(Dimethylamino)borylene and Related Complexes of Electron-Rich Metal Fragments: Generation of Nucleophile-Resistant Cations by Spontaneous Halide Ejection
Spontaneous halide ejection from a three-coordinate Lewis acid has been shown to offer a remarkable new route to cationic metal complexes featuring a linear, multiply bonded boron-donor ligand. The exploitation of electron-rich [CpM(PR 3) 2] fragments within boryl systems of the type L nMB(hal)NR 2...
| Váldodahkkit: | , , , , , , , , |
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| Materiálatiipa: | Journal article |
| Giella: | English |
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2012
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| _version_ | 1826300132168040448 |
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| author | Addy, D Phillips, N Pierce, G Vidovic, D Kraemer, T Mallick, D Jemmis, E Reid, G Aldridge, S |
| author_facet | Addy, D Phillips, N Pierce, G Vidovic, D Kraemer, T Mallick, D Jemmis, E Reid, G Aldridge, S |
| author_sort | Addy, D |
| collection | OXFORD |
| description | Spontaneous halide ejection from a three-coordinate Lewis acid has been shown to offer a remarkable new route to cationic metal complexes featuring a linear, multiply bonded boron-donor ligand. The exploitation of electron-rich [CpM(PR 3) 2] fragments within boryl systems of the type L nMB(hal)NR 2 leads to the spontaneous formation in polar solvents of chemically robust borylene complexes, [L nM(BNR 2)] +, with exceptionally low electrophilicity and short M-B bonds. This is reflected by M-B distances (ca. 1.80 Å for FeB systems) which are more akin to alkyl-/aryl-substituted borylene complexes and, perhaps most strikingly, by the very low exothermicity associated with the binding of pyridine to the two-coordinate boron center (ΔH = -7.4 kcal mol -1, cf. -40.7 kcal mol -1 for BCl 3). Despite the strong π electron release from the metal fragment implied by this suppressed reactivity and by such short M-B bonds, the barrier to rotation about the Fe=B bond in the unsymmetrical variant [CpFe(dmpe)(BN{C 6H 4OMe-4}Me)] + is found to be very small (ca. 2.9 kcal mol -1). This apparent contradiction is rationalized by the orthogonal orientations of the HOMO and HOMO-2 orbitals of the [CpML 2] + fragment, which mean that the M-B π interaction does not fall to zero even in the highest energy conformation. © 2012 American Chemical Society. |
| first_indexed | 2024-03-07T05:12:30Z |
| format | Journal article |
| id | oxford-uuid:dc0b6e92-b13d-42bd-a0de-e67d35cbafaf |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T05:12:30Z |
| publishDate | 2012 |
| record_format | dspace |
| spelling | oxford-uuid:dc0b6e92-b13d-42bd-a0de-e67d35cbafaf2022-03-27T09:15:05Z(Dimethylamino)borylene and Related Complexes of Electron-Rich Metal Fragments: Generation of Nucleophile-Resistant Cations by Spontaneous Halide EjectionJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:dc0b6e92-b13d-42bd-a0de-e67d35cbafafEnglishSymplectic Elements at Oxford2012Addy, DPhillips, NPierce, GVidovic, DKraemer, TMallick, DJemmis, EReid, GAldridge, SSpontaneous halide ejection from a three-coordinate Lewis acid has been shown to offer a remarkable new route to cationic metal complexes featuring a linear, multiply bonded boron-donor ligand. The exploitation of electron-rich [CpM(PR 3) 2] fragments within boryl systems of the type L nMB(hal)NR 2 leads to the spontaneous formation in polar solvents of chemically robust borylene complexes, [L nM(BNR 2)] +, with exceptionally low electrophilicity and short M-B bonds. This is reflected by M-B distances (ca. 1.80 Å for FeB systems) which are more akin to alkyl-/aryl-substituted borylene complexes and, perhaps most strikingly, by the very low exothermicity associated with the binding of pyridine to the two-coordinate boron center (ΔH = -7.4 kcal mol -1, cf. -40.7 kcal mol -1 for BCl 3). Despite the strong π electron release from the metal fragment implied by this suppressed reactivity and by such short M-B bonds, the barrier to rotation about the Fe=B bond in the unsymmetrical variant [CpFe(dmpe)(BN{C 6H 4OMe-4}Me)] + is found to be very small (ca. 2.9 kcal mol -1). This apparent contradiction is rationalized by the orthogonal orientations of the HOMO and HOMO-2 orbitals of the [CpML 2] + fragment, which mean that the M-B π interaction does not fall to zero even in the highest energy conformation. © 2012 American Chemical Society. |
| spellingShingle | Addy, D Phillips, N Pierce, G Vidovic, D Kraemer, T Mallick, D Jemmis, E Reid, G Aldridge, S (Dimethylamino)borylene and Related Complexes of Electron-Rich Metal Fragments: Generation of Nucleophile-Resistant Cations by Spontaneous Halide Ejection |
| title | (Dimethylamino)borylene and Related Complexes of Electron-Rich Metal Fragments: Generation of Nucleophile-Resistant Cations by Spontaneous Halide Ejection |
| title_full | (Dimethylamino)borylene and Related Complexes of Electron-Rich Metal Fragments: Generation of Nucleophile-Resistant Cations by Spontaneous Halide Ejection |
| title_fullStr | (Dimethylamino)borylene and Related Complexes of Electron-Rich Metal Fragments: Generation of Nucleophile-Resistant Cations by Spontaneous Halide Ejection |
| title_full_unstemmed | (Dimethylamino)borylene and Related Complexes of Electron-Rich Metal Fragments: Generation of Nucleophile-Resistant Cations by Spontaneous Halide Ejection |
| title_short | (Dimethylamino)borylene and Related Complexes of Electron-Rich Metal Fragments: Generation of Nucleophile-Resistant Cations by Spontaneous Halide Ejection |
| title_sort | dimethylamino borylene and related complexes of electron rich metal fragments generation of nucleophile resistant cations by spontaneous halide ejection |
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