Smart omni transmission accessory

Detection of the signals corresponding to the characteristic chemical groups of the materials used to produce the polymeric scaffold was analyzed by attenuated total reflection Fourier transform infrared spectroscopy (ATR/FTIR), carried out with a Nicolet iS10 equipped with a Smart OMNI-Transmission accessory (Thermo Scientific, Waltham, MA, USA). The spectra were recorded with a resolution of 4 cm⁻¹ (64 scan) in the range of 4000–650 cm⁻¹. The Essential FTIR^® version 3.50.194 was used to further analyze the spectra.

Chalcone MB was synthesized and characterized by the Laboratory of Organic and Pharmaceutical Chemistry, Department of Chemical Sciences, Faculty of Pharmacy/CIIMAR research group, as previously described [27 (link)]. Methoxy PEG 2000, Methoxy PEG 5000, ε-caprolactone, and Sn(oct)₂ were acquired from Sigma-Aldrich Co. (Sintra, Portugal) and methanol (HPLC grade) from VWR chemicals. IR spectra were obtained in a KBr microplate in an FTIR spectrometer Nicolet iS 10 from Thermo Scientific with the Smart OMNI-Transmission accessory (Software OMNIC 8.3, Thermo Scientific, Madison, WI, USA). ¹H and ¹³C NMR spectra were recorded in the Department of Chemistry at the University of Aveiro, Portugal, on a Bruker Avance 300 instrument (Bruker Biosciences Corporation, Billerica, MA, USA) (¹H: 300.13 MHz; ¹³C: 75.47 MHz). ¹³C NMR assignments were made in bidimensional HSQC and HMBC experiments (long-range C, H coupling constants were optimized to 7 and 1 Hz). Chemical shifts are expressed in ppm values relative to tetramethylsilane (TMS) as an internal reference and coupling constants are reported in hertz (Hz). HPLC was performed on a Dionex Ultimate 3000 (Thermo Scientific, Darmstadt, Germany).