## 4 Conclusions  
In summary, two new zinc(II) tribenzoporphyrazines with sulfanyl substituents were obtained and subjected to various photophysical measurements as well as an initial acute toxicity assessment. The results were compared to their magnesium(II)-containing counterparts. The synthesis started from obtaining a maleonitrile derivative according to the published procedure, then using this compound and the excess of 1,2-dicyanobenzene in [PERSON]'s macrocyclization reaction conditions resulted in the formation of magnesium(II) tribenzoporphyrazine with 4-(3,5-dibutoxycarbonylphenoxy)butylthio substituents. Next, the magnesium derivative was demetallated with trifluoroacetic acid and subsequently remetallated with zinc(II) acetate toward zinc(II) tribenzoporphyrazine. The next step of the synthesis was the peripheral modification, as zinc(II) tribenzoporphyrazines was subjected to a reduction reaction with LiAlH\({}_{4}\), which led to zinc(II) tribenzoporphyrazine with 4-[3,5-di(hydroxymethyl)]phenoxyylbutylthio substituents. The new zinc(II) tribenzoporphyrazines were characterized by UV-Vis spectroscopy, various NMR techniques (1 HNMR, 13 CNMR, 1H-1H COSY, 1H-13C HSQC, and 1H-13C HMBC), and mass spectrometry. The UV-Vis spectra of the new macrocycles were recorded in different solvents and subjected to a solvatochromic study in which the positions of the Q-bands of each solvent were analyzed. Both macrocycles were studied using electrochemical measurements. In the voltamogram of zinc(II) tribenzoporphyrazine with 4-(3,5-dibutoxycarbonylphenoxy)butylthio substituents, two reduction peaks and one oxidation peak were observed in the electrochemical window between \(-\)2.0 V and +1.0 V, whereas the second oxidation peak was not noted in the CV scans. The evolution of this peak was observed at the boundary of the electrochemical window in the DPV scan. The CV and DPV studies of zinc(II) tribenzoporphyrazine with 4-[3,5-di(hydroxymethyl)]phenoxyylbutylthio substituents revealed four redox peaks: two reductions and two oxidations in the analyzed potential window. The electrochemical bandgap, E\({}_{\text{gap}}\), of both zinc(II) tribenzoporphyrazines presented the same value of 1.5 eV. What is more, all oxidation and reduction processes for both macrocycles were diffusion-controlled due to a linear correlation of the peak currents of the redox pairs versus the square root scan rate. In the photochemical assessment of the singlet oxygen generation, both zinc(II) tribenzoporphyrazines revealed moderate to high quantum yield generation values of 0.24 and 0.59 in DMSO. The results of the Microtox(r) bioluminescence  
Figure 9: Changes in the _Aliiibrio fischeri_ cell viability upon exposure to the tested porphyazines **3**, **4**, **6**, and **7** at 10\({}^{-4}\) or 10\({}^{-5}\) concentrations. assay showed that the newly obtained zinc(II) macrocycles can be regarded as potential photosensizers for further applications in medicine, while the electrochemical assessment proved that these molecules may be regarded as useful for new technology development. The following are available online at [[https://www.mdpi.com/article/10.3390/app12136825/s1](https://www.mdpi.com/article/10.3390/app12136825/s1)]([https://www.mdpi.com/article/10.3390/app12136825/s1](https://www.mdpi.com/article/10.3390/app12136825/s1)). Figure S1. NMR data of **6**: \({}^{1}\)H and (\({}^{13}\)C) chemical shift values [ppm] and key correlations observed in NMR spectra. Bold lines: \({}^{1}\)H-\({}^{13}\)C COSY; Arrows: \({}^{1}\)H-\({}^{13}\)C HMBC. Figure S2. NMR data of **7**: \({}^{1}\)H and (\({}^{13}\)C) chemical shift values [ppm] and key correlations observed in NMR spectra. Bold lines: \({}^{1}\)H-\({}^{1}\)H COSY; Arrows: \({}^{1}\)H-\({}^{13}\)C HMBC. Table S1. \({}^{1}\)H and \({}^{13}\)C NMR data obtained for **6** including key correlations determined from \({}^{1}\)H-\({}^{1}\)H COSY, \({}^{1}\)H-\({}^{13}\)C HSQC and \({}^{1}\)H-\({}^{13}\)C HMBC spectra. Table S2.