Tris(dimethylphenylphosphine)ruthenium(0) complexes of η⁴-coordinated polycyclic aromatic hydrocarbons

From the reaction of [Ru₂Cl₃(PMe₂Ph)₆] Cl with the appropriate radical anions, yellow complexes of general formula [Ru(PMe₂Ph)₃(η₄-arene)] [arene = naphthalene (C₁₀H₈) (1), anthracene (C₁₄H₁₀) (2), and triphenylene (C₁₈H₁₂) (3)] have been isolated in poor yield and characterized by elemental analysis, n.m.r. (¹H, ¹³C, ³¹P) spectroscopy and single-crystal X-ray diffraction. Crystal data: (1), monoclinic, C 2/c, a 31.096(8), b 12.012(4), c 17.078(8) Å, β 104.41(3)°, V 6178(4) ų, Z 8, refined to final R value of 0.032 with use of 3641 reflections [I>3σ(I)]; (2), monoclinic, C 2/c,a 55.909(4), b 14.348(5), c 17.573(5) Å, β 105.41(1)°, V 13590(6) ų,Z 16 (two molecules per asymmetric unit), refined to final R value of 0.049 with use of 7770 reflections [I> 3σ(I)]; (3), monoclinic, Pn, a 9.377(3), b 12.229(3), c 15.975(3) Å, β103.51(2)°, V 1781.2 (7) ų, Z 2, refined to final R value of 0.026 with use of 2830 reflections [I > 3σ(I)]. In each case, coordination of the zerovalent metal fragment Ru(PMe₂Ph)₃ to the diene section of one of the terminal rings causes the aromatic molecule to be folded by c. 40° at the outer carbon atoms of the diene. The coordination geometry about ruthenium is approximately square pyramidal, with the diene and two tertiary phosphines in the equatorial plane and the remaining tertiary phosphine in the axial site.