CH/pi hydrogen bonds in organic and organometallic chemistry

This treatise is an update to a preceding highlight (CH/pi hydrogen bonds in crystals) published in this journal 5 years ago (M. Nishio, CrystEngComm, 2004, 6, 130-156). After the introductory part (sections 1 and 2), we survey recent results (mostly since 2004) relevant to the CH/pi hydrogen bond: crystal conformation, packing and host/guest chemistry (section 3). Section 4 summarizes the results obtained by crystallographic database (CSD and PDB) analyses. In section 5, several topics in related fields (selectivity in organic reactions, surface chemistry, structural biology, drug design and high-level ab initio calculations of protein/substrate complexes and natural organic compounds) are introduced, and in the final part we comment on the prospects of this emerging field of chemistry.