Crystal structures of fourteen halochalcogenylphosphonium tetrahalogenidoaurates(III)

Abstract

The structures of fourteen halochalcogenylphosphonium tetrahalogenidoaurates(III), phosphane chalcogenide derivatives with general formula [R 1 3– nR 2 n PEX][AuX 4] (R 1 = t-butyl; R 2 = isopropyl; n = 0 to 3; E = S or Se; X = Cl or Br) are presented. The eight possible chlorido derivatives are: 17 a , n = 3, E = S; 18 a , n = 2, E = S; 19 a , n = 1, E = S; 20 a , n = 0, E = S; 21 a , n = 3, E = Se; 22 a , n = 2, E = Se; 23 a , n = 1, E = Se; and 24 a , n = 0, E = Se, and the corresponding bromido derivatives are 17 b –24 b in the same order. Structures were obtained for all compounds except for the tri-t-butyl derivatives 24 a and 24 b . Isotypy is observed for 18 a /18 b /22 a /22 b , 19 a /23 a , 17 b /21 b and 19 b /23 b . In eleven of the compounds, X...X contacts (mostly very short) are observed between the cation and anion, whereby the E—X...X groups are approximately linear and the X...X—Au angles approximately 90°. The exceptions are 17 a , 19 a and 23 a , which instead display short E...X contacts. Bond lengths in the cations correspond to single bonds P—E and E—X. For each group with constant E and X, the P—E—X bond-angle values increase monotonically with the steric bulk of the alkyl groups. The packing is analysed in terms of E...X, X...X (some between anions alone), H...X and H...Au contacts. Even for isotypic compounds, some significant differences can be discerned.