FTIR data for S1, S3 and S4

For the FTIR analysis, sample preparation involved fine grinding of the sample and potassium bromide (KBr) to reduce the particle size. The sample and KBr powder were mixed in a 100:1 ratio by weight and ground in an agate mortar to achieve a homogeneous mixture. This mixture was placed in a pellet die and subjected to a hydraulic press at around 8 tons of pressure to form a transparent KBr pellet.

The FTIR spectrometer, equipped with an interferometer, beam splitter, and detector, was then used to analyze the sample. Infrared radiation was passed through the sample and the resulting spectrum was obtained by detecting the light that was not absorbed by the sample. This raw data, or interferogram, was processed using a Fourier transform to convert it into a usable spectrum. The final spectrum was analyzed to identify chemical bonds and molecular structures based on characteristic absorption peaks.