8 hydroxy 2 quinolinecarboxaldehyde

8-Hydroxy-2-quinolinecarboxaldehyde,
1-(2-aminoethyl)-piperidine, 4-(2-aminoethyl)morpholine, and 3-morpholinopropylamine
were purchased from Sigma-Aldrich. 4-(2-Hydroxy ethyl)-1-piperazine
ethanesulfonic acid (HEPES) was obtained from Sigma-Aldrich, and KCl,
KOH, HCl, ethylenediamine tetraacetic acid (EDTA), and potassium hydrogen
phthalate were obtained from Reanal (Hungary). All products were used
without further purification. ZnCl₂ and CuCl₂ were purchased from Thermo Scientific and BDH Chemicals, respectively.
CuCl₂ and ZnCl₂ stock solutions were prepared
by the dissolution of anhydrous CuCl₂ and ZnCl₂ in water; their concentrations were determined by complexometry
with EDTA. The water used in all biological studies was double-deionized
in a Milli-Q system (Millipore). All of the remaining chemicals used
were of analytical grade.

All common laboratory chemicals were purchased from commercial sources and used without further purification: 8-hydroxy-2-quinolinecarboxaldehyde, ≥96% (Sigma-Aldrich, St. Louis, MO, USA); thiosemicarbazide, ≥99.9% (Fluka, Buchs, Switzerland); 4-methyl-3-thiosemicarbazide, 97% (Fluorochem, Hadfield, UK); 4,4-dimethyl-3-thiosemicarbazide, ≥98.0% (TCI, Tokyo, Japan); 4-phenyl-3-thiosemicarbazide, 99% (Sigma-Aldrich); gallium nitrate hydrate, 99.9% (Sigma-Aldrich); indium nitrate hydrate, 99.9% (Sigma-Aldrich). NMR was recorded on a Bruker Anova spectrometer at 400 MHz (Billerica, MA, USA), with chemical shift reported in δ units (ppm). NMR spectra were referenced relative to residual NMR solvent peaks. The solvent used in the spectra’s acquisitions is DMSO-d₆. The FT-IR measurements were recorded on Nicolet 5PC FT-IR (Rodano, MI, Italy) in the 4000–400 cm⁻¹ range, equipped with the ATR accessory. Elemental analyses were performed using the Thermofisher Scientific Flashsmart CHNS Elemental Analyzer (Rodano, MI, Italy). ESI-MS were recorded on a Waters Acquity Ultraperformance ESI-MS spectrometer with a Single Quadrupole Detector (Sesto San Giovanni, MI, Italy). UV/Vis spectra were collected using a Thermofisher Scientific Evolution 260 Bio Spectrophotometer (Rodano, MI, Italy), using quartz cuvettes of 1 cm path length.