Cary 660 series ftir spectrometer

The chemical functionalities of the coating were identified using Fourier-transform infrared spectroscopy in attenuated total reflection mode (FTIR-ATR). Spectra were recorded on a Cary 660 Series FTIR spectrometer with a resolution of 4 cm⁻¹ (Agilent, Mulgrave, Australia), accumulating 128 scans between 4000 cm⁻¹ and 400 cm⁻¹. A Harrick SplitPea™ (Pleasantville, NY, USA) was configured to ensure contact between the sample and the silicon-based ATR crystal. For each sample, measurements were taken at four different points on the coating. These values were used to calculate the standard deviation of the average area under the peaks corresponding to chemical moieties of interest for the growth mode study.
Peak curve fitting in the region between 1500 and 1800 cm⁻¹ was performed using OriginPro software version 2021 via a Voigt-shaped curve-fitting method. This region exhibits features corresponding to two C=O bonds involved in different chemical moieties, namely, amide (N–RC=O) and ketone (R₂C=O). This fitting method suggests using an additional band at 1620 cm⁻¹ to fit the curve of this region. According to the literature, this band can be assigned to amine groups (N–H) in the deposited films, as derivatization experiments with chlorobenzaldehyde [37 (link)] (not shown) resulted in the disappearance of this feature [38 (link)].

Optical rotations were measured on a Rudolph Research Analytical Autopol I automatic polarimeter. Ultraviolet (UV) and CD spectra were recorded on a Jasco J-1500 Circular Dichroism Spectrometer. IR spectra were carried on an Agilent Cary 660 series FT-IR spectrometer (KBr). HRESIMS spectra were obtained on an Agilent 6230 HRESIMS spectrometer. 1D and 2D NMR spectra were performed on a Bruker Ascend 600 NMR spectrometer. The chemical shifts were expressed in δ (ppm) with TMS as an internal reference. Column chromatography was performed on Silica gel (40–60 mesh, Grace, USA) column. Thin layer chromatography was carried on precoated silica gel 60 F₂₅₄ plates (200 μm thick, Merck KGaA, Germany). MPLC was performed using a Buchi Sepacore flash system with a RP-18 column (SilicBond C₁₈, 36 × 460 mm ID, 40–63 μm particle size). Semi-preparative HPLC was conducted on an Agilent 1100/1200 liquid chromatography instrument with a Waters Xbridge Prep C₁₈ column (10 × 250 mm, 5 μm) or Xbridge Prep C₈ column (10 × 250 mm, 5 μm). UHPLC analyses were conducted on an Agilent 1290 system using a ZORBAX RRHD Eclipse Plus C₁₈ column (1.8 μm, 2.1 × 50 mm, Agilent).