NMR Studies on cis-trans Isomers of Rhodium 2-Thenoyltrifluoroacetonate

Abstract

Rhodium 2-thenoyltrifluoroacetonate Rh(tta)₃ was synthesized and ¹H NMR (60 MHz) and ¹⁹F NMR (56.4 MHz) studies on this were made in various solvents. In dimethyl sulfoxide, methyl isobutyl ketone and cyclohexanone, triplet and quartet were observed in ¹⁹F NMR spectra. These resonance lines were assigned by the peak area ratios and the investigation of the geometrical configuration of the isomers.
The relative content of isomers in the above three solvents could be determined by measuring the signal intensity ratios of CF, fluorines. The relative content of cis isomer was found to be less than 20 mold on-the synthesized sample. Equilibrium constants for isomerization of chelates in solvents were also evaluated at several temperatures ane the heats of isomerization were found to be roughly less than 5 kcal/mol.