Structural diversity in thallium chemistry, IV. Further examples of solid state bromothallate(III) derivatives obtained by employing certain classes of alkyl diammonium cations

Six new bromothallate(III)-containing salts with different alkyl diammonium cations have been prepared from bromide containing solutions and studied by single-crystal X-ray crystallographic analyses. The N,N′-diethyl-N,N,N′,N′-tetramethyl-1,2-ethylenediammonium, N-methyl-1,3-propanediammonium, N,N,N′,N′-tetramethyl-1,3-propanediammonium and N,N,N′,N′-tetraethyl-1,2-ethylenediammonium cations yield complexes (I, II, III and IV, respectively) with the [TlBr5]2− anionic stoichiometry. For I and II, both complexes contain the [TlBr5]2− anion. In complex II, this appears as a distorted octahedron with one long Tl⋯Br2′ contact of 3.632(4) Å from an adjacent anion, thus completing the hexacoordination about an otherwise distorted square pyramid. On the other hand, for III and IV, both complexes contain a tetrahedral [TlBr4]− anion together with an isolated, but hydrogen-bonded, Br− anion. The 1,5-hexanediammonium complex (V) contains tetrahedral [TlBr4]−, slightly distorted octahedral [TlBr6]3− and Br− anions. The asymmetric unit of the N,N-diethyl-1,3-propanediammonium salt (VI) contains one cation and half of each of a [TlBr4]− and an axially compressed octahedral [TlBr6]3− anion. Extensive hydrogen-bonded networks exist in complexes II–VI. NH⋯Br hydrogen bonds generally have a significant influence on the nature of the anions present in species with the formal [TlBr5] stoichiometry.