DFT CALCULATIONS IN MONOMERIC AND DIMERIC FORMS OF N-BENZYLMALEIMIDE (NBM) COMBINED WITH VIBRATIONAL SPECTROSCOPIC PARAMETERS


Arı H.

Eskişehir Teknik Üniversitesi Bilim ve Teknoloji Dergisi B - Teorik Bilimler, cilt.11, sa.1, ss.70-90, 2023 (Hakemli Dergi)

Özet

The structural, vibrational and theoretical analyses of N-benzylmaleimide (NBM) having chemical and biological significances have been made. The four possible conformers and their sixty-six dimeric forms linked by the intermolecular C=O···H hydrogen bonding were investigated for the stability. The conformational and the dimeric structures of NBM in the gas phase were investigated and the population distributions of the conformations and dimers were obtained using the Boltzmann distribution. The experimental IR and Raman spectra of solid phase NBM were recorded, and the bands were compared with the theoretical wavenumber the values of the monomer and the dimer forms for their assignments. The new scale factors (0.9617 for B3LYP/6-31G(d) and 0.9531 for M06-2X/6-31G(d)) obtained for NBM can be used more accurately in vibration calculations of all maleimide derivatives. The Molecular Electrostatic Potential (MEP) map showed that the negative and the positive regions have changed from monomeric to dimeric form changes, while the HOMO-LUMO shapes did not generally change in monomeric and dimeric forms. The nucleophilic and electrophilic Fukui functions and dual descriptors shows that maleimide and benzyl groups are nucleophilic and electrophilic regions, respectively, additionally the dual descriptor values decrease upon dimerization.