Quantum chemical study the on interaction between sulfanilamide drug and MgO nanocluster

The adsorption and interaction of sulfanilamide (SA) with a pristine magnesium oxide (MgO) nano-cage was scrutinized through density functional theory (DFT) calculations. All geometries were optimized at M06-2X/6-311G(d,p) level, and the single-point energy calculation was also carried out at the same level of theory. Also, natural bond orbital (NBO) analysis was carried out and the values related to Wiberg bond index (WBI), donor-acceptor interactions, and partial natural charges were inspected. The MgO nano-cage can adsorb SA more strongly with the adsorption energy (E_ads) of - 41.74 kcal/mol, corresponding to the stable configurations. In addition, NBO analysis showed that the donor-acceptor interactions with SA and the MgO nano-cage are stronger. Based on our computations, the HOMO-LUMO gap of the MgO nano-cage changed to a great extent following the adsorption of the SA molecule, which corresponds to the most stable configuration that leads to improved electrical conductivity of the MgO nano-cage. The change in the gap determines the sensing mechanism, which is associated with the change in the electrical conductivity. To calculate the recovery time, transition-state theory (TST) was employed. Based on our calculation, Mg₁₂O₁₂-SA complex composites possess a short recovery time for the desorption of SA. The results show that the MgO nano-cage is an ideal candidate to be employed for developing SA sensors with high efficiency.