Technical grade silica gel

NMR spectroscopy (¹H, ¹³C) was conducted on either a Bruker DPX-300 or Bruker DPX-400 spectrometer, and all chemical shifts (δ) are given in ppm relative to the solvent reference. The data are recorded as follows: chemical shift (multiplicity (s for singlet, d for doublet, t for triplet, m for multiplet, and br for broad), coupling constant(s) J are quoted in Hz). Mass spectroscopy was obtained using a Bruker HCT Ultra machine. TLCs were performed on Merck silica gel 60 F-254 TLC sheets and were visualized by staining with 10% H₂SO₄ in ethanol followed by heating. Flash chromatography was carried out using Sigma–Aldrich technical grade silica gel (pore size, 60 Å; particle size, 40–63 μm) as the stationary phase.

All reagents for synthesis were purchased from commercial sources and were used without further purification. Analytical thin layer chromatography (TLC) was carried out using Merck (Darmstadt, Germany) TLC Silica gel 60 F₂₅₄ aluminium sheets and visualized under UV or by appropriate stain. P-anisaldehyde and potassium permanganate were the most used. Column chromatography was carried out using Sigma Aldrich (Darmstadt, Germany) technical grade silica gel (pore size 60 Å, 230–400 mesh particle size, 40–63 μm particle size). In the experiments to determine the chelating ability of the compound, aqueous solutions of buffers, metals, pyrocatechol violet (C₁₉H₁₄O₇S, Sigma Aldrich, Darmstadt, Germany), and ferrozine (C₂₀H₁₃N₄NaO₆S₂, 97.0%, Sigma-Aldrich, Darmstadt, Germany) were prepared using ultrapure water (Simplicity^® Water Purification System, Merck, Darmstadt, Germany, 18.2 MΩ.cm). 3CdSO₄.8H₂O (98%), CuSO₄.5H₂O (p.a, 99%), and FeSO₄.7H₂O (p.a, 99%) were purchased from Alfa Aesar, Riedel-de-Haën and Merck (Darmstadt, Germany), respectively. Ligand solution was prepared in dimethyl sulfoxide (99.5%, LAB-SCAN Ltd., Poland). Absolute ethanol (99.8%, Honeywell, Charlotte, NC, USA) was used to prepare the solution of 5,7-Dibromo-8-hydroxyquinoline (97%, Alfa Aesar, Karlsruhe, Germany).

All reagents for synthesis were purchased from commercial sources and used without further purification. Analytical thin layer chromatography (TLC) was carried out using Merck (Darmstadt, Germany) TLC Silica gel 60 F254 aluminum sheets and visualized under UV or by appropriate stain. P-Anisaldehyde and potassium permanganate were the most used. Column chromatography was carried out using Sigma Aldrich (Darmstadt, Germany) technical grade silica gel (pore size 60 Å, 230–400 mesh particle size, 40–63 μm particle size).