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

Acta Crystallogr E Crystallogr Commun. 2024 Apr 23;80(Pt 5):506-521. doi: 10.1107/S2056989024002780. eCollection 2024 Apr 1.

Abstract

The structures of fourteen halochalcogenyl-phospho-nium tetra-halogen-ido-aurates(III), phosphane chalcogenide derivatives with general formula [R 1 3- nR 2 nPEX][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, XX contacts (mostly very short) are observed between the cation and anion, whereby the E-XX groups are approximately linear and the XX-Au angles approximately 90°. The exceptions are 17 a, 19 a and 23 a, which instead display short EX 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 EX, XX (some between anions alone), H⋯X and H⋯Au contacts. Even for isotypic compounds, some significant differences can be discerned.

Keywords: crystal structure; gold; halochalcogenyl­phospho­nium; secondary inter­actions.