Tlc silica 60 f254

Electrospray ionization (ESI) mass spectra were recorded on a 1200-series HPLC-system or a 1260-series Infinity II HPLC-system (Agilent-Technologies, Santa Clara, CA, USA) with binary pump and integrated diode array detector coupled to an LC/MSD-Trap-XTC-mass spectrometer (Agilent-Technologies) or an LC/MSD Infinity lab LC/MSD (G6125B LC/MSD). High resolution mass spectra were recorded on a Micromass-Q-TOF-Ultima-3-mass spectrometer (Waters, Milford, MA, USA) with LockSpray-interface and a suitable external calibrant. Infrared (IR) spectra were recorded on a FTIR-spectrometer (Bruker Tensor 27, Billerica, MA, USA) equipped with a diamond ATR unit and are reported in terms of frequency of absorption in cm⁻¹. NMR spectra were recorded on a Bruker Avance III 500 HD (¹H: 500 MHz, ¹³C: 125 MHz) or Avance 600 (¹H-NMR: 600 MHz and ¹³C-NMR: 151.1 MHz). Chemical shifts δ (ppm) are reported relative to residual solvent signal. 2D spectra (COSY, HMQC, HMBC) and DEPT-135 spectra were used for signal assignment. Chromatographic purification of compounds was performed on silica gel (35–70 μm, Acros Organics, Fair Lawn, NJ, USA) and Sephadex LH-20. Thin-layer chromatography (TLC) was carried out on silica plates (TLC Silica 60 F₂₅₄ by Merck, Kenilworth, NJ, USA) and spots were detected by spraying with 20% H₂SO₄ followed by charring at 100 °C.

All chemicals were purchased from commercial suppliers, unless otherwise stated. The solvents were purified according to conventional methods [26 ]. Chromatographic purifications were performed with Macherey-Nagel, Silica 60, 0.063–0.2 mm. Merck aluminum plates (TLC Silica 60 F254, Darmstadt, Germany) were used for the TLC analysis, which was performed with dichloromethane/hexane mixtures as eluents.
¹H-NMR spectra of 10^–4 M solutions in CDCl₃ were recorded on a Bruker Avance III spectrometer (Billerica, MA, USA) at a frequency of 600 MHz at 303 K, using the resonance of the residual CHCl₃ as an internal reference (δ = 7.26 ppm). MALDI-TOF mass spectra were recorded on a Bruker Daltonics Ultraflex spectrometer (Billerica, MA, USA) in the positive ion mode without a matrix. UV–vis spectra were recorded on a Thermo Scientific Helios Alpha spectrophotometer (Waltham, MA, USA) in the 250 to 900 nm range using rectangular quartz cells with an optical path length of 0.0882–10 mm.
The free-base 5,10,15,20-tetraphenyl-2-(benzimidazol-2-yl)-porphyrin and 5,10,15,20-tetraphenyl-2-(N,N-dimethylbenzimidazol-2-yl)-porphyrin were prepared following the published procedure [27 (link)].