Silylimido and Disilylamido Groups as Clustering Centers for (Phosphane)gold(I) Units: Aurated Silylammonium Cations

The reaction of hexamethyldisilazane with tris[(phosphane)‐aurio(I)]oxonium tetrafluoroborates affords the corresponding trinuclear μ₃‐trimethylsilylimido compounds of the type {[(R₃P)Au]₃NSiMe₃}⁺ BF₋₄ (1a‐f). With (triphenylsilyl)amine and the oxonium reagents the analogous series of Ph₃Si derivatives (2a‐f) is formed (R = Me, Et, iPr; R₃ = Ph2Me; R = Ph, o‐Tol). The Et₃P‐based oxonium salt and (Me₃Si)₂NH give the dinuclear μ‐trimethylsilylamido complex {[(Et₃P)Au]₂N(SiMe₃)₂)₂}⁺ BF₋₄ (3) as the main product. The crystal and molecular structures of complexes 2a, 2e, and 3 were determined. The trinuclear cations have a pseudo‐tetrahedral structure with small Au‐N‐Au angles and short Au‐Au distances for the SiNAu₃ units. The Ph₃SiN units in 2a and 2e are capping triangles of gold atoms, while in the cation of 3 the (Me₃Si)₂N unit is bridging a pair of gold atoms. In the ³¹P‐ and ¹⁴N‐NMR spectra of compounds 1 and 2 (except for 1f and 21) the coupling J(³¹P,¹⁴N) is observed. This coupling is temperature‐dependent, owing to changes in the relaxation characteristics in solution at low temperature. The decomposition of compounds 1 and 2 leads to the formation of pentanudear dications {[(R₃P)Au]₅N}²⁺ for R = Me, Ph.