*2.5. Fourier Transform Infrared Spectroscopy (FT-IR)*

The infrared spectra of all samples were measured using FT-IR (FT-IR- 4200 spectrometer, JASCO Co., Tokyo, Japan) with an attenuated total reflection (ATR) unit (ATR-PRO 670H-S, JASCO Co., Tokyo, Japan). The recorded spectrum represents an average of 64 scans obtained with a resolution of 4 cm−<sup>1</sup> at room temperature. The spectra were collected in wavenumbers ranging from 4000 to 400 cm−<sup>1</sup> . The internal reflectance element used in this study was a diamond trapezoid having 45◦ entrance and exit faces.
