A Gold(I)–Acetylene Complex Synthesised using Single‐Crystal Reactivity

Using single‐crystal to single‐crystal solid/gas reactivity the gold(I) acetylene complex [Au( L1 )(η 2 ‐HC≡CH)][BAr F 4 ] is cleanly synthesized by addition of acetylene gas to single crystals of [Au( L1 )(CO)][BAr F 4 ] [ L1 =tris‐2‐(4,4′‐di‐tert‐butylbiphenyl)phosphine, Ar F =3,5‐(CF 3 ) 2 C 6 H 3 ]. This simplest gold‐alkyne complex has been characterized by single crystal X‐ray diffraction, solution and solid‐state NMR spectroscopy and periodic DFT. Bonding of HC≡CH with [Au( L1 )] + comprises both σ‐donation and π‐backdonation with additional dispersion interactions within the cavity‐shaped phosphine.