Effect of ortho- and para-chlorine substitution on hydroxychlorochalcone.

This work describes a comparative molecular structure of two hydroxychlorochalcones with an emphasis on their planarity. Hirshfeld surface analysis investigates the effect of ortho- and para-chlorine substitution on supramolecular arrangement and physical chemical properties. The molecular conformation of 2'-hydroxy-4',6'-dimethyl-2-chlorochalcone and 2'-hydroxy-4',6'-dimethyl-4-chlorochalcone chalcones was obtained through DFT with the exchange-correlation functional M06-2X and the 6-311++G(2d,2p) basis set, and the results were compared with the experimental X-ray data in order to get insights on the effect of ortho- and para-chlorine substitution. The charge transfer into entire main carbon chain was also investigated using frontier molecular orbitals (HOMO and LUMO), NBO, and MEP map in order to describe the comparative conformational stability due to the resonance effect produced by π electron displacements. Finally, the intermolecular observed interactions were analyzed by QTAIM, with the M06-2X/6-311G++(d,p) theory level.