Statistical analysis of σ-holes: a novel complementary view on halogen bonding

To contribute to the understanding of noncovalent binding of halogenated molecules with biological activity, electrostatic potential (ESP) maps of more than 2500 compounds were thoroughly analysed. A peculiar region of positive ESP, called the sigma-hole, is a concept of central importance for halogen bonding. We aim to simplify the view on sigma-holes and to provide general trends in organic drug-like molecules. The results are in fair agreement with crystallographic surveys of small molecules as well as biomolecular complexes and may help to improve the intuition of chemists when dealing with halogenated compounds.