Structural and spectroscopic characterization of fluorinated dioxole based salts: a combined experimental and computational study

The supramolecular solid state structure of Na+, K+, Ca2+ and salts of difluoro((2,2,4,5-tetrafluoro-5-(trifluoromethoxy)-1.3-dioxolan-4-yl)oxy)acetic acid have been investigated by means of IR and Raman vibrational spectroscopy, and Density Functional Theory (DFT) calculations on suitable molecular models. In the case of salts, additional insights have been provided by X-Ray diffraction measurements on crystalline powders. Based on the analysis of IR and Raman spectra, the structure of the different salts at the molecular level is identified. In salts, the spectra indicate the existence of different stable complexes, while for the other salts only one type of aggregation is observed. For salts, it has been analyzed the effect of solvation in water, focusing on the specific features shown by the IR spectrum: this gave a further insight on the peculiar aggregation properties observed. For all the cases studied, DFT calculations gave a satisfactory interpretation of the experimental vibrational spectra based on the structure of different models of molecular complexes, and allowed the identification of characteristic marker bands related to different supra-molecular architectures.