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High versatility of 3,4-dimethyl-1-phenyl-phosphole and 3-methyl-1-phenyl-phosphole as ligands in the reaction with [Re 2(CO)8(CH3CN)2] and [Ru3(CO)12]: X-ray structures of [Re2(CO)7(1:2:2-PhPC 4H2Me2)], [Re2(CO)7(1:2:2-PhPC4H3Me)] and [Ru2(CO)4(PhPC 4H3Me)2]

Abstract:

The reaction of [Re<inf>2</inf>(CO)<inf>8</inf>(CH<inf>3</inf>CN) <inf>2</inf>] with 3,4-dimethyl-1-phenylphosphole affords three chromatographically inseparable isomers of [Re<inf>2</inf>(CO) <inf>8</inf>(PhPC<inf>4</inf>H<inf>2</inf>Me<inf>2</inf>)<inf>2</inf>] (1) identified by means of spectroscopic methods, in which the phosphole ligand acts as a tertiary phosphine bonded through the phosphorus atom, and the σ-π complex [Re<inf>2</inf>(CO)<inf>7</inf>(1: 2:2-PhPC<inf>4</inf>H<inf>2</inf>Me <inf>2</inf>)] (2) obtained in low yields. Thermolysis of the mixture of isomers gives (2) in good yields, while photolysis in dichloromethane at room temperature causes metal-metal bond cleavage to give [Re(CO) <inf>4</inf>(PhPC<inf>4</inf>H<inf>2</inf>Me<inf>2</inf>)Cl] (3) and [Re(CO)<inf>5</inf>Cl] (4). The reaction with 3-methyl-1-phenyl-phosphole gives only the σ-π complex [Re<inf>2</inf>(CO)<inf>7</inf>(1: 2:2-PhPC<inf>4</inf>H<inf>3</inf>Me)] (5). Furthermore, the main product of the reaction of [Ru<inf>3</inf>(CO) <inf>12</inf>] with 3-methyl-1-phenyl-phosphole was [Ru<inf>2</inf>(CO) <inf>4</inf>(PhPC<inf>4</inf>H<inf>3</inf>Me)<inf>2</inf>] (6) a sandwich type complex without metal-metal bond. © 2013 Elsevier B.V.