Half-sandwich ruthenium complexes of a P–O bifunctional ligand. X-Ray crystal structure of [Ru(η-C5Me5)(OC6H4PPh2){PPh2(C6H4OH)}]
Abstract
The reaction of the phosphine PPh2(C6H4OH) with a reduced solution of [{Ru(η-C5Me5)Cl2}n](1) by zinc in methanol produces [Ru(η-C5Me5)(OC6H4PPh2){PPh2(C6H4OH)}](4). This complex crystallizes in the monoclinic system, space group P21/c, with a= 11.070(1), b= 18.582(2), c= 19.393(2)Å, and β= 106.05(1)° and was refined to R= 0.028 with 4 383 reflections having (Fo2) > 3σ(Fo2). The X-ray structure shows the compound to exhibit strong hydrogen bonding between the hydroxyl proton of the phosphine and the oxygen group of the chelating phenoxy diphenylphosphine ligand [O ⋯ O 2.534(3), O–H 0.97(3), and H ⋯ O 1.57(3)Å]. Compound (4) is unreactive towards H2, NaBH4, LiBHEt3, CF3CO2H, and MeI probably because of electronic and co-ordinative saturation. Reaction of the hydroxyphosphine with [{Ru(η-C5Me5)Cl}4] followed by addition of NEt3 leads to an insoluble solid (5) of the same composition as (4) but proposed to be oligomeric. Compound (5) is again unreactive except with HBF4·Et2O in the presence of which it decomposes. Reaction of PPh2(C6H4OSiMe3) with a reduced solution of (1) in methanol affords [Ru(η-C5Me5)(OC6H4PPh2){PPh2(C6H4OSiMe3)}](6) whereas addition of PPh2(C6H4OH) to (1) followed by reduction with NaBH4 in ethanol affords the trihydride [Ru(η-C5Me5)H3{PPh2(C6H4OH)}](8).