## 3 Results and Discussion  
### Chemistry  
#### 3.1.1 Synthesis of Compounds  
In regard to the objectives set, the molecules were synthesized as follows (Figure 4). Lipophilic 3-(trifluoromethylomethyl)phenyl isocyanate (**1**), as a convenient starting compound, was treated with (\(\pm\))-(oxiran-2-yl)methanol (**2**) providing white crystalline (\(\pm\))-(oxiran-2-yl)methyl- [1-(3-trifluoromethylomethyl)phenyl]carbamate (**3**). The yield of given nucleophilic addition was satisfactory (81%). The opening of an (\(\pm\))-(oxiran-2-yl)methyl ring of **3** was made via nucleophilic addition with particular 1-(substituted phenyl)-/1-(dimethylphenyl)piperazine (**4a-g**) available commercially [30; 52]. The desired oily carbamates (**5a-g**) were obtained with good yields from 75% (**5f**) to 85% (**5g**).  
The bases dissolved in chloroform were converted into required piperazinium chloride salts (**6a-g**). In order to obtain pure target compounds for further analytical, physicochemical, and in vitro biological evaluations, they were crystallized from propan-2-ol twice. Thus,final substances were achieved with moderate to low yields only, i.e., from 55% (**6g**) to 31% (**6c**).  
The molecules **6a-g** were defined comprehensively with appropriate descriptors from IR, 1H NMR, 13C NMR, and 19F NMR as well as HPLC-UV/HR-MS (ESI) spectral analyses, and these data confirmed the proposed structures. Considering the IR spectra interpretation (Supplementary Materials), the bands from 1740 (**6f**) to 1722 cm\({}^{-1}\) (**6c**) were observed as typical ones for stretching vibrations, \(v\) (C=O). The phenyl moieties were indicated with \(v\) (C=C) at approximately 1605 cm\({}^{-1}\). The vibrations at approximately 1512 cm\({}^{-1}\) were observed as \(\delta\) (N-H) was present. The bands between 1245 and 1242 cm\({}^{-1}\) corresponded to asymmetric stretching of the C-O-C arrangement of bonds. The =C-H group afforded in-plane deformation vibrations (\(\delta_{\text{ip}}\)) approximately at 1020 cm\({}^{-1}\) and, in addition, its out-of-plane deformation vibrations (\(\delta_{\text{oop}}\)) approximately at 845 cm\({}^{-1}\) were also noticed. In 1H NMR (Supplementary Materials), the proton signal of a protonated cyclic piperazin-1-ium-1,4-diyl moiety was observed as a singlet in the \(\delta\) interval from 10.95 (**6b**) to 10.46 ppm (**6g**). The proton signal of an NHCOO group was observed as a singlet from 10.24 (**6a**) to 9.99 ppm (**6c**). Following the 13C NMR spectral data (Supplementary Materials), all carbons were confirmed in agreement with the proposed structures. The signal of fluorine within a CF\({}_{3}\) group was observed from -60.14 (**6b**) to -60.20 ppm (**6c**) in 19F NMR. Heteronuclear coupling of fluorine atoms to 1H NMR and 13C NMR was also observed (Supplementary Materials). The protonation of only one \(N\) atom of piperazin-1-ium-1,4-diyl was observed within the structure of 6a-g (Figure 4). The finding was supported by HPLC-UV/HR-MS, where particular [M+H]\({}^{+}\) molecular peaks for these solid molecules were found (Supplementary Materials).  
The purity evaluation of all salts was carried out using the LC-UV/HR-MS method. Their satisfactory purity, varying from 97.34% (**6a**) to 98.85% (**6g**; Supplementary Materials), was achieved by repeated crystallization as listed in previous sections.