DFT computational analysis of piracetam

•The UV–Visible spectra were recorded and analyzed for the compound.•Quantum chemical calculation DFT using 6-31G(d,p) and 6-31++ basis set were carried out.•The first order hyperpolarizability, NBO, MEP and HOMO, LUMO energy gap were theoretically predicted.•Global and local descriptors and thermodynamic properties of piracetam are calculated.

Density functional theory calculation with B3LYP using 6-31G(d,p) and 6-31++G(d,p) basis set have been used to determine ground state molecular geometries. The first order hyperpolarizability (β0) and related properties (β, α0 and Δα) of piracetam is calculated using B3LYP/6-31G(d,p) method on the finite-field approach. The stability of molecule has been analyzed by using NBO/NLMO analysis. The calculation of first hyperpolarizability shows that the molecule is an attractive molecule for future applications in non-linear optics. Molecular electrostatic potential (MEP) at a point in the space around a molecule gives an indication of the net electrostatic effect produced at that point by the total charge distribution of the molecule. The calculated HOMO and LUMO energies show that charge transfer occurs within these molecules. Mulliken population analysis on atomic charge is also calculated. Because of vibrational analysis, the thermodynamic properties of the title compound at different temperatures have been calculated. Finally, the UV–Vis spectra and electronic absorption properties are explained and illustrated from the frontier molecular orbitals.

Graphical abstractIn this work, we report a theoretical study on molecular structure, NBO/NLMO, MEP, thermodynamic properties and UV–Visible spectral analysis of piracetam. The molecular geometry, harmonic vibrational frequencies and bonding features of piracetam in the ground-state have been calculated by using the density functional method B3LYP with 6-31G(d,p) and 6-31++G(d,p) basis sets. Stability of the molecule arising from hyperconjugative interactions, charge delocalization has been analyzed using natural bond orbital (NBO) analysis. The results show that charge in electron density (ED) in the σ* antibonding orbitals and E(2) energies confirms the occurrence of ICT (Intra-molecular Charge Transfer) within the molecule. The UV spectrum was measured in water as a solvent. The calculated HOMO and LUMO energies show that charge transfer occurs within the molecule.Figure optionsDownload full-size imageDownload as PowerPoint slide