Spin-labelled cyclometallated palladium complexes. EPR study of dynamic processes in coordination sphere

Kozhanov, Konstantin A.; Bubnov, M. P.; Abakumov, G. A.; Cherkasov, V. K.

doi:10.1016/j.jmr.2012.09.009

Cited by 8 publications

(3 citation statements)

References 23 publications

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“…There is an inhomogeneous broadening of sulfur components: the high-field component of the sulfur quartet appears more broadened than the low-field one. The measured value of the coupling constant on 33 S is 2.35 G. The hypothesis that this satellite splitting originates from the interaction with the 13 C nuclei (1.11%, S = 1/2, γ = 6.7283 × 10 4 rad G −1 s −1 ) is untenable, since in this case the value of HFS constant on this carbon should be of 7.06 G. Such a value seems to be too large, because coupling constants which are normally observed for 13 C–O atoms in semiquinones, are found in the range of 2.5–3.5 G [16–17]. …”

Section: Resultsmentioning

confidence: 99%

Protonated paramagnetic redox forms of di-o-quinone bridged with p-phenylene-extended TTF: A EPR spectroscopy study

Chalkov¹,

Cherkasov²,

Abakumov

et al. 2016

Beilstein J. Org. Chem.

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The chemical oxidation and reduction processes of deprotonated, direduced o-quinone-exTTF-o-quinone in protic solvents were studied by EPR spectroscopy. The formation of relatively stable paramagnetic protonated redox forms of the parent triad was very surprising. The character of spin-density distribution in the semiquinone–quinone and semiquinone–catechol redox forms indicates that the p-phenylene-extended tetrathiafulvalene connector provides a quite effective electronic communication channel between dioxolene coordination sites. It was found that the deprotonated, direduced o-quinone-exTTF-o-quinone is capable to reduction of the metal copper in solution. The radical anion species formed in this reaction exists in solution as a solvent-separated ion pair with a copper cation. A character of spin-density distribution in a radical anion species leads to the conclusion that the ligand corresponds to type III of the Robin–Day classification.

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Section: Resultsmentioning

confidence: 99%

Protonated paramagnetic redox forms of di-o-quinone bridged with p-phenylene-extended TTF: A EPR spectroscopy study

Chalkov¹,

Cherkasov²,

Abakumov

et al. 2016

Beilstein J. Org. Chem.

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show abstract

“…[18][19][20][21]24,25] The application of radical-ionic ligands as spin labels in metal complexes allows one to examine their composition, structure and dynamic processes by means of electron paramagnetic resonance spectroscopy. [26][27][28] On the other hand, redox ligands can be used as reservoirs of electrons for bond-making and bond-breaking reactions. They also able to support multi-electron transformations required to promote atom and group-transfer reactions.…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, o‐benzoquinone and o‐iminobenzoquinone complexes were found to demonstrate a spin‐crossover effect [18–23] and different types of inter‐ or intramolecular magnetic exchange interactions [18–21,24,25] . The application of radical‐ionic ligands as spin labels in metal complexes allows one to examine their composition, structure and dynamic processes by means of electron paramagnetic resonance spectroscopy [26–28] …”

Section: Introductionmentioning

confidence: 99%

Structural Changes in Five‐Coordinate Bromido‐bis(o‐iminobenzo‐semiquinonato)iron(III) Complex: Spin‐Crossover or Ligand‐Metal Antiferromagnetic Interactions?

et al. 2021

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Spin-crossover metal complexes represent important building blocks for a future generation of electronic and optical devices. Pentacoordinated o-iminosemiquinonate iron(III) complexes are able to demonstrate spin transitions between high spin (HS) and intermediate spin (IS) states under the influence of temperature or irradiation. Studied (Me imSQ) 2 FeBr sample showed a broad magnetic transition in the temperature region from 30 K to 300 K. Remarkably that observed behavior of magnetization can be interpreted with two controversial models. In the first model, the values of the effective magnetic moment at low temperature and high temperature can be assigned to the IS and HS magnetic moment of ferric ion coupled antiferromagnetically to radical anion ligands. In the second model, the metal spin on metal center remains IS in the whole temperature interval, while the mutual orientation of three magnetic moments in the molecule undergo changes due to exchange interactions. In this work we apply density functional theory and X-ray absorption spectroscopy to unravel the origin of magnetic properties of the complex. Temperature-induced changes of interatomic distances in the first coordination sphere support the second model. Such comprehensive analysis of the magnetic properties makes it possible to shed light on the nature of spin transitions in complexes of transition metals with open-shell ligands, which are often complicated by strong exchange interactions.

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Synthesis of o-benzoquinones annulated with 2-thioxo-1,3-dithiole-4,5-dithiolate fragment. Dioxolene ligands bearing non-planar geometry

et al. 2022

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Spin-labelled cyclometallated palladium complexes. EPR study of dynamic processes in coordination sphere

Cited by 8 publications

References 23 publications

Protonated paramagnetic redox forms of di-o-quinone bridged with p-phenylene-extended TTF: A EPR spectroscopy study

Protonated paramagnetic redox forms of di-o-quinone bridged with p-phenylene-extended TTF: A EPR spectroscopy study

Structural Changes in Five‐Coordinate Bromido‐bis(o‐iminobenzo‐semiquinonato)iron(III) Complex: Spin‐Crossover or Ligand‐Metal Antiferromagnetic Interactions?

Synthesis of o-benzoquinones annulated with 2-thioxo-1,3-dithiole-4,5-dithiolate fragment. Dioxolene ligands bearing non-planar geometry

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