Crystal structures of fourteen halochalcogenylphos-pho-nium tetra-halogenidoaurates(III).

The structures of fourteen halochalcogenyl-phospho-nium tetra-halogen-ido-aurates(III), phosphane chalcogenide derivatives with general formula [ R 1 3- n R 2 n P EX ][Au X 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.