Strong coordination of cycloheptynes by gold(i) chloride: synthesis and structure of two complexes of the type [(alkyne)AuCl]

Gold(I) chloride (stabilized by tetrahydrothiophene) reacts with the cycloheptynes 3,3,6,6-tetramethyl-1-thiacyclohept-4-yne-1,1-dioxide (SO2-alkyne) and 3,3,6,6-tetramethyl-1-thiacyclohept-4-yne (S-alkyne) to afford the complexes [(η2-alkyne)AuCl]n [n = 2 (SO2-alkyne), n = ∞ (S-alkyne)]; the X-ray structures of both compounds show trigonal-planar gold(I) centres and very short Au–C(alkyne) bonds.