Infrared and UV–visible absorption spectra of hexafluoroacetylacetone in a low-temperature argon matrix. I. Structure of a non-chelated enol-type isomer

Photoisomerization of hexafluoroacetylacetone was investigated by a low-temperature matrix-isolation technique with an aid of the density functional theory (DFT) calculation. A less stable isomer produced by UV irradiation (λ>260 nm) from the most stable enol was identified by its IR and UV–visible absorption spectra. This isomer was found to be non-chelated enol with cis, trans, and trans conformations around the CO–CH, CHC, and C–OH bonds, respectively, by a comparison with the spectral patterns of seven possible isomers with non-chelated enols derived from DFT simulations.