Avance 400 ft spectrophotometer

All reagents of commercial quality were used without further purification. The purity of the compounds was determined by elemental analysis and verified to be ≥95%. NMR spectra were recorded at 25°C on a Bruker Avance 400 FT spectrophotometer. The attenuated total reflectance IR spectra were recorded by means of a Nicolet-Nexus (Thermo Fisher) spectrophotometer by using a diamond crystal plate in the range of 4000–400 cm^-1. Elemental analyses were performed by using a FlashEA 1112 series CHNS/O analyzer (Thermo Fisher) with gas-chromatographic separation. Electrospray mass spectral analyses (ESI-MS) were performed with an electrospray ionization (ESI) time-of-flight Micromass 4LCZ spectrometer. MS spectra were acquired in positive EI mode by means of a direct exposure probe mounting on the tip of a Re-filament with a DSQII Thermo Fisher apparatus, equipped with a single quadrupole analyzer.

Chemicals for synthesis were purchased from Sigma-Aldrich Srl (Milano, Italy) and used without further purification. The purity of the compounds was determined by elemental analysis and verified to be ≥ 95%. ¹H-NMR spectra were obtained in a 5 mm NMR precision tube at 298 K on a Bruker Avance 400 FT spectrophotometer. Elemental analyses were performed by using a FlashSmartCHNS analyser (Thermo Fisher) with gas-chromatographic separation. The MS spectra were recorded in methanol and acquired in positive EI mode by means of a DEP-probe (Direct Exposure Probe) mounting on the tip of a Re-filament with a DSQII Thermo Fisher apparatus, equipped with a single quadrupole analyser or performing an ESI–MS analysis using a Waters Acquity Ultraperformance ESI–MS spectrometer with Single Quadrupole Detector.
The synthesis of the TSs (Fig. 1) was accomplished following a protocol we have previously reported^{29 (link),31 (link)}. Briefly, the aldehyde was dissolved in hot ethanol and added of few drops of glacial acetic acid. An equimolar amount of the proper thiosemicarbazide was added to the solution and the reaction was heated under reflux for 4–6 h. The solution was cooled r.t. and the TSs were isolated as solids by filtration, washed several times with cold ethanol and ether and then dried under vacuum.

All reagents of commercial quality were purchased from Sigma-Aldrich and used without further purification. The purity of the compounds was determined by elemental analysis and verified to be ≥95% for all synthesized molecules. NMR spectra were recorded at 25 °C on a Bruker Avance 400 FT spectrophotometer. The attenuate total reflectance IR spectra were recorded by means of a Nicolet-Nexus (Thermo Fisher) spectrophotometer by using a diamond crystal plate in the range of 4000–400 cm⁻¹. Elemental analyses were performed by using a FlashEA 1112 series CHNS/O analyzer (Thermo Fisher) with gas-chromatographic separation. Electrospray mass spectral analyses (ESI-MS) were performed with an electrospray ionization (ESI) time-of-flight Micromass 4LCZ spectrometer. MS spectra were acquired in positive EI mode by means of a direct exposure probe mounting on the tip of a Re-filament with a DSQII Thermo Fisher apparatus, equipped with a single quadrupole analyzer. UV–Vis spectra were recorded on an Evolution 260 Bio Thermo spectrophotometer by using cells of 1 cm path length. UV-vis absorption spectra of 19 and 23 were registered using a ca. 10⁻⁵ M solution in methanol. Each metal/ligand system was studied by titrating a 2.8 ml sample of the ligand solution with a methanolic solution of Mg(CH₃COO)₂; 8–12 spectra of samples with M:L molar ratio ranging from 0 to 6 were measured.