Comprehensive Vibrational Spectroscopy Analysis

Attenuated total reflectance Fourier-transform infrared (ATR FT-IR) spectroscopy was used to generate mid-IR (4000–400 cm⁻¹) and far-IR (700–100 cm⁻¹) spectra of the compounds. Mid-IR spectra were collected with a Bruker Alpha FT-IR spectrometer, which was equipped with a single-bounce diamond ATR crystal, a deuterated triglycine sulfate (DTGS) detector, and a SiC globar source. Far-IR spectra were measured with a Nicolet 6700 FT-IR spectrometer. This instrument is equipped with a deuterated lanthanum α alanine-doped triglycine sulfate (DLaTGS) detector covered with a polyethylene window and an EverGlo IR source. Samples for far-IR analysis were deposited onto a Harrick DiaMAX diamond ATR accessory. Mid- and far-IR spectra were collected at 1 cm⁻¹ resolution. FT–Raman spectroscopy was performed with a Thermo NXR 9610 Raman spectrometer. Each sample was transferred to a quartz NMR tube and sealed inside an argon-filled glove box. The samples were then measured in a 180° backscattering geometry with a 976 nm excitation laser set to 1.0 W. The spectral resolution was 4 cm⁻¹. All of the vibrational spectra were measured at room temperature and ambient pressure. Spectral deconvolution was performed with Fityk (version 1.3.1) [79 (link)].