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Density functional theory calculations were performed to inspect the potential application of pristine AlN nanotube (AlNNT) as well as Pd-decorated AlNNT (Pd@AlNNT) in recognition of gabapentin (GB) drug. The sensing response of AlNNT to the GB drug is very small (~ 5.2 at 298 K) attributed to the small adsorption energy (AE) of −0.16 eV. Molecular orbital energy decomposition method (EDA) showed that the contributions of electrostatic attraction, Pauli repulsion, orbital relations, and dispersion forces in the AE are about −0.21, 0.19, −0.11, and −0.09 eV, respectively. A Pd atom preferentially adsorbed over an Al–N bond of the AlNNT, releasing the energy of 2.93 eV. We found that the GB strongly adsorbed on the Pd@AlNNT with AE of −1.29 eV and the sensing response increased to 524.6 by the Pd decoration. Based on the results, the main stabilization contribution to the AE of GB on the Pd@AlNNT comes from the electrostatic attraction based on the EDA analysis. The recovery time was achieved to be 1.8 s for the GB desorption from the Pd@AlNNT surface. Finally, we concluded that the Pd@AlNNT can transform the presence of GB molecules into electrical signal, and it may potentially be applied as an electronic sensor for GB drug detection. [ABSTRACT FROM AUTHOR]

In this computational inspection, influences of substituted aluminum(s) on the vibrational frequency, infrared (IR) spectroscopy, atomic polar tensor (APT) charge, and electrostatic potential (ESP) map, along with atoms in molecules (AIM) analysis of C20 fullerene and its C20‐nAln derivatives (where n = 1–5) are investigated using B3LYP/6‐311 + G*, B3LYP/6‐311++G**, M06‐2X/6‐311++G**, B3PW91/6‐311 + G*, and B3LYP/AUG‐cc‐pVTZ. IR spectroscopy emerges that exclusive of C15Al5, the other optimized structures are global minimum without imaginary frequency. Substituting C20 to C20‐nAln heterofullerenes leads to higher APT charge distribution upon surfaces of heterofullerenes than unsubstituted species. Accordingly, the highest negative and positive APT charges on carbon and aluminum atoms of C15Al5 suggest that these sites can be attacked more readily by electrophilic and nucleophilic regents, that is, may act as the Lewis acid or Lewis base centers. This species is including five alternative aluminum heteroatoms in equatorial position and can be suitable hydrogen storage. AIM analysis of the studied C20‐nAln derivatives implies the highest ρ(r) of 0.083 a.u., the highest negative ∇2ρ(r) of −0.084 and −0.085 a.u. and the highest positive G(r)/V(r) of 4.86 and 4.69 a.u. at bond critical point of CAl bond with the strongest covalent property in the most stable C19Al1 and C17Al3 species, respectively, between studied structures. [ABSTRACT FROM AUTHOR]

DFT calculations are utilized to compare and contrast the substituted aluminum—heterofullerenes, C20-nAln (with n = 1–5) from thermodynamically view point, at density functional theory (DFT). Vibrational frequency analysis confirms that apart from C15Al5, all studied species are true minima. Considering the optimized geometries shows that all heterofullerenes are isolated-pentagon cage and none collapse to open deformed as segregated structure. The highest binding energy (5.56 eV/atom) and absolute heat of atomization (3323.68 kcal mol−1) reveals open-shell C19Al1 as the most stable thermodynamic heterofullerene. The most NICS (0) (isotropic and anisotropic parameters, −49.58 and − 46.47 ppm, respectively) introduces closed-shell C18Al2-2 as the most aromatic structure. Also, closed-shell C16Al4-1 heterofullerene emerges with the most polarizability (307.71 a.u.) and hence activity to interact with the surrounding polar species. The lowest and the highest charge transfer on the surfaces of C20 and C16Al4-2 without weak Al—Al bond, as the worst and the best candidate, respectively, provokes further investigation on impossible and possible application for hydrogen storage, respectively. We wish that the present survey will stimulate new experiments. [ABSTRACT FROM AUTHOR]