@article { author = {Azayez, Mansour and Fergoug, Teffaha and Meddah-Araibi, Noureddine and Zelmat, Cherifa and Bouhadda, Youcef}, title = {Theoretical Investigation of the Complexation Reaction of Procaine-hydrochloride by β-cyclodextrin}, journal = {Physical Chemistry Research}, volume = {8}, number = {1}, pages = {155-165}, year = {2020}, publisher = {Iranian Chemical Society}, issn = {2322-5521}, eissn = {2345-2625}, doi = {10.22036/pcr.2020.205547.1691}, abstract = {Abstract. . Quantum-chemical calculations were performed to study the complexation of drug molecule procaine hydrochloride with beta cyclodextrin (β-CD) in the gas phase and in water. The inclusion process was optimized by the semi empirical method PM3 and the obtained complex structure was further refined by ONIOM method (DFT: PM3). It is found that (B3LYP/6-31G(d,p) : PM3) provides the best energy minimum for the complex, compared to M06-2X and WB97XD functional. Given the energy profile, the configuration of the complex formed indicates that the benzene ring is completely included in the hydrophobic cavity of the β-CD. The thermodynamic parameters analysis has shown that the procaine/β-CD complexation is enthalpically favorable, and the complex is well structured. Natural bond orbital (NBO) analysis indicates that no hydrogen bond interaction exists, and the procaine/β-CD complex is mainly stabilized by Van der Waals forces. 1D 1H NMR spectra analysis shows that the procaine molecule penetrates into the cavity of this CD with the aromatic ring.}, keywords = {Host-guest inclusion,Procaine,β-Cyclodextrin,PM3,1H NMR,NBO}, url = {https://www.physchemres.org/article_101501.html}, eprint = {https://www.physchemres.org/article_101501_38a192b2451189d49ba29ac506fd78db.pdf} }