Halogen-Bonded Cocrystals of 1,3,5-Triiodo-2,4,6-trifluorobenzene and Structural Isomers of Benzoylpyridine

Six novel halogen-bonded cocrystals of 1,3,5-triiodo-2,4,6-trifluorobenzene with three structural isomers of benzoylpyridine have been synthesized mechanochemically and by crystallization from solution, five of which were structurally characterized. In four cocrystals, benzoylpyridine is a ditopic halogen-bond acceptor participating in halogen bonding with both pyridine nitrogen and carbonyl oxygen atoms, while in one cocrystal, only the I...N halogen bond has formed. In general, the I...N halogen bonds are shorter than I...O interactions, except in the cocrystals with 2-benzoylpyridine. The N and O halogen-bond acceptor sites were evaluated using calculated molecular electrostatic potentials (MEPs) and binding energies of both I...N and I...O halogen-bonded dimers in the gas phase.