Secondary bonding. Part 14. Structural isomerism in diaryliodonium halides and the structure of di(p-tolyl)iodonium bromide

Abstract

The X-ray structure of di(p-tolyl) iodonium bromide has been determined from diffractometer data [3 689 observed reflections, I 3.0σ(I)] and refined to R= 0.068. The unit cell contains one centrosymmetric dimer (R₂IBr)₂ and one tetramer (R₂IBr)₄(R =p-tolyl). The dimer corresponds to that found in (Ph₂IBr)₂ but the tetramer is novel. Both contain R₂I⁺ groups linked by secondary bonds to Br^– ions. The I–C bonds [av. 2.124(8)Å] are significantly longer than those in (Ph₂IBr)₂, but the majority of the I ⋯ Br bonds are shorter [range 3.163(2)–3.513(3)Å].