DFT-D4 Insight into the Inclusion of Amphetamine and Methamphetamine in Cucurbit[7]uril: Energetic, Structural and Biosensing Properties

Abstract

The host–guest interactions of cucurbit[7]uril (CB[7]) as host and amphetamine (AMP), methamphetamine (MET) and their enantiomeric forms (S-form and R-form) as guests were computationally investigated using density functional theory calculations with the recent D4 atomic-charge dependent dispersion corrections. The analysis of energetic, structural and electronic properties with the aid of frontier molecular orbital analysis, charge decomposition analysis (CDA), extended charge decomposition analysis (ECDA) and independent gradient model (IGM) approach allowed to characterize the host–guest interactions in the studied systems. Energetic results indicate the formation of stable non-covalent complexes where R-AMP@CB[7] and S-AMP@CB[7] are more stable thermodynamically than R-MET@CB[7] and S-MET@CB[7] in gas phase while the reverse is true in water solvent. Based on structural analysis, a recognition mechanism is proposed, which suggests that the synergistic effect of van der Waals forces, ion–dipole interactions, intermolecular charge transfer interactions and intermolecular hydrogen bonding is responsible for the stabilization of the complexes. The geometries of the complexes obtained theoretically are in good agreement with the X-ray experimental structures and indicate that the phenyl ring of amphetamine and methamphetamine is deeply buried into the cavity of CB[7] through hydrophobic interactions while the ammonium group remains outside the cavity to establish hydrogen bonds with the portal oxygen atoms of CB[7].

Enhanced adsorptive removal of indigo carmine dye by bismuth oxide doped MgO based adsorbents from aqueous solution: equilibrium, kinetic and computational studies

“…22 Magnesium bismuth oxides composites with silver iodide were prepared by Dai et al, as a photocatalytic active agent to remove some dyes from water, the composite showed a performance of 92.3-99.5% degradation within 10 min under visible light irradiation. 23 The use of density functional theory has become increasingly common among chemists, providing them with a useful tool to study the mechanism of interaction between two chemical species 24,25 in particular the adsorption of molecules on the surface of a solid, [26][27][28][29] thus the rationalization of the doping mechanism of some metal oxides. [30][31][32] The current study aims to fabricate magnesium bismuth oxide nanoparticles in different proportions and explore their removal capacities as environmentally safe sorbent for removing indigo carmine hazardous dye.…”

DFT Investigation on the Complexation of β-Cyclodextrin and Hydroxypropyl-β-Cyclodextrin as Recognition Hosts with Trichloroethylene

“…ECDA analysis indicates that the net computed charges transferred from TCE to β-CD and HP-β-CD during the formation of the TCE@β-CD and TCE@HP-β-CD complexes are 0.146 and 0.111, respectively. This suggests that charge transfer contributes to the enhancement of the stability of both complexes [61,62]. The IGM isosurface (isovalue 0.002 a.u.)…”

Comprehensive Evaluation of End-Point Free Energy Techniques in Carboxylated-Pillar[6]arene Host-guest Binding: I. Standard Procedure

“…The normal mode approximation has been widely used in various cases such as static quantum mechanics calculations and protein-protein binding. [91][92][93][94][95][96][97][98][99] Due to the popularity of NMA in end-point free energy analysis of protein-ligand and host-guest systems, in the current benchmark calculation, we select this 'standard' method to estimate the entropic contribution to the binding free energy. As the computational cost of NMA calculations (specifically the calculation of the Hessian matrix) is quite high in complex systems and the entropic changes from NMA are similar for different configurations, often only several or tens of snapshots are used to compute this term.…”