Computational modeling of eticyclidine drug adsorption and detection on c₆₀ based nanostructures

The detection of Eticyclidine (PCE) as a psychotropic drug is difficult due to the limitations of conventional analytical techniques (such as the need for expensive instruments, expert labor, and time-consuming). In this computational study, structural, electronic, and optical properties were evaluated to assess the ability of pristine C₆₀ fullerene and its aluminum (AlC₅₉) and zinc (ZnC₅₉) doped forms as sensors/adsorbers for PCE using density functional theory (DFT), time-dependent DFT (TD-DFT), and quantum theory of atoms in molecules (QTAIM). The calculated structural/electronic properties of pristine C₆₀ (bond lengths, energy gaps, and UV spectra) were in excellent agreement with reported experimental data, supporting the validity of the computational approach. The weak/reversible binding interaction energy, recovery times, conductivity and reactivity of pure C₆₀ indicate its suitability for repeated use as an electrochemical sensor for PCE. However, AlC₅₉ has strong and irreversible binding, indicating that it can be used as an excellent adsorbent for PCE removal. ZnC₅₉ is moderately bound to PCE compared to C₆₀ and AlC₅₉. TD-DFT calculations show a large red shift of the UV-Vis spectra when PCE is absorbed by AlC₅₉ and ZnC₅₉, which provides evidence of strong optical responses, indicating their potential for use as colorimetric sensors. The results obtained from NCI/RDG, ELF, LOL and QTAIM analyses confirm that metal doping significantly enhances the strength of the interaction with PCE. We believe that the findings of this theoretical study can provide a reliable basis for the experimental development of C₆₀-based materials for PCE sensing and adsorption.