Density functional theory investigation of cocaine water complexes

作者：Senthilkumar Lakshmipathi^*; Umadevi Palanivel; Nithya Kumaranathapuram Natarajan Sweety; Kolandaivel Ponmalai

来源：Journal of Molecular Modeling, 2013, 19(8): 3411-3425.

DOI：10.1007/s00894-013-1866-0

• Blue shift
• Cocaine
• Density difference plot
• DFT
• NBO analysis
• Red shift

Twenty cocaine-water complexes were studied using density functional theory (DFT) B3LYP/6-311++G** level to understand their geometries, energies, vibrational frequencies, charge transfer and topological parameters. Among the 20 complexes, 12 are neutral and eight are protonated in the cocaine-water complexes. Based on the interaction energy, the protonated complexes are more stable than the neutral complexes. In both complexes, the most stable structure involves the hydrogen bond with water at nitrogen atom in the tropane ring and C = O groups in methyl ester. Carbonyl groups in benzoyl and methyl ester is the most reactive site in both forms and it is responsible for the stability order. The calculated topological results show that the interactions involved in the hydrogen bond are electrostatic dominant. Natural bond orbital (NBO) analysis confirms the presence of hydrogen bond and it supports the stability order. Atoms in molecules (AIM) and NBO analysis confirms the C-H center dot center dot center dot O hydrogen bonds formed between the cocaine-water complexes are blue shifted in nature.

• 出版日期2013-8