Brunner, Henri and Oeschey, Ralf and Nuber, Bernd (1996) Optically active transition metal complexes .109. Novel (eta(6)-benzene)ruthenium complexes with a chiral pyrrolecarbaldiminato chelate ligand: Synthesis, crystal structures, properties, and stereochemistry at the ruthenium atom. ORGANOMETALLICS, 15 (16). pp. 3616-3624. ISSN 0276-7333, 1520-6041
Full text not available from this repository.Abstract
The reaction of [(eta(6)-C6H6)RuCl2](2) with the sodium salt of (+)-(S)-N-(1-phenylethyl)-pyrrolecarbaldimine (HLL*) in CH2Cl2 yielded a mixture of the two diastereomers (S-Ru,S-C)- and (R(Ru),S-C)-[(eta 6-C6H6)Ru(LL*)Cl] (1a,b) in a ratio of 68:32. The chloride ligand in 1a,b was replaced in methanol by triphenylphosphane to give the two diastereomers (S-Ru,S-C)- and (R(Ru),S-C)-[(eta(6)-C6H6)Ru(LL*)(PPh(3))]PF6 (2a,b). According to variable-temperature H-1 NMR studies the formation of configurationally labile solvate intermediates has to be assumed in the reaction of the chloro complexes 1a,b with triphenylphosphane in the solvent methanol. In contrast to the diastereomers 1a,b, the ruthenium configuration in the phosphane complexes 2a,b is configurationally stable at room temperature. The diastereomers 2a,b were separated by crystallization. The crystal structures of (S-Ru,S-C)-1a, (S-Ru,S-C)-2a, and (R(Ru),S-C)-2b were determined by X-ray analysis. The epimerization of 2b at 85 degrees C in nitromethane-d(3) gave a 93.5:6.5 equilibrium mixture of 2a and 2b (tau(1/2) (min) = 58.2 +/- 0.4). Conformational analyses showed that two main factors govern the orientation of the 1-phenylethyl group relative to the [(eta(6)-C6H6)Ru(LL*)X] moiety (X = Cl, PPh(3)): (i) the face-on orientation of the phenyl substituent with respect to the pi-bonded benzene ligand and (ii) the orientation of the hydrogen substituent toward the unidentate ligand L.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | SCHIFF-BASE COMPLEXES; PI-PI-INTERACTIONS; X-RAY STRUCTURE; ASYMMETRIC HYDROGENATION; CONFORMATIONAL-ANALYSIS; CONFIGURATION; P(O-TOLYL)3; SYSTEMATICS; PHOSPHORUS; CATALYSTS |
| 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 Jun 2023 08:06 |
| Last Modified: | 29 Jun 2023 08:06 |
| URI: | https://pred.uni-regensburg.de/id/eprint/51548 |
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