Interplay of Hydrogen and Halogen Bonding in the Crystal Structures of 2,6-Dihalogenated Phenols

Abstract

Hydrogen and halogen bonds are important anisotropic attractive interactions in the molecular crystalline state. 2,6-dibromophenol (1) was analyzed by single-crystal X-ray diffraction for the first time. The intermolecular interaction pattern was studied by Hirshfeld surface analysis along with 2D fingerprint diagrams. The characteristic interactions that dominate the crystal packing are electrostatic type-II Br⋅⋅⋅Br interactions, O−H⋅⋅⋅O hydrogen bonds, and an offset parallel π-stacking arrangement. Compound 1 was compared with 2,6-difluoro- (2) and 2-bromo-6-chlorophenol (3) in terms of their interplay between hydrogen and halogen bonding. Whereas the O−H⋅⋅⋅O hydrogen bond is more pronounced in the lighter homologues, the halogen⋅⋅⋅halogen interaction becomes a particularly important directional, attractive interaction in the crystal structure of 2,6-dibromophenol.