Influence of Halogen Bonding Interactions in Crystalline Networks of Tetraarylethylene Halobenzoyl Esters

Solid state halogen bonding interactions have been examined in structurally similar tetratopic haloarenes bearing a common tetraphenylethylene core. This study was designed with the aim of providing insight into the relative importance of fundamental solid state halogen bonding interactions (i.e., halogen center dot center dot center dot halogen, halogen center dot center dot center dot pi, and halogen... carbonyl) in systems devoid of strong hydrogen bonding groups. The substrates used in this study all featured four halobenzoate substituents (halogen = Br or I) attached to the four para positions of tetraphenylethylene with conformationally flexible ester linkages. A total of nine crystal structures from five different tetraarylethylene substrates were obtained. While distinct and unique X center dot center dot center dot O and X center dot center dot center dot pi halogen bonding interactions were identified in each structure, all structures displayed nominally similar packing arrangements generally consisting of one-dimensional ribbons aligned to generate non-interpenetrating twodimensional sheets. This feature may be a consequence of extensive edge-to-face arene arene interactions found in each structure and may indicate a greater structure-determining role for aryl-H center dot center dot center dot pi interactions relative to halogen bonding contacts in this system.