*3.3. <sup>1</sup>H-NMR Spectra*

The <sup>1</sup>H-NMR spectra of all six π-acceptors complexes are investigated (Figure 7); while the 1H-NMR spectra of SRX only were cited previously [58]. The NH<sup>2</sup> protons of the SRX amino group are downfield displaced by 6.87–6.98 ppm as a result of the involvement of one pair of electrons on the amino group towards the six electron π-acceptors. The peaks of other aromatic and methylene protons are similarly pushed downfield to higher ppm values, indi-

*Molecules* **2022**, *27*, x 9 of 21

*Molecules* **2022**, *27*, x 9 of 21

cating the formation of six charge–transfer complexes (Supplementary Material Figure S1).

**Figure 6.** Photometric titration curves of the SRX with the six π–acceptors complex [4]. mentary Material Figure S1).

higher ppm values, indicating the formation of six charge–transfer complexes (Supple-

**Figure 6.** Photometric titration curves of the SRX with the six π–acceptors complex [4].

**Figure 7.** Best docking pose showing a helical model of dopamine docked with (**a**) [(SRX)(TCNQ)] and (**b**) [SRX].
