Brunner, Henri and Faustmann, Peter and Dietl, Andreas and Nuber, Bernhard (1997) Optically active transition metal compounds .112. Synthesis of chiral carbonylnitrosylcobalt complexes with bidentate PP*, PN* and NN* ligands. JOURNAL OF ORGANOMETALLIC CHEMISTRY, 542 (2). pp. 255-263. ISSN 0022-328X, 1872-8561
Full text not available from this repository.Abstract
The substitution of two carbonyl groups in Co(CO)(3)(NO) by optically active unsymmetrical bidentate ligands LL* yields pairs of diastereomers Co(CO)(NO)(LL*), which differ only in the configuration at the Co atom. LL* can be a bisphosphane, trisphosphane, phosphaneimine or pyridineimine. For the complexes 2 (LL* = (S,S)-norphos), 3 (LL* = (R)-1,2,4-triphos) and 4 (LL* = (R)-1,2,5-triphos) the diastereomer ratios of 45:55 (2a:2b), 83:17 (3a:3b) and 63:37 (4a:4b) respectively indicate an optical induction from the Ligand to the metal configuration during the synthesis. By crystallization it is possible to separate the diastereomers of 1 (LL* = (R)-prophos), 2 and 3. 1a and 3a are obtained as pure diastereomers, 2a as an enriched sample (2a:2b 73:27). The crystal structures and absolute configurations of (S-Co,R-C)-1a and (S-Co,R-C)-3a were determined by X-ray analysis. In 3a the cobalt center is configurationally stable at room temperature, whereas 1a epimerizes in benzene-d(6) at 35 degrees C with a half-life of tau(1/2) = 141 min and 2a in CDCl3 at 24 degrees C with tau(1/2) = 160 min. (C) 1997 Elsevier Science S.A.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | ASYMMETRIC CATALYZES; RH-COMPLEXES; HYDROGENATION; ACID; HYDROSILYLATION; OLEFINS; NORPHOS; chirality; cobalt(carbonyl)(nitrosyl) complexes; X-ray structure analysis |
| Subjects: | 500 Science > 540 Chemistry & allied sciences |
| Divisions: | Chemistry and Pharmacy > Institut für Anorganische Chemie > Alumni or Retired Professors > Prof. Dr. Henri Brunner |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 29 Mar 2023 08:54 |
| Last Modified: | 29 Mar 2023 08:54 |
| URI: | https://pred.uni-regensburg.de/id/eprint/50553 |
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