LAUSR

Abstract The small organic molecules involving −CN group often constitute the building block of the biological systems and liquid solvents of strong dipole moment appreciated for organic synthesis. Among them, benzonitrile liquid has been proposed to be used as a co-solvent with green chemistry ionic liquids. In the first part of the series of researches, we present the study of benzonitrile clusters (up to tetramer) in gas and liquid phase (PCM) by density functional theory. We focus on unraveling and characterizing the interactions effective in the liquid benzonitrile, where dipole-dipole interaction has been already known as the majorly influential. By including clusters up to tetramers and studying their binding energies, identifying hydrogen bondings, verifying the possible (energy minima) structure of each cluster, elucidating and confirming the nature of hydrogen bonding (using AIM and NBO methods), assigning the stretching modes and shift in frequencies of C≡N group (IR Spectrum), and the thermodynamics stabilities, it is found quantitatively that hydrogen bondings, in addition to the dipole-dipole interaction already claimed as the main intermolecular interaction, play roles chiefly in stabilizing the clusters.