DFT Study of the Monomers and Dimers of 2-Pyrrolidone:  Equilibrium Structures, Vibrational, Orbital, Topological, and NBO Analysis of Hydrogen-Bonded Interactions

Abstract

A computational study of the monomers and hydrogen-bonded dimers of 2-pyrrolidone was executed at different DFT levels and basis sets. The above dimeric complexes were treated theoretically to elucidate the nature of the intermolecular hydrogen bonds, geometry, thermodynamic parameters, interaction energies, and charge transfer. The processes of dimer formation from monomers and concerted reactions of double proton transfer were considered. The evolution of geometry, vibrational frequencies, charge distribution, and AIM properties in going from monomers to dimers was systematically followed. The solvent effects upon dimer formation were investigated in terms of the self-consistent reaction field (SCRF Onsager model). For the monomers and three dimers, vibrational frequencies were calculated and the changes in frequencies of the vibrations most sensitive to complexation were discussed. The orbital interactions were shown to lengthen the X-H (X = N, O) bond and lower its vibrational frequency (a red shift). To better understand the nature of the corresponding intermolecular interactions, we performed natural bond orbital (NBO) analysis. Topological analysis of electron density at bond critical points (BCP) was executed for complex molecules using the Bader's atoms in molecules (AIM) theory. The interaction energies were calculated, and the basis set superposition errors (BSSE) were estimated systematically. Satisfactory correlations between the structural parameters, interaction energies, and electron density characteristics at BCP were found.

Experimental, DFT dimeric modeling and AIM study of H-bond-mediated composite vibrational structure of Chelidonic acid

“…Further, we tested this premise by performing calculation at BP86/6-31G(d) level as well, yielding satisfactory frequency values for the dimer species (see Table S4). Notwithstanding, the advantage of B3LYP/6–311++G(d,p) level will be evident in AIM analysis to be discussed later where computed values of ρ( r ) and its Laplacian ∇ 2 ρ( r ) are more closer to the results reported in the literature [57, 58].

Fig.

…”

Acidity and basicity interplay in amide and imide self-association

“…First, we studied the dimerisation of 2-pyrrolidone ( A1 ), an archetype for the study of the self-association of the functional groups concerned in this investigation, 7b , 20 in different deuterated solvents such as chloroform- d , acetonitrile- d 3 and DMSO- d 6 , and also considered the reported value in CCl 4 in order to select the most suitable solvent for this research. Another feature of 2-pyrrolidone which makes it particularly suitable for this purpose is the fact that it is liquid at room temperature and thereby its self-association is easier to study in deuterated solvents which cover a broad range of polarity.…”

Stabilization of diketo tautomer of curcumin by premicellar anionic surfactants: UV–Visible, fluorescence, tensiometric and TD-DFT evidences

“…All the calculations have been carried out using hybrid functional B3LYP (Becke exchange with Lee, Yang and Parr correlation) [44][45][46] and 6-31+g(d,p) basis set for all the atoms as implemented Gaussian 03 program package. The B3LYP functional has been chosen because it is one of the appropriate functional [47][48][49] for the prediction of the structures of different chromophores. In this work, the computational results for curcumin in presence of SDS only have been presented as a case study for anionic surfactant.…”