A DFT study on the geometry, tautomerism and noncovalent interactions of the Mepivacaine drug with the pristine SWCNT and –COOH functionalized SWCNT

Abstract

The Mepivacaine drug is used as a local anesthetic in dentistry, which could exist as three different tautomers. Herein, geometry, energy behavior as well as tautomerization of these tautomers have been investigated by employing density functional theory (DFT) and considering the solvent effects with the polarizable continuum model (PCM) model. The most stable tautomer of the Mepivacaine has a carbonyl and an –NH amine groups in its structure. The frontier orbitals and the energy gap of the molecule have been computed using the natural bond orbital analysis (NBO). Also, the armchair (5,5) single wall carbon nanotube (SWCNT) was used for investigation of the noncovalent interactions of the Mepivacaine molecule with the pristine SWCNT and the –COOH functionalized SWCNT in several forms. Geometries of the possible forms have been optimized. The most stable form for noncovalent interactions of the drug with each of the pristine and functionalized SWCNTs have been determined. The intermolecular H-bonds have essential role in energy behavior of the noncovalent interactions between the Mepivacaine drug and the investigated SWCNTs.

Geometry, tautomerism and non-covalent interactions of the drug halofuginone with the carbon-nanotube and γ-Fe2O3 nanoparticles: A DFT study

“…In this work, the tautomerism of the halofuginone drug was investigated using valuable computational methods, which are useful in theoretical investigation of chemical reactions. [12][13][14][15][16][17][18][19][24][25][26][27][28][29][30][31][32][37][38][39] The relative energies of the optimized species are gathered in Table I. As could be seen, the H1a species is the most stable tautomer of halofuginone in aqueous solution.…”

“…Nowadays, nano-compounds are useful in many areas especially in drug delivery. [24][25][26][27][28][29][30][31][32][40][41][42][43] Herein, the non-covalent interaction of the H1a conformer of halofuginone with a carbon-nanotube and a magnetic γ-Fe 2 O 3 nanoparticles have been investigated using the DFT methods.…”

“…This model has good consistency with the experimental data, such as the vibration frequencies and bond lengths. 29,31,32 This model was employed in this research. The geometry of the used model for γ-Fe 2 O 3 , shown in Fig.…”

“…The covalent and non-covalent interactions of various molecules with the carbon nanotubes and iron-oxide nanoparticles have been theoretically investigated. [24][25][26][27][28][29][30][31][32] Herein, the non-covalent interactions of halofuginone with the carbon nanotubes and γ-Fe 2 O 3 nanoparticles were theoretically explored using DFT methods.…”