X-Ray Structure Determinations of Bromo- and/or Bromomethyl-substituted Benzenes: C-H center dot center dot center dot Br, C-Br center dot center dot center dot Br, and C-Br center dot center dot center dot pi Interactions

Abstract

Z. Naturforsch. 2012, 67b, 1273-1281 / DOI: 10.5560/ZNB.2012-0249 Received September 18, 2012 Belatedly dedicated to Professor Joachim Heinicke on the occasion of his 65th birthday The structures of seven benzene derivatives [1,2,3-tri(bromomethyl)benzene, (1); 3,5-di(bromomethyl)bromobenzene, (2); 2,5-di(bromomethyl)bromobenzene, (3); 4-(bromomethyl)-2,5-dibromotoluene, (4); 4-(bromomethyl)bromobenzene, (5); 2,3-di(bromomethyl)bromobenzene, (6) and (bromomethyl)-p-dibromobenzene, (7)] with bromo and bromomethyl (and in one case methyl) substituents are presented and analysed in terms of Br center dot center dot center dot Br interactions up to 4.0 angstrom, supported by hydrogen bonds H center dot center dot center dot Br. Some interactions of the type Br center dot center dot center dot pi and pi center dot center dot center dot pi are encountered and play a subordinate role in the packing. Despite the close chemical similarity of the compounds, some of which are isomers with permuted substituent positions, the packing motifs are highly variable. Compounds 2-5 are based on layer structures with Br-n (n = 3, 4) and/or mixed Br/C rings. Compounds 1, 6 and 7 display three-dimensional packings of differing complexity, but with interpretable substructures; 1 can be analysed in terms of ribbons of linked Br-3 and Br-4 rings; 6 displays chains of linked Br-3 triangles; 7 consists of ribbons of linked Br-4 quadrilaterals.