Silica gel 60 f254 glass backed plates

Commercially available reagents were used without additional purification. E. Merck Kieselgel 60 was used for column chromatography. Thin layer chromatography (TLC) was performed on silica gel 60 F254 glass-backed plates (MERCK, Rahway, NJ, USA). Visualization was performed by UV light irradiation (254 or 312 nm) and staining with KMnO4. NMR spectra were recorded on a 700 MHz Bruker Avance III NMR at 303 K, 800 MHz Bruker Avance III NMR at 333 K and Bruker Fourier 300. Chemical shifts are reported relative to residue peaks of DMSO-d6 (2.51 ppm for ¹H and 39.5 ppm for ¹³C). Melting points were measured on an SMP 30 apparatus. High-resolution mass spectra (HRMS) were recorded on an LTQ Orbitrap Elite (ThermoScientific, Waltham, MA, USA) using electrospray ionization (ESI). The measurements were done in a positive ion mode (interface capillary voltage −5000 V) or in a negative ion mode (3500 V); the interface temperature was set at 275 °C.
All spectral data and other characteristics of the obtained compounds are presented in Supplementary Materials Parts 6 and 8. All solid chromophores were dissolved in DMSO (Sigma Aldrich, St. Louis, MO, USA. “for molecular biology” grade. #cat D8418) in 5 mM concentration and stored in a dark place at −20 °C for no more than 3 months.