Cyclopentadienyl-ruthenium and -osmium chemistry. XXIX. The effect of chelation on Ru-C(sp²) bond lengths: X-ray structures of Ru(C₆H₄PPh₂)(PPh₃)(η-C₅H₅)-·0.5CH₂Cl₂ and Ru{C(CMePh)CH(PPh₂)CH₂PPh₂}-(η-C₅H₅)

The molecular structures Ru(C₆H₄PPh₂)(PPh₃)(η-C₅H₅) (1) and Ru{C(CMe-Ph)CH(PPh₂)CH₂PPh₂}(η-C₅H₅) (2) have been determined. In 1, strain about the RuPCC chelate ring is accommodated largely by contraction of the intra-ring angles about the relevant atoms. In 2 there are similar contractions, together with marked lengthening of the Ru-C(sp²) bond (to 2.149(5) Å) and of the CC bond (1.534(7) Å) from the vinyl α-carbon to the CHPPh₂ group of the chelating tertiary phosphine; the latter bond is 0.11 Å shorter than that in the iron analogue. Crystal data: 1 (as 0.5CH₂Cl₂ solvate): triclinic, space group P1, a 8.409(2), b 19.055(5), c 21.921(9) Å, α 94.10(3), β 97.02(2), γ 99.92(2)°, U 3418.6 ų, Z = 4; 2007 data (I ≥ 2.5σ(I)) were refined to R = 0.047, R_w = 0.051; 2: triclinic, space group P1,a 12.141(1), b 14.004(1), c 11.333(1) Å, α 112.19(1), β 101.15(1), γ 69.01(1)°, U 1662.0 ų, Z = 2, 3788 data (I ≥ 2.5σ(I)) were refined to R = 0.047, R_w = 0.050.