Abstract
The CH/π interaction is a kind of weak hydrogen bond (<1 kcal·mol-1) occurring between soft acids (CHs) and soft bases (π-electron systems). Evi-dence for such a weak attractive molecular force has been obtained by various methods, including X-ray crystallography, IR, NMR, CD spectroscopies, and combination of these methods. The conclusion has been supported by molecular orbital calculations. The characteristic features of this attractive force is that CHs and π-groups are arranged generally in chemical structures in a symmetrical manner and have many chance to interact. Moreover, the interaction may occur in protic media. The problems of conformation, chromatography, and the structure of proteins have been discussed in the light of the CH/7 interaction. Suggestions have been made, on ground of these findings, as for the applications of the concept in life science and materials science.
