*2.8. Infrared Spectroscopy*

Fourier-transform infrared (FT–IR) spectroscopic measurements were performed on a Bruker Tensor 27 FT–IR instrument (Bruker Corporation, Billerica, MA, USA) equipped with a single-reflection diamond crystal platinum ATR unit and OPUS data collection program. The scanning range was from 4000 to 400 cm−<sup>1</sup> with a resolution of 4 cm<sup>−</sup>1.
