Low-melting molecular complexes: Part VII. 2,3-, 2,5- and 3,4-hexanediones and their molecular complexes with chloroform

Crystals of three isomeric 2,3-, 2,5- and 3,4-hexanediones 1–3 and of molecular complexes (1:2) of 2 and 3 with chloroform (4 and 5) were grown by in situ cryocrystallisation and characterised by single-crystal X-ray crystallography. The intermolecular interactions and packing motifs were examined using the analysis of pairwise energies of intermolecular interactions. The method has revealed the importance of carbonyl…carbonyl interactions in the structures 1, 3 and 4 and the relatively weaker halogen bonds in the structures 4 and 5.