Influence of substituents on CH-π interactions in complexes involve X-acetylene and planar cyclooctatetraene

Abstract

    NMR properties of the CH-p interactions in the X-C₂H_┴C₈H₈ complexes (where _┴ denotes CH-p interaction and X = NH₂, OH, H, F, NO₂, and CN) have been investigated at the M05-2X/6-311++G** level of theory. Correlations between geometrical parameters, Hammett constants, results of atoms in molecules (AIM) analysis, charge transfer (CT), and NMR data particularly two-bond ¹³C-¹H spin-spin coupling constant ^2hJ_C-H with binding energies were considered. Also, binding energies of these complexes were compared with the X-C₆H_5┴C₈H₈ complexes to find role of acidic hydrogen of acetylene on binding energies. Results of this study aid us to better realize the nature of CH-p interactions in complexes which encompass planar cyclooctatetraene as an anti-aromatic molecule.