552824-75-6Relevant academic research and scientific papers
Ligand displacement reaction of Ru(η4-1,5-COD)(η6-1,3,5-COT) with Lewis bases
Hirano, Masafumi,Asakawa, Rie,Nagata, Chifumi,Miyasaka, Takashi,Komine, Nobuyuki,Komiya, Sanshiro
, p. 2378 - 2386 (2008/10/08)
Reactions of Ru(η4-1,5-COD)(η6-1,3,5-COT) (1) (COD = cyclooctadiene, C8H12; COT = cyclooctatriene, C8H10) with a series of Lewis bases are studied. Treatments of 1 with P(OMe)3, P(OEt)3, P(OMe)2Ph, P(OEt)2Ph, P(OiPr)3, P(OMe)Ph2, or P(OEt)Ph2 lead to the formation of Ru(η4-1,5-COD)(η4-1,3,5-COT)L (2) followed by preferential liberation of the 1,5-COD ligand to give COT complexes formulated as Ru(6-η1:1-3-η3-COT)L3 (3) and Ru(η4-1,3,5-COT)L3 (4). Reaction of 1 with P(OPh)3 also gives 2, but further treatment of this system leads to the liberation of both 1,5-COD and 1,3,5-COT to give a mixture of Ru(η4-1,5-COD)L3 (5) and Ru(6-η1:1-3-η3-COT)L3 (3) and finally gives Ru{P(OC6H4)(OPh)2}2- {P(OPh)3}2 (6h). In the reaction of 1 with tert-butylisonitrile, 1,3,5-COT is initially liberated with concomitant formation of Ru(η4-1,5-COD)(CNtBu)3 (5j), which further reacts with the liberated 1,3,5-COT, giving eventually Ru(6-η1:1-3-η3-COT)(CNtBu)3 (3j). The molecular structure of 5j determined by X-ray structure analysis reveals that one of the isonitrile ligands has a considerable carbene character. In the presence of excess isonitrile, the homoleptic complex Ru(CNtBu)5 (7) is formed. On the other hand, 1 does not react with poor π-accepting ligands such as NEt3, pyridine, and (dimethylamino)pyridine as well as bulky phosphorus ligands such as triphenylphosphine and tricyclohexylphosphine. These results suggest that the initial coordination of electron-donating ligands to Ru essentially encourages the dissociation of the 1,5-COD ligand, but the π-accepting ability of the ligand induces the dissociation of the 1,3,5-COT ligand.
