Identification of geometrical isomers using vibrational circular dichroism spectroscopy: A series of mixed-ligand complexes of diamagnetic Co(III) ions

Vibrational circular dichroism (VCD) spectra were measured on the chloroform solutions of a series of mixed-ligand diamagnetic Co(iii) complexes, [Co(tfac)_n(acac)_3-n] (n = 0-3, tfac = 1,1,1-trifluoro-2,4- pentanedionato; acac = acetylacetonato). Distinct differences were observed in the VCD spectra among the geometrical isomers of the same ligand composition. Such differentiation was hardly possible by their infra-red spectra alone. The structural identification of these isomers was performed in conjunction with DFT calculations.