Controlling selectivity in the reductive activation of CO2 by mixed sandwich uranium(iii) complexes
The synthesis and molecular structures of a range of uranium(III) mixed sandwich complexes of the type [U(η8-C8H6(1,4-SiMe3)2)(η5-CpMe4R)] (R = Me, Et, iPr, tBu) and their reactivity towards CO2 are reported. The nature of the R group on the cyclopentadienyl ring in the former has a significant effe...
| Main Authors: | , , , , |
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| Format: | Journal article |
| Language: | English |
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Royal Society of Chemistry
2014
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| _version_ | 1824458558799872000 |
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| author | Tsoureas, N Castro, L Kilpatrick, A Cloke, FGN Maron, L |
| author_facet | Tsoureas, N Castro, L Kilpatrick, A Cloke, FGN Maron, L |
| author_sort | Tsoureas, N |
| collection | OXFORD |
| description | The synthesis and molecular structures of a range of uranium(III) mixed sandwich complexes of the type [U(η8-C8H6(1,4-SiMe3)2)(η5-CpMe4R)] (R = Me, Et, iPr, tBu) and their reactivity towards CO2 are reported. The nature of the R group on the cyclopentadienyl ring in the former has a significant effect on the outcome of CO2 activation: when R = Me, the products are the bridging oxo complex {U[η8-C8H6(1,4-SiMe3)2](η5-CpMe5)}2(μ-O) and the bridging oxalate complex {U[η8-C8H6(1,4-SiMe3)2](η5-CpMe5)}2(μ-η2:η2-C2O4); for R = Et or iPr, bridging carbonate {U[η8-C8H6(1,4-SiMe3)2](η5-CpMe4R)}2(μ-η1:η2-CO3) and bridging oxalate complexes {U[η8-C8H6(1,4-SiMe3)2](η5-CpMe4R)}2(μ-η2:η2-C2O4) are formed in both cases; and when R = tBu the sole product is the bridging carbonate complex {U[η8-C8H6(1,4-SiMe3)2](η5-CpMe4tBu)}2(μ-η1:η2-CO3). Electrochemical studies on both the uranium(III) complexes and the dimeric uranium(IV) CO2 reduction products have been carried out and all exhibit quasi reversible redox processes; in particular, the similarities in the U(III)/U(IV) redox couples suggest that the selectivity in the outcome of CO2 reductive activation by these complexes is steric in origin rather than electronic. The latter conclusion is supported by a detailed computational DFT study on the potential mechanistic pathways for reduction of CO2 by this system. |
| first_indexed | 2025-02-19T04:27:48Z |
| format | Journal article |
| id | oxford-uuid:150392d3-9f38-4ec9-a6ee-84080d9fbf44 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2025-02-19T04:27:48Z |
| publishDate | 2014 |
| publisher | Royal Society of Chemistry |
| record_format | dspace |
| spelling | oxford-uuid:150392d3-9f38-4ec9-a6ee-84080d9fbf442024-12-12T12:28:52ZControlling selectivity in the reductive activation of CO2 by mixed sandwich uranium(iii) complexesJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:150392d3-9f38-4ec9-a6ee-84080d9fbf44EnglishSymplectic Elements at OxfordRoyal Society of Chemistry2014Tsoureas, NCastro, LKilpatrick, ACloke, FGNMaron, LThe synthesis and molecular structures of a range of uranium(III) mixed sandwich complexes of the type [U(η8-C8H6(1,4-SiMe3)2)(η5-CpMe4R)] (R = Me, Et, iPr, tBu) and their reactivity towards CO2 are reported. The nature of the R group on the cyclopentadienyl ring in the former has a significant effect on the outcome of CO2 activation: when R = Me, the products are the bridging oxo complex {U[η8-C8H6(1,4-SiMe3)2](η5-CpMe5)}2(μ-O) and the bridging oxalate complex {U[η8-C8H6(1,4-SiMe3)2](η5-CpMe5)}2(μ-η2:η2-C2O4); for R = Et or iPr, bridging carbonate {U[η8-C8H6(1,4-SiMe3)2](η5-CpMe4R)}2(μ-η1:η2-CO3) and bridging oxalate complexes {U[η8-C8H6(1,4-SiMe3)2](η5-CpMe4R)}2(μ-η2:η2-C2O4) are formed in both cases; and when R = tBu the sole product is the bridging carbonate complex {U[η8-C8H6(1,4-SiMe3)2](η5-CpMe4tBu)}2(μ-η1:η2-CO3). Electrochemical studies on both the uranium(III) complexes and the dimeric uranium(IV) CO2 reduction products have been carried out and all exhibit quasi reversible redox processes; in particular, the similarities in the U(III)/U(IV) redox couples suggest that the selectivity in the outcome of CO2 reductive activation by these complexes is steric in origin rather than electronic. The latter conclusion is supported by a detailed computational DFT study on the potential mechanistic pathways for reduction of CO2 by this system. |
| spellingShingle | Tsoureas, N Castro, L Kilpatrick, A Cloke, FGN Maron, L Controlling selectivity in the reductive activation of CO2 by mixed sandwich uranium(iii) complexes |
| title | Controlling selectivity in the reductive activation of CO2 by mixed sandwich uranium(iii) complexes |
| title_full | Controlling selectivity in the reductive activation of CO2 by mixed sandwich uranium(iii) complexes |
| title_fullStr | Controlling selectivity in the reductive activation of CO2 by mixed sandwich uranium(iii) complexes |
| title_full_unstemmed | Controlling selectivity in the reductive activation of CO2 by mixed sandwich uranium(iii) complexes |
| title_short | Controlling selectivity in the reductive activation of CO2 by mixed sandwich uranium(iii) complexes |
| title_sort | controlling selectivity in the reductive activation of co2 by mixed sandwich uranium iii complexes |
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