Narrow Results

The study of interaction and adsorption of drug molecules on the active surface of noble metal nanocluster is of particular interest due to effective change in the properties of the drug molecules. Surface-enhanced Raman scattering (SERS) theoretical calculations were performed to investigate the adsorption properties of pretomanid (PTD) on pyramidal ${\text{Ag}}_{20}$/${\text{Au}}_{20}$/${\text{Cu}}_{20}$ metal clusters. The charge transfer process from the $M_{20}$ pyramids is revealed by MEP and electronic analysis. The frequencies of PTD are enhanced in the PTD–metal complexes due to the noticeable SERS effect, and the binding energies were calculated to be −36.2 kcal/mol, −46.3 kcal/mol and −43.6 kcal/mol with Ag, Au and Cu structures, respectively. For the PTD–metal clusters, there is an entire potential rearrangement due to adsorption process which is due to charge transfer and adsorptions as chemisorption. The polarizability variations are predicted in the order PTD–Au > PTD–Cu > PTD–Ag which contribute the SERS enhancement due to adsorption. Changes in thermodynamic parameters reveal that adsorption is exothermic and at the same time spontaneous with ordered interactions due to the negative values. There is a redshift for the ultraviolet–visible (UV–vis) absorption of PTD–metal complexes with a lowering intensity in comparison with that of PTD, more likely indicating a chemisorption process. SERS enhancement factors are remarkable due to adsorption of conformationally flexible PTD on metal clusters. The noncovalent interactions between PTD and the metal pyramids were also determined. The study provided key information on designing a molecular structure with a good pharmacological profile by calculating bioactivity and drug similarity parameters for bioactive drug molecules.

Using first principles, the electrical response of carbon nanocones (NC) to the drug benzamide (BZE) was investigated using density functional theory (DFT). The adsorption energies of BZE at the nanocone’s bottom (Complex I), side (Complex II), and top (Complex III) are −88.35 kcal/mol, −45.46 kcal/mol and −48.73 kcal/mol. The two other adsorptions, Complexes II and III are physisorption, however, the high value of Eads in the case of Complex I with the drop in bond lengths suggests that Complex I adsorption is chemisorption. The electrical conductivity has risen as a result of the considerable decrease in the nanocone energy gap (from 0.63 eV to 0.61 eV, 0.61 eV and 0.60 eV) caused by the adsorption of BZE. It suggests that the nanocones would be a good fit for the electronic sensors and an appropriate choice for BZE detection. Additionally, the BZE adsorption influences the nanocone’s workfunction, which is reduced by approximately 45.19%, 2.8% and 2.05% for complexes I to III. This suggests that the nanocone could be a workfunction-based sensor for the detection of BZE. The increase in binding affinity in complexes reveals that the nanocones will act as a drug delivery carrier. Theoretically, anticipated Raman spectra of BZE and complexes show SERS activity and inactive normal Raman modes are active in the Raman spectrum of complexes. Compounds II and III exhibit weak noncovalent interactions (NCI) and due to the presence of covalent bonding interaction in compound I, significant changes in other bonding and nonbonding electron densities are observed compared to compounds II and III.