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Reaction of carbonyl trinuclear clusters with 2,5-bis(2-thienyl)-1-phenyl-phosphole as a ligand: A new pathway to ruthenacyclopentadiene and cyclopentadienone ruthenium complexes

Abstract:

[Ru3(CO)12] reacts with 2,5-bis(2-thienyl)-1-phenyl-phosphole (btpp) in refluxing CH2Cl2 to afford mono-, di- and trisubstituted derivatives: [Ru3(CO)11(btpp)] (1), [Ru3(CO)10(btpp)2] (2) and [Ru3(CO)9(btpp)3] (3), as well as the unique ruthenacyclopentadiene compound [Ru2(CO)4(μ-CO)(btpp)(μ-η1:η1:η4-C16H14S2)] (4), whose structure was confirmed by single-crystal X-ray crystallography. The photolysis of 3 in CH2Cl2 leads to the novel complex [Ru(CO)2(btpp)(η4-COC16H14S2)] (5), such that its single-crystal structure reveals the fragmentation of the triruthenium cluster, leading to a cyclopentadienone ruthenium complex. The synthesis of both ruthenacyclopentadiene (4) and cyclopentadienone (5) ruthenium complexes opens access to inaccessible ligand systems with π-conjugated structures that might be interesting in the development of new organometallic materials. The reaction of [Os3(CO)10(CH3CN)2] with btpp in refluxing CH2Cl2 affords mono- and disubstituted clusters: [Os3(CO)11(btpp)] (6) and [Os3(CO)10(btpp)2] (7). The trisubstituted complex [Os3(CO)9(btpp)3] (8) is formed by reaction of compound 7 with equimolar amounts of trimethylamine oxide and btpp. In contrast to 3, no fragmentation product was detected from the triosmium carbonyl cluster [Os3(CO)9(btpp)3] (8). A comparative analysis of the UV-vis spectra of [Ru3(CO)9(btpp)3] (3) and [Os3(CO)9(btpp)3] (8) suggests that their different photochemical reactivities might not only be affected by the energetics of their electronic transitions, but also by a combination of subsequent metal-ligand and metal-metal intramolecular interactions.