Hydrogen Bonding versus Halogen Bonding in Host–Guest Compounds

The similarity and differences of the three host compounds <b>H1</b> = 9,9′-(biphenyl-2,2′-diyl)­difluoren-9-ol, <b>H2</b> = 2,2′,7,7′-tetrabromo-9,9′-(biphenyl-2,2′-diyl)­difluoren-9-ol, and <b>H3</b> = 2,2′,7,7′-tetra-<i>tert</i>-butyl-9,9′-(1,4-phenylene)­difluoren-9-ol which form inclusion compounds with 3-bromopyridine and its chloro-analogue guest are compared with respect to hydrogen bonding and halogen bonding. In all cases the hydrogen bonding motif (Host)­O–H···O­(Host)–H···N­(Guest) predominates while the halogen···halogen interactions are of secondary importance in the packing of the structures. The structural data are supported by thermal analysis, Hirshfeld surface analysis, and IR spectroscopy