Structural, vibrational, electronic, NMR and reactivity analyses of 2-amino-4H-chromene-3-carbonitrile (ACC) by ab initio HF and DFT calculations

This study represents an integrated approach towards understanding the vibrational, electronic, NMR, reactivity and structural aspects of 2-amino-4H-chromene-3-carbonitrile (ACC). A detailed interpretation of the FT IR, UV and NMR spectra were reported. Theoretical calculations were performed by ab initio HF and density functional theory (DFT)/B3LYP method using 6-311 + +G(d,p) basis sets. The electronic properties was also studied and the most prominent transition corresponds to π → π*. The lower frontier orbital energy gap and high dipole moment illustrates the high reactivity of the title molecule. The NMR results indicated that the observed chemical shifts depend not only on the structure of the molecule being studied, but also on the solvent used. ACC exhibited good nonlinear optical activity and was much greater than that of urea. Molecular electrostatic potential (MEP) results predicted that the enaminonitrile fragment of ACC to be the most reactive site for both electrophilic and nucleophilic attack. In addition, the thermodynamic properties of the compound were calculated at different temperatures and corresponding relations between the properties and temperature were also studied.

Graphical abstractThis study represents an integrated approach towards understanding the vibrational, electronic, NMR, reactivity and structural aspects of 2-amino-4H-chromene-3-carbonitrile (ACC). A detailed interpretation of the FT IR, UV and NMR spectra were reported. Theoretical calculations were performed by ab initio HF and density functional theory (DFT)/B3LYP method using 6–311 + +G(d,p) basis sets. The lower frontier energy gap and high dipole moment illustrates the high reactivity of the molecule and the most prominent transition corresponds to π → π*. The NMR results indicated that the observed chemical shifts depend not only on the structure of the molecule being studied, but also on the solvent used. ACC exhibited a good nonlinear optical activity and was four times greater than that of urea. Molecular electrostatic potential (MEP) results predicted the enaminonitrile fragment of ACC to be the preferred reactive site for both electrophilic and nucleophilic attack. In addition, the thermodynamic properties of the compound were calculated at different temperatures and corresponding relations between the properties and temperature were also studied.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► The structure, vibrational, NMR and chemical reactivity of 2-amino-4H-chromene-3-carbonitrile (ACC) was studied. ► The total dipole moment, MEP and thermodynamic properties of the compound were also calculated. ► ACC exhibited good NLO activity. ► Enamino nitrile fragment of ACC would be the most reactive site.