Alkyl dehydrogenation in iridium tri-cyclopentyl phosphines
The iridium cyclooctadiene complex incorporating a tricyclopentyl phosphine ligand (PCyp3), Ir(η2:η2-C8H12)(PCyp3)Cl, has been prepared. Removal of the chloride from this complex using Na [BArF4] [ArF = C6 H3 (CF3)2] in CH2Cl2/arene solvent results in dehydrogenation (C-H activation followed by β-H...
| Main Authors: | , , , , , |
|---|---|
| Format: | Journal article |
| Language: | English |
| Published: |
2010
|
| _version_ | 1826291385144180736 |
|---|---|
| author | Moret, S Dallanegra, R Chaplin, AB Douglas, T Hiney, R Weller, A |
| author_facet | Moret, S Dallanegra, R Chaplin, AB Douglas, T Hiney, R Weller, A |
| author_sort | Moret, S |
| collection | OXFORD |
| description | The iridium cyclooctadiene complex incorporating a tricyclopentyl phosphine ligand (PCyp3), Ir(η2:η2-C8H12)(PCyp3)Cl, has been prepared. Removal of the chloride from this complex using Na [BArF4] [ArF = C6 H3 (CF3)2] in CH2Cl2/arene solvent results in dehydrogenation (C-H activation followed by β-H transfer) of one of the alkyl phosphine rings and formation of the complexes [Ir (η6 - C6 H5 X) {PCyp2 (η2 - C5 H7)}] [BArF4] (X = H, F) which contain a hybrid phosphine-alkene ligand. These complexes are formed alongside another product (5-20% yield) that has been identified as [Ir (η2 : η2 - C8 H12) {PCyp2 (η2 - C5 H7)}] [BArF4], which can be prepared in high yield by an alternative, and slightly modified, route. This complex is with a minor isomer that has been tentatively identified as [Ir (η2 : η3 - C8 H11) (H) {PCyp2 (η2 - C5 H7)}] [BArF4], which results from allylic C-H activation of cyclooctadiene. Addition of H2 to [Ir (η2 : η2 - C8 H12) {PCyp2 (η2 - C5 H7)}] [BArF4] and its isomer in arene solvent (C6H5X, X = F, H) forms the dihydrido η6-arene Ir(III) complexes [Ir (H)2 (η6 - C6 H5 X) (PCyp3)] [BArF4]. In contrast, hydrogenation in CH2Cl2 alone results in the formation of Ir (H)2 (PCyp3) {η6 - (C6 H3 (CF3)2) BArF3} in which the [BArF4]- anion is now acting as a ligand through one of its aryl rings. The fluorobenzene complex [Ir (H)2 (η6 - C6 H5 F) (PCyp3)] [BArF4] can be cleanly converted to [Ir (η6 - C6 H5 F) {PCyp2 (η2 - C5 H7)}] [BArF4] by addition of the hydrogen acceptor tert-butylethene (tbe). © 2009 Elsevier B.V. All rights reserved. |
| first_indexed | 2024-03-07T02:58:36Z |
| format | Journal article |
| id | oxford-uuid:b02a5a7d-8b62-4d9e-b925-a699056499ca |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T02:58:36Z |
| publishDate | 2010 |
| record_format | dspace |
| spelling | oxford-uuid:b02a5a7d-8b62-4d9e-b925-a699056499ca2022-03-27T03:54:31ZAlkyl dehydrogenation in iridium tri-cyclopentyl phosphinesJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:b02a5a7d-8b62-4d9e-b925-a699056499caEnglishSymplectic Elements at Oxford2010Moret, SDallanegra, RChaplin, ABDouglas, THiney, RWeller, AThe iridium cyclooctadiene complex incorporating a tricyclopentyl phosphine ligand (PCyp3), Ir(η2:η2-C8H12)(PCyp3)Cl, has been prepared. Removal of the chloride from this complex using Na [BArF4] [ArF = C6 H3 (CF3)2] in CH2Cl2/arene solvent results in dehydrogenation (C-H activation followed by β-H transfer) of one of the alkyl phosphine rings and formation of the complexes [Ir (η6 - C6 H5 X) {PCyp2 (η2 - C5 H7)}] [BArF4] (X = H, F) which contain a hybrid phosphine-alkene ligand. These complexes are formed alongside another product (5-20% yield) that has been identified as [Ir (η2 : η2 - C8 H12) {PCyp2 (η2 - C5 H7)}] [BArF4], which can be prepared in high yield by an alternative, and slightly modified, route. This complex is with a minor isomer that has been tentatively identified as [Ir (η2 : η3 - C8 H11) (H) {PCyp2 (η2 - C5 H7)}] [BArF4], which results from allylic C-H activation of cyclooctadiene. Addition of H2 to [Ir (η2 : η2 - C8 H12) {PCyp2 (η2 - C5 H7)}] [BArF4] and its isomer in arene solvent (C6H5X, X = F, H) forms the dihydrido η6-arene Ir(III) complexes [Ir (H)2 (η6 - C6 H5 X) (PCyp3)] [BArF4]. In contrast, hydrogenation in CH2Cl2 alone results in the formation of Ir (H)2 (PCyp3) {η6 - (C6 H3 (CF3)2) BArF3} in which the [BArF4]- anion is now acting as a ligand through one of its aryl rings. The fluorobenzene complex [Ir (H)2 (η6 - C6 H5 F) (PCyp3)] [BArF4] can be cleanly converted to [Ir (η6 - C6 H5 F) {PCyp2 (η2 - C5 H7)}] [BArF4] by addition of the hydrogen acceptor tert-butylethene (tbe). © 2009 Elsevier B.V. All rights reserved. |
| spellingShingle | Moret, S Dallanegra, R Chaplin, AB Douglas, T Hiney, R Weller, A Alkyl dehydrogenation in iridium tri-cyclopentyl phosphines |
| title | Alkyl dehydrogenation in iridium tri-cyclopentyl phosphines |
| title_full | Alkyl dehydrogenation in iridium tri-cyclopentyl phosphines |
| title_fullStr | Alkyl dehydrogenation in iridium tri-cyclopentyl phosphines |
| title_full_unstemmed | Alkyl dehydrogenation in iridium tri-cyclopentyl phosphines |
| title_short | Alkyl dehydrogenation in iridium tri-cyclopentyl phosphines |
| title_sort | alkyl dehydrogenation in iridium tri cyclopentyl phosphines |
| work_keys_str_mv | AT morets alkyldehydrogenationiniridiumtricyclopentylphosphines AT dallanegrar alkyldehydrogenationiniridiumtricyclopentylphosphines AT chaplinab alkyldehydrogenationiniridiumtricyclopentylphosphines AT douglast alkyldehydrogenationiniridiumtricyclopentylphosphines AT hineyr alkyldehydrogenationiniridiumtricyclopentylphosphines AT wellera alkyldehydrogenationiniridiumtricyclopentylphosphines |