DFT vibrational frequencies studies of acetyl-salicylic acid and Paracetamol. (2022)

• Record Type: Journal Article
• Authors: Sehrawat, Rajeev; Tyagi, D.K.; Bera, Milan K.; Mittal, Rashmi; Pandey, S.P.; Singh, O.P.; Sharma, A.K.
• Is Part Of: Materials today. Volume 49:Part 8(2022)
• Page Start: 3151
• Page End: 3154
• Publication Date: 2022
• Subjects: DFT -- IR -- Dipole moment -- Polarizability -- Acetyl-salicylic acid -- Paracetamol; Materials science -- Congresses -- Periodicals; 620.1
• DOI: 10.1016/j.matpr.2020.11.158
• Languages: English
• ISSNs: 2214-7853

Abstract

Abstract: Density functional theory DFT(B3LYP)/6-31G(d) has been applied to compute the geometry optimization, dipole moment and vibrational frequencies of acetyl-salicylic acid and paracetamol. From the comparison of vibrational frequencies it is observed that the value of O–H stretching in Aspirin is lower as compared to Paracetamol shows its greater tendency to form cation whereas paracetamol has least tendency to form cation as the O–H stretching in paracetamol, which explains that why there is displacement of –COOH by –OH group in aspirin i.e. (aspirin) acetyl-salicylic acid readily converts into salicylic acid which is responsible for most of its actions. The greater values of O–H and C–H stretching of paracetamol than Aspirin explains its selective behavior to inhibit cyclooxynase-2 (COX-2) and poor inhibitor of the synthesis of prostaglandins which is responsible for pain headache and infection and can be life saving option. On comparison of dipole moment of it is also observed that the order is) acetyl-salicylic acid > paracetamol and from our earlier ADMP studies of total energy curve vs time in trajectory curve of acetyl-salicylic acid and paracetamol at DFT/6-31G(d) it is found that the energy required to release hydrogen from these drugs are in the order paracetamol > acetyl-salicylic acid, therefore from infrared spectra, dipole moment and ADMP studies of acetyl-salicylic acid and paracetamol it is concluded that acetyl-salicylic acid is most reactive which explains that why it inhibit the synthesis of prostaglandins responsible for pain, headache and fever; restricts the blood supply to the tumor in effect- not allowing it to grow than a pea and paracetamol is a poor inhibitor of prostaglandins synthesis, does not have anti-inflammatory action. Acetyl-salicylic acid shows more reactive sites than paracetamol which give the evidence that why it is being replaced by acetyl-salicylic acid.