Coupling reaction between the uncoordinated acetylenic bond of [Ru3(CO)10{μ3-FcC2CCFc}] and FcCCCCFc to form [Ru2(CO)6{C4Fc2(CCFc)2}2], [Ru2(CO)6[μ-η1:η1:η2:η2-{FcCCCC(Fc)–C(O)–C(Fc)CCCFc}] and [Ru2(CO)6[μ-η1:η1: η2:η2-{FcCCCC(Fc)–C(O)–C(–CCFc)C(Fc)}]

Low temperature photolysis of a hexane solution of [Ru3(CO)12] and FcCCCCFc provides a convenient route to the diyne-bridged cluster [Ru3(CO)10{μ3-FcC2CCFc}] (1). When a toluene solution containing 1 and diferrocenyldiacetylene was heated at 80 °C three compounds formed: the ruthenacyclopentadiene complex [Ru2(CO)6{C4Fc2(CCFc)2}2] (2), and two isomers of the diruthenacycloheptadienone complex, [Ru2(CO)6[μ-η1:η1:η2:η2-{FcCCCC(Fc)–C(O)–C(Fc)CCCFc}] (3), [Ru2(CO)6[μ-η1:η1:η2:η2-{FcCCCC(Fc)–C(O)–C(–CCFc)C(Fc)}] (4). Compounds 2–4 have been characterized spectroscopically and their structures established crystallographically. Consistent with structural reports on metallacyclic compounds bearing bulky substituents, in 2 and 3, the bulkier of the two types of substituents, the CCFc groups are located on the carbon atoms adjacent to the metal atoms, whereas in compound 4, only one of the two CCFc groups is on the α-carbon atom of the ruthenacyclopentadienone ring.

Graphical abstractA coupling reaction between the uncoordinated acetylenic bond of [Ru3(CO)10{μ3-FcC2CCFc}] (1) and FcCCCCFc occurs to form the ruthenacyclopentadiene complex [Ru2(CO)6{C4Fc2(CCFc)2}2] (2), and two isomers of the diruthenacycloheptadienone complex, [Ru2(CO)6[μ-η1:η1:η2:η2-{FcCCCC(Fc)–C(O)–C(Fc)CCCFc}] (3) and [Ru2(CO)6[μ-η1:η1:η2:η2-{FcCCCC(Fc)–C(O)–C(–CCFc)C(Fc)}] (4).Figure optionsDownload full-size imageDownload as PowerPoint slide