Cyclopentadienyl-ruthenium and -osmium chemistry: XXIV. Some complexes containing the olefinic tertiary phosphine 2-CH2CHC6H4PPh2 (sp): X-ray structures of one isomer of OsBr(sp)(η-C5H5), and of Ru(η3-S2CCHMeC6H4PPh2-2)(η-C5H5), containing an η3-dithiocarboxylato group

Reactions between MX(PPh₃)₂(η-C₅H₅) (M = Ru, X = Cl; M = Os, X = Br) and 2-CH₂CHC₆H₄PPh₂ afford $\text{MX(η}{}^2\text{-CH}{}_2\text{CHC}{}_6\text{H}{}_4\text{P}$Ph₂)(η-C₅H₅); the Os complex is obtained in two isomeric forms. The X-ray structure of the major isomer shows the CC double bond (OsC, 2.214, 2.195 Å; CC, 1.57 Å) is almost coplanar with the OsBr vector, with the terminal C cis to Br; the minor isomer is assumed to have the alternative, more sterically congested conformation, with the β-C cis to Br. The chlororuthenium complex reacts with NaOMe/MeOH to give the corresponding hydrido complex, which also exists as two isomers in solution; reaction of this complex with CS₂ gives the expected dithio acid derivative $\text{Ru(S}{}_2\text{CCHMeC}{}_6\text{H}{}_4\text{P}$Ph₂)(η-C₅H₅), together with small amounts of a complex assumed to be $\text{RuS}{}_2\text{C(CH}{}_2\text{)}{}_2\text{C}{}_6\text{H}{}_4\text{P}$Ph₂](η-C₅H₅). The X-ray structure of the major product reveals an unusual η³-S₂C mode of coordination of the dithio acid fragment (RuS, 2.418, 2.426(1) Å; RuC 2.175(4) Å). Crystals of OsBr(η²-CH₂CHC₆H₄P)Ph₂)( η-C₅H₅) are monoclinic, space group P2₁/n, with a 12.696(2), b 21.719(6), c 15.929(3) Å, β 79.77(2)°, Z = 8; 2867 data (I > 2.5σ(I)) were refined to R = 0.040, R_w = 0.044. Crystals of $\text{Ru(η}{}^3\text{-S}{}_2\text{CCHMeC}{}_6\text{H}{}_4\text{P}$Ph₂)(η-C₅H₅) are orthorhombic, space group Pbca, with a 8.921(2), b 15.982(9), c 32.216(5) Å, Z = 8; 1685 data (I > 2.5σ(I)) were refined to R = 0.027, R_w = 0.030.