| Autor: |
Kogut E; Department of Chemistry, Georgetown University, Box 571227, Washington, DC 20057-1227, USA., Wiencko HL, Zhang L, Cordeau DE, Warren TH |
| Jazyk: |
angličtina |
| Zdroj: |
Journal of the American Chemical Society [J Am Chem Soc] 2005 Aug 17; Vol. 127 (32), pp. 11248-9. |
| DOI: |
10.1021/ja0533186 |
| Abstrakt: |
The synthesis and structure of the beta-diketiminato Ni(I) lutidine adducts [MexNN]Ni(2,4-lutidine) (x = 2 (2); x = 3 (3)) are described which serve as synthons to the "naked" 13-electron [MexNN]Ni fragments in reactions with N3Ad to give Ni-imido complexes. The singly bridged imide {[Me2NN]Ni}2(mu-NAd) (4) possesses short Ni-Ni (2.506(1) A) and Ni-N(imido) distances (1.732(4)-1.752(4) A). Steric modification of the beta-diketiminate ligand to include an additional methyl group in the N-aryl 4-position affords the Ni(III) terminal imide [Me3NN]Ni=NAd (8) isolated in 52% yield. The X-ray structure of terminal imide 8 reveals a contracted Ni-N(imido) bond distance (1.662(2) A) and an only somewhat bent imido linkage (Ni-N-C = 164.5(2) degrees ) consistent with a significant degree of multiple bond character. Frozen glass EPR studies of 5 indicate a rhombic environment in which one of the signals exhibits strong hyperfine coupling (A = 22 G) to the imido 14N (I = 1) nucleus. The terminal imide 5 undergoes complete imido group transfer to CO and CNBut to give AdNCO and AdNCNBut, respectively, as well as with PMe3 to afford AdN=PMe3. Exemplifying the radical character at the imido N atom, 5 adds to cobaltocene and abstracts a H atom from 1,4-cyclohexadiene to give the Ni(II)-amides [Me3NN]Ni-NAd(eta4-C5H5)CoCp (7) and [Me3NN]Ni-NHAd (8). |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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