The C–I⋯O halogen bonding in crown ether chemistry

Abstract

The role of the C–I⋯O halogen bonding in crown ether chemistry has been analyzed and rationalized by using thirteen newly synthesized cocrystals as models. The monotopic C–I⋯O halogen bonding was found to play a dominant role, whereas the bifurcated halogen bonding and the hydrogen-bond enhanced halogen bonding play minor roles. An unexpected new finding is that some binary mixtures of halogen-bond donor and acceptor can spontaneously absorb trace amounts of water from the solvent during the crystal growth period, forming more complex ternary cocrystals.