A Series of Homoleptic Linear Trimethylsilylchalcogenido Cuprates, Argentates and Aurates Cat[Me3SiE-M-ESiMe3] (M = Cu, Ag, Au; E = S, Se).

The syntheses and XRD molecular structures of a complete series of silylsulfido metalates Cat[M(SSiMe3)2] (M = Cu, Ag, Au) and corresponding silylselenido metalates Cat[M(SeSiMe3)2] (M = Cu, Ag, Au) comprising lattice stabilizing organic cations (Cat = Ph4P+ or PPN+) are reported. Much to our surprise these homoleptic cuprates, argentates, and aurates are stable enough to be isolated even in the absence of any strongly binding phosphines or N-heterocyclic carbenes as coligands. Their metal atoms are coordinated by two silylchalcogenido ligands in a linear fashion. The silyl moieties of all anions show an unexpected gauche conformation of the silyl substituents with respect to the central axis Si-[E-M-E]-Si in the solid state. The energetic preference for the gauche conformation is confirmed by quantum chemical calculations and amounts to about 2-6 kJ/mol, thus revealing a rather shallow potential mainly depending on electronic effects of the metal. Furthermore, 2D HMQC methods were applied to detect the otherwise nonobservable NMR shifts of the 29Si and 77Se nuclei of the silylselenido compounds. Preliminary investigations reveal that these thermally and protolytically labile chalcogenido metalates are valuable precursors for the precipitation of binary coinage metal chalcogenide nanoparticles from organic solution and for coinage metal cluster syntheses.