DFT investigation of boron- and zinc-doped C24 fullerenes as efficient nanosensors for molly detection

Reliable detection of 3,4-methylenedioxymethamphetamine (Molly) remains a major analytical challenge due to its widespread recreational use and high risk of combination with toxic substances, as well as the limitations of conventional laboratory methods such as GC-MS and Raman spectroscopy. This study employs Density Functional Theory (DFT), Time-Dependent DFT (TD-DFT), Quantum Theory of Atoms in Molecules (QTAIM), Natural Bond Orbital (NBO), and Non-Covalent Interaction (NCI) analyses to design and evaluate pristine and doped C24 fullerenes (BC23 and ZnC23) as potential colorimetric and electrochemical nanosensors for Molly detection. Computational findings reveal that boron and zinc doping enhance structural stability, with cohesive energies increasing from 149 kcal mol− 1 (C24) to 194 kcal mol− 1 (BC23) and 188 kcal mol− 1 (ZnC23). Electronic analysis shows that doping reduces the HOMO-LUMO gap from 6.12 eV (C24) to 5.68 eV (BC23) and 5.24 eV (ZnC23), improving reactivity and charge transfer. The BC23@Molly complex (Conformer 4) exhibited the highest adsorption energy (− 18.19 kcal mol− 1) and a remarkable redshift in λmax from 444 to 660 nm, confirming its superior colorimetric sensitivity. Conversely, the ZnC23@Molly complex (Conformer 6) demonstrated the fastest recovery time (3.8 × 10− 4 s) and highest electrical conductivity (2.78 × 109 A m− 2), identifying it as the most efficient electrochemical sensor. QTAIM and NCI analyses confirmed the presence of medium-strength hydrogen bonding and dispersive interactions, while NBO data revealed strong π→π (21.13 kcal mol− 1)* and LP→π (55.97 kcal mol− 1)* transitions in BC23@Molly. Collectively, these results establish BC23 as the most effective colorimetric sensor and ZnC23 as the optimal electrochemical sensor for rapid, sensitive, and field-deployable Molly detection.