Generation of a high symmetry 2D-polybromide network in the structure of {[(o-SCH3C6H4)3PBr][Br]•0.5(μ-Br2)3}n. The templating effect of the C3 symmetric [(o-SCH3C6H4)3PBr]+ cation

The reaction of (o-SCH3C6H4)(3)P with three equivalents of dibromine produces the unusual salt {[(o-SCH3C6H4)(3)PBr][Br]center dot 0.5(mu-Br-2)(3)}(n), which contains a bromo-phosphonium cation and a polybromide network built up of [Br](-) anions and dibromine molecules. This structure is the first reported compound with an R3PBr5 stoichiometry, and exhibits a network structure, which propagates via bromide anions interacting with three different dibromine molecules, {((Br)(-)(mu-Br-2)(3)}(n). Each bromide anion also interacts with one [(o-SCH3C6H4)(3)PBr](+) cation. The two-dimensional polybromide network that is formed is templated around the [(o-SCH3C6H4)(3)PBr](+) cation, with both the cation and the polybromide network exhibiting crystallographically imposed C-3 symmetry. The crystal packing allows [(o-SCH3C6H4)(3)PBr](+) cations to pack in a back-to-back fashion, with formation of an (EF)(6) aryl embrace. This type of commonly observed aryl embracing motif is possible as the (o-SCH3C6H4) rings adopt an exo(3) conformation. The polybromide network is arranged around the cations, and forms 18-membered hexagonal rings (consisting of six bromide anions and six dibromine molecules), and the rings adopt a chair conformation. The structure and connectivity of the network is discussed and compared with other known polybromide species. (C) 2013 Elsevier Ltd. All rights reserved.