Chiral supramolecules: organometallic molecular loops made from enantiopure R-[cis-Rh2(C6H4PPh2)2(CH3CN)6](BF4)2.
Two enantiopure molecular loops, RR-[cis-Rh2(C6H4PPh2)2(py)2O2C(CF2)(n)CO2]2 (1, n = 2 and 2, n = 3) have been made from the reaction in CH2Cl2 and CH3OH of the inherently chiral dirhodium compound, R-[cis-Rh2(C6H4PPh2)2(CH3CN)6](BF4)2, and HO2C(CF2)(n)CO2H in the presence of an excess of pyridine. Single-crystal structure analyses reveal that each of these compounds is composed of two R-cis-Rh2(C6H4PPh2)2(ax-py)2(2+) units, and two equatorial perfluorodicarboxylate linkers, which form a loop oligomer. The 1H, 19F, and 31P[1H] NMR spectra in CDCl3 and C5D5N indicate that only one type of highly symmetric species exists in each solution, which is consistent with the solid-state structures.
Cotton
F Albert
FA
Department of Chemistry and Laboratory for Molecular Structure and Bonding, P.O. Box 3012, Texas A&M University, College Station, Texas 77842-3012, USA. cotton@tamu.edu
Murillo
Carlos A
CA
Yu
Rongmin
R