Synthesis and electronic structure determination of uranium(vi) ligand radical complexes.
Saved in:
| Title: | Synthesis and electronic structure determination of uranium(vi) ligand radical complexes. |
|---|---|
| Authors: | Herasymchuk, Khrystyna1, Chiang, Linus1, Hayes, Cassandra E.1, Brown, Matthew L.1, Ovens, Jeffrey S.1, Patrick, Brian O.2, Leznoff, Daniel B.1, Storr, Tim1 |
| Source: | Dalton Transactions: An International Journal of Inorganic Chemistry. 8/21/2016, Vol. 45 Issue 31, p12576-12586. 11p. |
| Subjects: | Ligands (Chemistry), Cations, Amines, Radicals (Chemistry), Oxidation |
| Abstract: | Pentagonal bipyramidal uranyl (UO22+) complexes of salen ligands, N,N′-bis(3-tert-butyl-(5R)-salicylidene)-1,2-phenylenediamine, in which R = tBu (1a), OMe (1b), and NMe2 (1c), were prepared and the electronic structure of the one-electron oxidized species [1a–c]+ were investigated in solution. The solid-state structures of 1a and 1b were solved by X-ray crystallography, and in the case of 1b an asymmetric UO22+ unit was found due to an intermolecular hydrogen bonding interaction. Electrochemical investigation of 1a–c by cyclic voltammetry showed that each complex exhibited at least one quasi-reversible redox process assigned to the oxidation of the phenolate moieties to phenoxyl radicals. The trend in redox potentials matches the electron-donating ability of the para-phenolate substituents. The electron paramagnetic resonance spectra of cations [1a–c]+ exhibited gav values of 1.997, 1.999, and 1.995, respectively, reflecting the ligand radical character of the oxidized forms, and in addition, spin–orbit coupling to the uranium centre. Chemical oxidation as monitored by ultraviolet-visible-near-infrared (UV-vis-NIR) spectroscopy afforded the one-electron oxidized species. Weak low energy intra-ligand charge transfer (CT) transitions were observed for [1a–c]+ indicating localization of the ligand radical to form a phenolate/phenoxyl radical species. Further analysis using density functional theory (DFT) calculations predicted a localized phenoxyl radical for [1a–c]+ with a small but significant contribution of the phenylenediamine unit to the spin density. Time-dependent DFT (TD-DFT) calculations provided further insight into the nature of the low energy transitions, predicting both phenolate to phenoxyl intervalence charge transfer (IVCT) and phenylenediamine to phenoxyl CT character. Overall, [1a–c]+ are determined to be relatively localized ligand radical complexes, in which localization is enhanced as the electron donating ability of the para-phenolate substituents is increased (NMe2 ＞ OMe ＞ tBu). [ABSTRACT FROM AUTHOR] |
| Copyright of Dalton Transactions: An International Journal of Inorganic Chemistry is the property of Royal Society of Chemistry and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
| Database: | Engineering Source |
| FullText | Text: Availability: 0 |
|---|---|
| Header | DbId: egs DbLabel: Engineering Source An: 117156362 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
| IllustrationInfo | |
| Items | – Name: Title Label: Title Group: Ti Data: Synthesis and electronic structure determination of uranium(vi) ligand radical complexes. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Herasymchuk%2C+Khrystyna%22">Herasymchuk, Khrystyna</searchLink><relatesTo>1</relatesTo><br /><searchLink fieldCode="AR" term="%22Chiang%2C+Linus%22">Chiang, Linus</searchLink><relatesTo>1</relatesTo><br /><searchLink fieldCode="AR" term="%22Hayes%2C+Cassandra+E%2E%22">Hayes, Cassandra E.</searchLink><relatesTo>1</relatesTo><br /><searchLink fieldCode="AR" term="%22Brown%2C+Matthew+L%2E%22">Brown, Matthew L.</searchLink><relatesTo>1</relatesTo><br /><searchLink fieldCode="AR" term="%22Ovens%2C+Jeffrey+S%2E%22">Ovens, Jeffrey S.</searchLink><relatesTo>1</relatesTo><br /><searchLink fieldCode="AR" term="%22Patrick%2C+Brian+O%2E%22">Patrick, Brian O.</searchLink><relatesTo>2</relatesTo><br /><searchLink fieldCode="AR" term="%22Leznoff%2C+Daniel+B%2E%22">Leznoff, Daniel B.</searchLink><relatesTo>1</relatesTo><br /><searchLink fieldCode="AR" term="%22Storr%2C+Tim%22">Storr, Tim</searchLink><relatesTo>1</relatesTo> – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Dalton+Transactions%3A+An+International+Journal+of+Inorganic+Chemistry%22">Dalton Transactions: An International Journal of Inorganic Chemistry</searchLink>. 8/21/2016, Vol. 45 Issue 31, p12576-12586. 11p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Ligands+%28Chemistry%29%22">Ligands (Chemistry)</searchLink><br /><searchLink fieldCode="DE" term="%22Cations%22">Cations</searchLink><br /><searchLink fieldCode="DE" term="%22Amines%22">Amines</searchLink><br /><searchLink fieldCode="DE" term="%22Radicals+%28Chemistry%29%22">Radicals (Chemistry)</searchLink><br /><searchLink fieldCode="DE" term="%22Oxidation%22">Oxidation</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: Pentagonal bipyramidal uranyl (UO22+) complexes of salen ligands, N,N′-bis(3-tert-butyl-(5R)-salicylidene)-1,2-phenylenediamine, in which R = tBu (1a), OMe (1b), and NMe2 (1c), were prepared and the electronic structure of the one-electron oxidized species [1a–c]+ were investigated in solution. The solid-state structures of 1a and 1b were solved by X-ray crystallography, and in the case of 1b an asymmetric UO22+ unit was found due to an intermolecular hydrogen bonding interaction. Electrochemical investigation of 1a–c by cyclic voltammetry showed that each complex exhibited at least one quasi-reversible redox process assigned to the oxidation of the phenolate moieties to phenoxyl radicals. The trend in redox potentials matches the electron-donating ability of the para-phenolate substituents. The electron paramagnetic resonance spectra of cations [1a–c]+ exhibited gav values of 1.997, 1.999, and 1.995, respectively, reflecting the ligand radical character of the oxidized forms, and in addition, spin–orbit coupling to the uranium centre. Chemical oxidation as monitored by ultraviolet-visible-near-infrared (UV-vis-NIR) spectroscopy afforded the one-electron oxidized species. Weak low energy intra-ligand charge transfer (CT) transitions were observed for [1a–c]+ indicating localization of the ligand radical to form a phenolate/phenoxyl radical species. Further analysis using density functional theory (DFT) calculations predicted a localized phenoxyl radical for [1a–c]+ with a small but significant contribution of the phenylenediamine unit to the spin density. Time-dependent DFT (TD-DFT) calculations provided further insight into the nature of the low energy transitions, predicting both phenolate to phenoxyl intervalence charge transfer (IVCT) and phenylenediamine to phenoxyl CT character. Overall, [1a–c]+ are determined to be relatively localized ligand radical complexes, in which localization is enhanced as the electron donating ability of the para-phenolate substituents is increased (NMe2 ＞ OMe ＞ tBu). [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Dalton Transactions: An International Journal of Inorganic Chemistry is the property of Royal Society of Chemistry and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
| PLink | https://search.ebscohost.com/login.aspx?direct=true&site=eds-live&db=egs&AN=117156362 |
| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.1039/c6dt02089e Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 11 StartPage: 12576 Subjects: – SubjectFull: Ligands (Chemistry) Type: general – SubjectFull: Cations Type: general – SubjectFull: Amines Type: general – SubjectFull: Radicals (Chemistry) Type: general – SubjectFull: Oxidation Type: general Titles: – TitleFull: Synthesis and electronic structure determination of uranium(vi) ligand radical complexes. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Herasymchuk, Khrystyna – PersonEntity: Name: NameFull: Chiang, Linus – PersonEntity: Name: NameFull: Hayes, Cassandra E. – PersonEntity: Name: NameFull: Brown, Matthew L. – PersonEntity: Name: NameFull: Ovens, Jeffrey S. – PersonEntity: Name: NameFull: Patrick, Brian O. – PersonEntity: Name: NameFull: Leznoff, Daniel B. – PersonEntity: Name: NameFull: Storr, Tim IsPartOfRelationships: – BibEntity: Dates: – D: 21 M: 08 Text: 8/21/2016 Type: published Y: 2016 Identifiers: – Type: issn-print Value: 14779226 Numbering: – Type: volume Value: 45 – Type: issue Value: 31 Titles: – TitleFull: Dalton Transactions: An International Journal of Inorganic Chemistry Type: main |
| ResultId | 1 |
