Cobalt complexes with redox-active anthraquinone-type ligands
Three anthraquinone-type multidentate ligands, HL1-3 (HL = 2-R-1H-anthra[1,2-d]imidazole6,11-dione, HL1; R = (2-pyridyl), HL2; R = (4,6-dimethyl-2-pyridyl), HL3; R = (6-methoxy-2pyridyl)), were prepared, and their complexation behaviour were investigated. Three bis-chelate cobalt complexes with the...
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| Format: | Article |
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Royal Society of Chemistry
2018
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| Online Access: | https://eprints.nottingham.ac.uk/52301/ |
| _version_ | 1848798694389841920 |
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| author | Shiga, Takuya Kumamaru, Rina Newton, Graham N. Oshio, Hiroki |
| author_facet | Shiga, Takuya Kumamaru, Rina Newton, Graham N. Oshio, Hiroki |
| author_sort | Shiga, Takuya |
| building | Nottingham Research Data Repository |
| collection | Online Access |
| description | Three anthraquinone-type multidentate ligands, HL1-3 (HL = 2-R-1H-anthra[1,2-d]imidazole6,11-dione, HL1; R = (2-pyridyl), HL2; R = (4,6-dimethyl-2-pyridyl), HL3; R = (6-methoxy-2pyridyl)), were prepared, and their complexation behaviour were investigated. Three bis-chelate cobalt complexes with the formula [CoII(L1-3)2].n(solv.) (1, 2, and 3 for HL1, HL2, and HL3, respectively), in which the ligands adopted tridentate binding modes, were synthesized and structurally characterized by single-crystal X-ray analyses. Electrochemical studies of 1-3 in CH2Cl2 reveal three reversible redox waves, assigned to ligand and cobalt-centred processes. Further complexes were obtained in which HL1 adopted a bidentate binding mode, stabilising the mono-chelate [CoII(HL1)(NO3)2(DMF)2] (4) species and tris-chelate [CoIII(L1)3] (5) complex in which the cobalt ion was in its 3+ state. The electrochemical properties of complex 5 were investigated in DMF, and the Co(II)/Co(III) redox couple was found to have negatively shifted compared to that of complex 1, while the ligand-based processes became irreversible. Tridentate chelation is found to stabilise the anthraquinone ligands and unlocks their redox multi-stability. |
| first_indexed | 2025-11-14T20:23:50Z |
| format | Article |
| id | nottingham-52301 |
| institution | University of Nottingham Malaysia Campus |
| institution_category | Local University |
| last_indexed | 2025-11-14T20:23:50Z |
| publishDate | 2018 |
| publisher | Royal Society of Chemistry |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | nottingham-523012020-05-04T19:41:45Z https://eprints.nottingham.ac.uk/52301/ Cobalt complexes with redox-active anthraquinone-type ligands Shiga, Takuya Kumamaru, Rina Newton, Graham N. Oshio, Hiroki Three anthraquinone-type multidentate ligands, HL1-3 (HL = 2-R-1H-anthra[1,2-d]imidazole6,11-dione, HL1; R = (2-pyridyl), HL2; R = (4,6-dimethyl-2-pyridyl), HL3; R = (6-methoxy-2pyridyl)), were prepared, and their complexation behaviour were investigated. Three bis-chelate cobalt complexes with the formula [CoII(L1-3)2].n(solv.) (1, 2, and 3 for HL1, HL2, and HL3, respectively), in which the ligands adopted tridentate binding modes, were synthesized and structurally characterized by single-crystal X-ray analyses. Electrochemical studies of 1-3 in CH2Cl2 reveal three reversible redox waves, assigned to ligand and cobalt-centred processes. Further complexes were obtained in which HL1 adopted a bidentate binding mode, stabilising the mono-chelate [CoII(HL1)(NO3)2(DMF)2] (4) species and tris-chelate [CoIII(L1)3] (5) complex in which the cobalt ion was in its 3+ state. The electrochemical properties of complex 5 were investigated in DMF, and the Co(II)/Co(III) redox couple was found to have negatively shifted compared to that of complex 1, while the ligand-based processes became irreversible. Tridentate chelation is found to stabilise the anthraquinone ligands and unlocks their redox multi-stability. Royal Society of Chemistry 2018-06-21 Article PeerReviewed Shiga, Takuya, Kumamaru, Rina, Newton, Graham N. and Oshio, Hiroki (2018) Cobalt complexes with redox-active anthraquinone-type ligands. Dalton Transactions, 47 (23). pp. 7804-7811. ISSN 1477-9234 http://pubs.rsc.org/en/content/articlelanding/2018/dt/c8dt00586a#!divAbstract doi:10.1039/C8DT00586A doi:10.1039/C8DT00586A |
| spellingShingle | Shiga, Takuya Kumamaru, Rina Newton, Graham N. Oshio, Hiroki Cobalt complexes with redox-active anthraquinone-type ligands |
| title | Cobalt complexes with redox-active anthraquinone-type ligands |
| title_full | Cobalt complexes with redox-active anthraquinone-type ligands |
| title_fullStr | Cobalt complexes with redox-active anthraquinone-type ligands |
| title_full_unstemmed | Cobalt complexes with redox-active anthraquinone-type ligands |
| title_short | Cobalt complexes with redox-active anthraquinone-type ligands |
| title_sort | cobalt complexes with redox-active anthraquinone-type ligands |
| url | https://eprints.nottingham.ac.uk/52301/ https://eprints.nottingham.ac.uk/52301/ https://eprints.nottingham.ac.uk/52301/ |