Zusammenfassung
Treatment of the chiral tripod ligand (L-Ment,S-C)-CpH(PNMent) with (Ph3P)(3)RuCl2 in ethanol afforded the two chiral-at-metal diastereomers (L-Ment,S-C,R-Ru)- and (L-Ment,S-C,S-Ru)-[Cp(PNMent)Ru(PPh3)Cl] (70% de) in which the cyclopentadienyl group and the P atom of the ligand coordinated at the metal center. The (L-Ment,S-C,R-Ru)-diastereomer was isolated by crystallization from ethanol-pentane ...
Zusammenfassung
Treatment of the chiral tripod ligand (L-Ment,S-C)-CpH(PNMent) with (Ph3P)(3)RuCl2 in ethanol afforded the two chiral-at-metal diastereomers (L-Ment,S-C,R-Ru)- and (L-Ment,S-C,S-Ru)-[Cp(PNMent)Ru(PPh3)Cl] (70% de) in which the cyclopentadienyl group and the P atom of the ligand coordinated at the metal center. The (L-Ment,S-C,R-Ru)-diastereomer was isolated by crystallization from ethanol-pentane and its structure was established by X-ray crystallography. The (L-Ment,S-C,R-Ru)-diastereomer epimerized in CDCl3 solution at 60 degrees C in a first-order reaction with a half-life of 5.66 h. In alcoholic solution epimerization occurred at room temperature. Substitution of the chloride ligand in (L-Ment,S-C,R-Ru)- and (L-Ment,S-C,S-Ru)-[Cp(PNMent)Ru(PPh3)Cl] by nitriles NCR (R = Me, Ph, CH2Ph) in the presence of NH4PF6 gave mixtures of the diastereomers (L-Ment,S-C,R-Ru)- and (L-Ment,S-C,S-Ru)-[Cp(PNMent)Ru(PPh3)NCR]PF6. Treatment of (L-Ment,S-C,R-Ru)- and (L-Ment,S-C,S-Ru)-[Cp(PNMent)Ru(PPh3)Cl] with piperidine or morpholine in the presence of NH4PF6 led to the chiral-at-metal diastereomers (L-Ment,S-C,R-Ru)- and (L-Ment,S-C,S-Ru)-[Cp(PNMent)Ru(PPh3)NH3]PF6 (6% de). (c) 2006 Elsevier B.V. All rights reserved.
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