Photochemical reactions of 1-ferrocenyl-4-phenyl-1,3-butadiyne with Fe(CO)5 and CO

Photolysis of a hexane solution containing ironpentacarbonyl, 1-ferrocenyl-4-phenyl-1,3-butadiyne at low temperature yields six new products: [Fe(CO)2{η2:η2-PhCtriple bond; length of mdashCCC(Fc)C(Ctriple bond; length of mdashCPh)C(Fc)Fe(CO)3}-μ-CO] (1), [Fe2(CO)6{μ-η1:η1:η2:η2-PhCtriple bond; length of mdashCCC(Fc)–C(O)–C(Fc)CCtriple bond; length of mdashCPh}] (2), [Fe2(CO)6{μ-η1:η1:η2:η2-FcCC(Ctriple bond; length of mdashC Ph)–C(O)–C(Fc)CCtriple bond; length of mdashCPh}] (3), [Fe2(CO)6{μ-η1:η1:η2:η2-FcCtriple bond; length of mdashCCC(Fc)–C(O)–C(Fc)CCtriple bond; length of mdashCPh}] (4), [Fe(CO)3{μ-η2: η2-[FcCC(Ctriple bond; length of mdashCPh)C(Ctriple bond; length of mdashCPh)C(Fc)}CO] (5) and [Fe(CO)3{μ-η2: η2-[FcCC(Ctriple bond; length of mdashCPh)C(Ctriple bond; length of mdashCPh)C(Fc)}CO] (6) formed by coupling of acetylenic moieties with CO insertion on metal carbonyl support. In presence of CO, formation of another new product 2,5-bis(ferrocenyl)-3,6-bis(tetracarbonylphenylmaleoyliron)quinone (7) was observed which on further reaction with ferrocenylacetyene gave the quinone, 2,5-bis(ferrocenyl)-3,6-bis(ethynylphenyl)quinone (8). Structures of 1–5 and 8 were established crystallographically.