*2.2. Infrared Spectroscopy*

FTIR-ATR spectra were acquired by means of a Thermo Scientific Nicolet iS10 instrument, in the range between 4000 and 600 cm−1, 4 cm−<sup>1</sup> resolution, 32 scans. The background was periodically registered. Spectra were interpreted by comparison with a homemade reference database and with the literature.
