Tuning Valence Tautomerism in Dinuclear Cobalt Complexes by Modulating Communication in the Bridging Ligand

Janetzki,

Gransbury,

Gable

et al. 2024

Eur J Inorg Chem

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The capability of bis(dioxolene) ligands to access multiple redox states makes them ideal candidates to tune the electronic properties of metal complexes, for example to achieve valence tautomerism (VT). In this study, a family of dinuclear cobalt complexes have been isolated with the bridging bis(dioxolene) thean− ligand in the cat2−‐cat2−, cat2−‐SQ●− and SQ●−‐SQ●− states (cat2− = catecholate, SQ●− = semiquinonate): [{CoIII(tpa)}2(theacat‐cat)](PF6)2 (1), [{CoIII(tpa)}2(theacat‐SQ)](PF6)3 (2), and [{CoIII(tpa)}2(theaSQ‐SQ)](PF6)4 (3) (theaH4 = 2,3,6,7‐tetrahydroxy‐9,10‐dimethyl‐9,10‐dihydro‐9,10‐ethanoanthracene, tpa = tris(2‐pyridylmethyl)amine). Multi‐technique analysis confirmed that 1, 2 and 3 adopt low spin (LS)‐CoIII containing {CoIII‐cat‐cat‐CoIII}, {CoIII‐cat‐SQ‐CoIII} and {CoIII‐SQ‐SQ‐CoIII} states, respectively. Compound 1 undergoes thermally‐induced {CoIII‐cat‐cat‐CoIII} ⇌ {CoIII‐cat‐SQ‐CoII} VT in the solid‐ and solution‐states above 300 K, involving high spin‐CoII. This interconversion is contrary to expectations, as tpa typically stabilizes low spin‐CoIII‐cat. Compound 2 is mixed‐valence class II‐III, indicating a localized electronic structure, with electron transfer faster than the EPR and solvent rearrangement timescales, but slower than the IR timescale. Compound 3 exhibits strong antiferromagnetic exchange. The overlap between the dioxolene π‐orbitals in thean− increases the accessibility of the cat2−‐SQ●− state, resulting in VT for 1. This study demonstrates that thean− can be isolated in multiple oxidation states in metal complexes, promising for applications in magnetic materials.

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Magnetically bistable cobalt-dioxolene complexes with a tetradentate N-donor base

Cited by 5 publications

References 78 publications

Tuning valence tautomerism in a family of dinuclear cobalt complexes incorporating a conjugated bridging bis(dioxolene) ligand with weak communication

Tuning valence tautomerism in a family of dinuclear cobalt complexes incorporating a conjugated bridging bis(dioxolene) ligand with weak communication

Effects of weak intramolecular interactions and distortions from trigonal prismatic coordination on the magnetic properties of zero-field Co(ii) single-ion magnets

Tuning Valence Tautomerism in Dinuclear Cobalt Complexes by Modulating Communication in the Bridging Ligand

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