Homoleptic Phosphaalkyne Complexes of Silver(I).

By employing silver salts with a weakly coordinating anion Ag[A] ([A]=[FAl{OC12 F15 }3 ], [Al{OC(CF3 )3 }4 ]), two phosphaalkynes could be coordinated side-on to a bare silver(I) center to form the unprecedented homoleptic complexes [Ag(η2 -P≡CtBu)2 ][FAl{OC12 F15 }3 ] (1) and [Ag(η2 -P≡CtBu)2 ][Al{OC(CF3 )3 }4 ] (2). DFT calculations show that the perpendicular arrangement in 1 is the minimum energy structure of the coordination of the two phosphaalkynes to a silver atom, whereas for 2 a unique square-planar coordination mode of the phosphaalkynes at Ag+ was found. Reactions with donor molecules yield the trigonally planar coordinated silver salts [((CH3 )2 CO)Ag(η2 -P≡CtBu)2 ][FAl{OC12 F15 }3 ] (3) and [(C7 H8 )2 Ag(η2 -P≡CtBu)][FAl{OC12 F15 }3 ] (4). All of the compounds were comprehensively characterized in solution and in the solid state.