Triggering of Valence Tautomeric Transitions in Dioxolene-Based Cobalt Complexes Influenced by Ligand Substituents, Co-ligands, and Anions
We report the multistep synthesis of the 1,1′-(piperazine-1,4-diyl)bis(N,N-bis(pyridin-2-ylmethyl)methanamine)(<b>L<sup>tpbap</sup></b>) octadentate ligand, which, in combination with the known 3,5-di-tert-butylcatechol (<b>3,5-dbcat</b>), allowed the preparation...
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2022-09-01
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author | Sriram Sundaresan Marcel Diehl Luca M. Carrella Eva Rentschler |
author_facet | Sriram Sundaresan Marcel Diehl Luca M. Carrella Eva Rentschler |
author_sort | Sriram Sundaresan |
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description | We report the multistep synthesis of the 1,1′-(piperazine-1,4-diyl)bis(N,N-bis(pyridin-2-ylmethyl)methanamine)(<b>L<sup>tpbap</sup></b>) octadentate ligand, which, in combination with the known 3,5-di-tert-butylcatechol (<b>3,5-dbcat</b>), allowed the preparation of two di-nuclear cobalt complexes [Co<sub>2</sub>(<b>L<sup>tpbap</sup></b>)(<b>3,5-dbcat</b>)<sub>2</sub>](SO<sub>4</sub>)·5.5MeOH·2H<sub>2</sub>O (<b>3a</b>) and [Co<sub>2</sub>(<b>L<sup>tpbap</sup></b>)(<b>3,5-dbcat</b>)<sub>2</sub> ](ClO<sub>4</sub>)<sub>2</sub>·1.5H<sub>2</sub>O (<b>3b</b>). We also report the synthesis of two mono-nuclear cobalt complexes [Co(<b>3,5-dbsq</b>)(<b>3,5-dbcat</b>)(4-Mepip)<sub>2</sub>] (<b>1</b>) with 4-Mepip being 4-methylpiperidine and (Hpip)[Co(<b>tbcat</b>)<sub>2</sub>(pip)<sub>2</sub>]·CH<sub>3</sub>CN (<b>2</b>) where Hpip denotes a piperidinium cation and <b>tbcat</b> is the <i>tetra</i>-bromocatechol ligand. The obtained complexes were characterized by single-crystal X-ray crystallography, SQUID magnetometry, and IR spectroscopy. The structure of the crystalline material in all the cases was determined at 173 K. The magnetic properties of all complexes were measured between 2 and 380 K. The magnetic data clearly show that mono-nuclear complex <b>1</b> and di-nuclear complex <b>3a</b> exhibit valence tautomerism with onset around 300 K and 370 K, respectively, whereas the other two complexes <b>2</b> and <b>3b</b> remain unchanged over the measured temperature range. |
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spelling | doaj.art-f50e8f12c8ff4e5db0d0e10415d309fb2023-11-23T17:28:02ZengMDPI AGMagnetochemistry2312-74812022-09-018910910.3390/magnetochemistry8090109Triggering of Valence Tautomeric Transitions in Dioxolene-Based Cobalt Complexes Influenced by Ligand Substituents, Co-ligands, and AnionsSriram Sundaresan0Marcel Diehl1Luca M. Carrella2Eva Rentschler3Department Chemie, Johannes-Gutenberg-Universität Mainz, Duesbergweg 10–14, 55128 Mainz, GermanyDepartment Chemie, Johannes-Gutenberg-Universität Mainz, Duesbergweg 10–14, 55128 Mainz, GermanyDepartment Chemie, Johannes-Gutenberg-Universität Mainz, Duesbergweg 10–14, 55128 Mainz, GermanyDepartment Chemie, Johannes-Gutenberg-Universität Mainz, Duesbergweg 10–14, 55128 Mainz, GermanyWe report the multistep synthesis of the 1,1′-(piperazine-1,4-diyl)bis(N,N-bis(pyridin-2-ylmethyl)methanamine)(<b>L<sup>tpbap</sup></b>) octadentate ligand, which, in combination with the known 3,5-di-tert-butylcatechol (<b>3,5-dbcat</b>), allowed the preparation of two di-nuclear cobalt complexes [Co<sub>2</sub>(<b>L<sup>tpbap</sup></b>)(<b>3,5-dbcat</b>)<sub>2</sub>](SO<sub>4</sub>)·5.5MeOH·2H<sub>2</sub>O (<b>3a</b>) and [Co<sub>2</sub>(<b>L<sup>tpbap</sup></b>)(<b>3,5-dbcat</b>)<sub>2</sub> ](ClO<sub>4</sub>)<sub>2</sub>·1.5H<sub>2</sub>O (<b>3b</b>). We also report the synthesis of two mono-nuclear cobalt complexes [Co(<b>3,5-dbsq</b>)(<b>3,5-dbcat</b>)(4-Mepip)<sub>2</sub>] (<b>1</b>) with 4-Mepip being 4-methylpiperidine and (Hpip)[Co(<b>tbcat</b>)<sub>2</sub>(pip)<sub>2</sub>]·CH<sub>3</sub>CN (<b>2</b>) where Hpip denotes a piperidinium cation and <b>tbcat</b> is the <i>tetra</i>-bromocatechol ligand. The obtained complexes were characterized by single-crystal X-ray crystallography, SQUID magnetometry, and IR spectroscopy. The structure of the crystalline material in all the cases was determined at 173 K. The magnetic properties of all complexes were measured between 2 and 380 K. The magnetic data clearly show that mono-nuclear complex <b>1</b> and di-nuclear complex <b>3a</b> exhibit valence tautomerism with onset around 300 K and 370 K, respectively, whereas the other two complexes <b>2</b> and <b>3b</b> remain unchanged over the measured temperature range.https://www.mdpi.com/2312-7481/8/9/109Valence-Tautomercobaltdi-nucleardi-oxolene |
spellingShingle | Sriram Sundaresan Marcel Diehl Luca M. Carrella Eva Rentschler Triggering of Valence Tautomeric Transitions in Dioxolene-Based Cobalt Complexes Influenced by Ligand Substituents, Co-ligands, and Anions Magnetochemistry Valence-Tautomer cobalt di-nuclear di-oxolene |
title | Triggering of Valence Tautomeric Transitions in Dioxolene-Based Cobalt Complexes Influenced by Ligand Substituents, Co-ligands, and Anions |
title_full | Triggering of Valence Tautomeric Transitions in Dioxolene-Based Cobalt Complexes Influenced by Ligand Substituents, Co-ligands, and Anions |
title_fullStr | Triggering of Valence Tautomeric Transitions in Dioxolene-Based Cobalt Complexes Influenced by Ligand Substituents, Co-ligands, and Anions |
title_full_unstemmed | Triggering of Valence Tautomeric Transitions in Dioxolene-Based Cobalt Complexes Influenced by Ligand Substituents, Co-ligands, and Anions |
title_short | Triggering of Valence Tautomeric Transitions in Dioxolene-Based Cobalt Complexes Influenced by Ligand Substituents, Co-ligands, and Anions |
title_sort | triggering of valence tautomeric transitions in dioxolene based cobalt complexes influenced by ligand substituents co ligands and anions |
topic | Valence-Tautomer cobalt di-nuclear di-oxolene |
url | https://www.mdpi.com/2312-7481/8/9/109 |
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