Reactions of Ruthenium(II)-co-ordinated Phenyl Phosphines: Synthesis and X-Ray Crystal Structures of the Orthometallated Complexes [Ru(C6H4PR1R2)(CH2SiMe3)(eta-6-C6Me6)] (R1=R2=Ph; R1=Ph, R2=Me; R1=R2=Me) and of [{Ru(CH2SiMe3)2(mu-sigma,eta-6-PMe2Ph)}2] containing Bridging Dimethylphenylphosphine Ligands

Title full: Reactions of ruthenium(II)-co-ordinated phenyl phosphines: Synthesis and X-ray crystal structures of the orthometallated complexes [Ru(C6H4PR1R2)(CH 2SiMe3)(η6-C6Me 6)](R1 = R2 = Ph; R1 = Ph, R2 = Me; R1 = R2 = Me) and of [{Ru(CH2SiMe3)2(μ-σ,η 6-PMe2Ph)}2] containing bridging dimethylphenylphosphine ligands. The compounds [RuCl2(η6-C6Me6)L] [L = PPh3, (1); PMePh2, (2); or PMe2Ph, (3)] react with an excess of Mg(CH2SiMe3)Cl to give the corresponding orthometallated complexes [Ru(C6H4PR1R1R2)(CH 2SiMe3)(η6-C6Me6)] [R1 = R2 = Ph, (4); R1 = Ph, R2 = Me, (5); R1 = R2 = Me, (6)]. Both diastereomers of (5) have been isolated in a pure form. In the alkylation of (3) the dimeric dialkyl derivative [{Ru(CH2SiMe3)2(μ-σ, η6-PMe2Ph)}2] (7) and the chloroalkyl compound [RuCl(CH2SiMe3)(η6-C6Me 6) (PMe2Ph)] (8) have also been isolated. The X-ray crystal structures of complexes (4)-(7) have been determined. Crystal data are: (4), a = 10.622(3), b = 15.851(10), c = 18.963(18) Å, β = 103.64(2)°, Z = 4, space group P21/c, R (2 202 reflections, 506 parameters) = 0.0599; (5a), a = 12.215(8), b = 17.920(10), c = 13.023(7) Å, β = 100.02(2)°, Z = 4, space group P21/a, R (4 505, 453) = 0.0528; (5b), a = 11.457(6), b = 11.452(5), c = 10.736(5) Å, α = 91.96(1), β = 96.39(1), γ = 87.92(1)°, Z = 2, space group P1, R (5 855, 453) = 0.0435; (6), a = 14.633(4), b = 14.527(4), c = 11.936(3) Å, α = 94.03(1), β = 91.54(1), γ = 77.78(1)°, Z = 4, space group P1, R (5 763, 244) = 0.0393; (7), a = 15.966(2), b = 13.165(1), c = 21.213(5) Å, β = 109.94(1), Z = 8, space group C2/c, R (2 899, 191) = 0.0593. The molecular structures of (4)-(6) are of the 'three-legged piano-stool' type, where the bulky C6Me6 ligand (effective cone angle 157-160°) produces widenings of the other co-ordination polyhedron angles. The orthometallated ring is planar and practically coplanar with the benzene ring that shows significant deformations in the angles at the carbon atoms involved in the cyclometallation. The molecular structure of complex (7) is binuclear with a centrosymmetric six-membered ring having a chair conformation. The formation of the orthometallated compounds is discussed.