Reaction of mercury (II) dibromide with tris(n-butyl) phosphine telluride: Formation of an unusual (Hg Te)3 ring system

Tris(n-butyl)phosphine telluride (R₃PTe) yields, with HgBr₂ from acetone solution, a very thermally and air sensitive crystalline solid. This solid has been identified as (HgBr₂)₄ · (TePR₃)₃. X-ray diffraction analysis reveals that this compound contains a dimeric cation, [(HgTePR₃)₃Br₅]²⁻₂, in which each unit is characterized by a six-membered ring made of alternating bonds between mercury and tellurium. The counter ion is a di-nuclear anion [Hg₂Br₀]²⁻. The crystal belongs to the triclinic system, P1 group with a = 12.206(9) A, b = 17.613(10) A, c = 18.065(9) A, and Z = 2. The preparation of this new heterocyclic system and its decomposition under different conditions into Hg₃Te₂Br₂ or HgTe are presented. © 1996 John Wiley & Sons, Inc.