The syntheses, structures and redox properties of phosphine-gold(I) and triruthenium-carbonyl cluster derivatives of tolans

The syntheses of several ethynyl-gold(I)phosphine substituted tolans (1,2-diaryl acetylenes) of general form [Au(CCC₆H₄CCC₆H₄X)(PPh₃)] are described [X = Me (2a), OMe (2b), CO₂Me (2c), NO₂ (2d), CN (2e)]. These complexes react readily with [Ru₃(CO)₁₀(μ-dppm)] to give the heterometallic clusters [Ru₃(μ-AuPPh₃)(μ-η¹,η²-C₂C₆H₄CCC₆H₄X)(CO)₇(μ-dppm)] (3a-e). The crystallographically determined molecular structures of 2b, 2d, 2e and 3a-e are reported here, that of 2a having been described on a previous occasion. Structural, spectroscopic and electrochemical studies were conducted and have revealed little electronic interaction between the remote substituent and the organometallic end-caps.