Substituent effect of the stacking interaction between carbon monoxide and benzene.

Noncovalent interactions (NCIs) between carbon monoxide and substituted benzene were investigated at the M06-2X/6-311++G(d,p) level. rThe results of interaction energy analysis indicated different effects for the electron-donating (-NH, -OH, -CH) and electron-withdrawing (-F, -CN, -NO) groups on the CO⋯PhX complex. Atoms in molecules analysis confirmed the NCIs between CO and PhX. NCI analysis revealed that these interactions belong to van der Waals interactions. The electron density shift of the complexes was investigated with electron density difference analysis. Ternary CO⋯PhX⋯Bz complexes were designed to study the interplay between CO⋯π and π⋯π stacking interactions.