CH/pi Interaction in the Crystal Structure of Organic Compounds: A Database Study

The CH/pi interaction is a weak hydrogen-bond-like force occurring between CH groups and pi-groups. A study was performed by use of Cambridge Structural Database in order to obtain insight into the nature of the CH/pi interaction and to examine its role in the crystal packing. A number of short CH/pi distances was found in crystal structures of organic compounds. The CH hydrogen atoms tend to point toward the center of the aromatic ring. The CH/pai interaction was suggested to constitute one of the important factors in controlling the crystal packing of molecules.

Fig. 1. H/C inter-atomic distance for intermolecular CCH₃/Ar interaction [���n.