1
Semnan Branch, Islamic Azad University, Semnan, Iran.
2
Department of Chemistry, Yadegar-e-Emam Branch, Islamic Azad University, Tehran, Iran.
Abstract
In this study, the effects of four substituents at two different positions of methylphenidate (MPH) drug structure were investigated on NMR and NQR tensors of carbon, nitrogen and oxygen nuclei. The obtained results were interpreted using Natural Bond Orbital (NBO) calculations based on molecular structure. The findings showed that with the increasing participation of the studied substituents in intra-molecular interactions, their impact on NMR and NQR tensors of studied nuclei increased. Therefore, electron-withdrawing substituents at positions R7 and R9 of the MPH structure, with the highest participation in intra-molecular interactions, caused the greatest increase in the resonance interactions of the benzene ring. As a result, they reduced the negative charge, the NQR tensors and chemical shielding around the adjacent nuclei and the benzene ring carbons.
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