Redox noninnocence in coordinated 2-(arylazo)pyridines: steric control of ligand-based redox processes in cobalt complexes.
A series of cobalt complexes of ligands based on the 2-(arylazo)pyridine architecture have been synthesized, and the precise structure and stoichiometry of the complexes depend critically on the identity of substituents in the 2, 4, and 6 positions of the phenyl ring. The 2-(arylazo)pyridine motif c...
| Autori principali: | , , , , , , |
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| Natura: | Journal article |
| Lingua: | English |
| Pubblicazione: |
2013
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| _version_ | 1826281752607326208 |
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| author | Ghosh, P Samanta, S Roy, S Joy, S Krämer, T McGrady, J Goswami, S |
| author_facet | Ghosh, P Samanta, S Roy, S Joy, S Krämer, T McGrady, J Goswami, S |
| author_sort | Ghosh, P |
| collection | OXFORD |
| description | A series of cobalt complexes of ligands based on the 2-(arylazo)pyridine architecture have been synthesized, and the precise structure and stoichiometry of the complexes depend critically on the identity of substituents in the 2, 4, and 6 positions of the phenyl ring. The 2-(arylazo)pyridine motif can support either Co(II) complexes with neutral ligands, Co(II)Cl2(L(a))2 (1), Co(II)Cl2(L(c))2 (3), [Co(II)Cl(L(b))2]2(PF6)2 (5[PF6]2), or Co(III) complexes of reduced 2-(arylazo)pyridine ligand radical anions, L(•-), Co(III)Cl(L(b•-))2 (2), Co(III)Cl(L(c•-))2 (4), and Co(III)Me(L(b•-))2 (6). All three members of the latter class are based on approximately trigonal-bipyramidal CoX(L(•-))2 architectures [L = 2-(arylazo)pyridine] with two azo nitrogen atoms and the X ligand (X = Cl or Me) in the equatorial plane and two pyridine nitrogen atoms occupying axial positions. Density functional theory suggests that the electronic structure of the Co(III) complexes is also dependent on the identity of X: the strong σ-donor methyl gives a low-spin (S = 0) configuration, while the σ/π-donor chloro gives an intermediate-spin (S = 1) local configuration. In certain cases, one-electron reduction of the Co(II)X2L2 complex leads to the formation of Co(III)X(L(•-))2; i.e., reduction of one ligand induces a further one-electron oxidation of the metal center with concomitant reduction of the second ligand. |
| first_indexed | 2024-03-07T00:33:32Z |
| format | Journal article |
| id | oxford-uuid:80a2ea59-f19b-4f04-8b89-f1597ea2d423 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T00:33:32Z |
| publishDate | 2013 |
| record_format | dspace |
| spelling | oxford-uuid:80a2ea59-f19b-4f04-8b89-f1597ea2d4232022-03-26T21:24:37ZRedox noninnocence in coordinated 2-(arylazo)pyridines: steric control of ligand-based redox processes in cobalt complexes.Journal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:80a2ea59-f19b-4f04-8b89-f1597ea2d423EnglishSymplectic Elements at Oxford2013Ghosh, PSamanta, SRoy, SJoy, SKrämer, TMcGrady, JGoswami, SA series of cobalt complexes of ligands based on the 2-(arylazo)pyridine architecture have been synthesized, and the precise structure and stoichiometry of the complexes depend critically on the identity of substituents in the 2, 4, and 6 positions of the phenyl ring. The 2-(arylazo)pyridine motif can support either Co(II) complexes with neutral ligands, Co(II)Cl2(L(a))2 (1), Co(II)Cl2(L(c))2 (3), [Co(II)Cl(L(b))2]2(PF6)2 (5[PF6]2), or Co(III) complexes of reduced 2-(arylazo)pyridine ligand radical anions, L(•-), Co(III)Cl(L(b•-))2 (2), Co(III)Cl(L(c•-))2 (4), and Co(III)Me(L(b•-))2 (6). All three members of the latter class are based on approximately trigonal-bipyramidal CoX(L(•-))2 architectures [L = 2-(arylazo)pyridine] with two azo nitrogen atoms and the X ligand (X = Cl or Me) in the equatorial plane and two pyridine nitrogen atoms occupying axial positions. Density functional theory suggests that the electronic structure of the Co(III) complexes is also dependent on the identity of X: the strong σ-donor methyl gives a low-spin (S = 0) configuration, while the σ/π-donor chloro gives an intermediate-spin (S = 1) local configuration. In certain cases, one-electron reduction of the Co(II)X2L2 complex leads to the formation of Co(III)X(L(•-))2; i.e., reduction of one ligand induces a further one-electron oxidation of the metal center with concomitant reduction of the second ligand. |
| spellingShingle | Ghosh, P Samanta, S Roy, S Joy, S Krämer, T McGrady, J Goswami, S Redox noninnocence in coordinated 2-(arylazo)pyridines: steric control of ligand-based redox processes in cobalt complexes. |
| title | Redox noninnocence in coordinated 2-(arylazo)pyridines: steric control of ligand-based redox processes in cobalt complexes. |
| title_full | Redox noninnocence in coordinated 2-(arylazo)pyridines: steric control of ligand-based redox processes in cobalt complexes. |
| title_fullStr | Redox noninnocence in coordinated 2-(arylazo)pyridines: steric control of ligand-based redox processes in cobalt complexes. |
| title_full_unstemmed | Redox noninnocence in coordinated 2-(arylazo)pyridines: steric control of ligand-based redox processes in cobalt complexes. |
| title_short | Redox noninnocence in coordinated 2-(arylazo)pyridines: steric control of ligand-based redox processes in cobalt complexes. |
| title_sort | redox noninnocence in coordinated 2 arylazo pyridines steric control of ligand based redox processes in cobalt complexes |
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