CYCLOPENTADIENYLRUTHENIUM AND CYCLOPENTADIENYLOSMIUM CHEMISTRY .33. CYCLOBUTENYL NITRILE COMPLEXES - X-RAY STRUCTURES OF RU[C=CPHC(CF3)2C(CN)2](NCME)(PPH3)(ETA-C5H5) AND [RU[C=CPHC(CF3)2C(CN)2](PPH3)(ETA-C5H5)]2-[MU-(NC)2C=C(CF3)2]

Replacement of MeCN in Ru[C═CPhC(CF3)2C(CN)2](NCMe)(PPh3)(η-C5H5), readily obtained from the bis-PPh3 complex in MeCN, by a series of organonitrile ligands (CH2═CHCN, trans-CH(CH)═CH(CN), C(CN)2═C(CF3)2 (dcfe), C2(CN)4, o-C6H4(CN)2) p-C6H4(CN)2, o-C6F4(CN)2, p-C6F4(CN)2, C6H2(CN)4) has given highly colored complexes containing one or two Ru[C═CPhC(CF3)2C(CN)2](PPh3)(η-C5H5) moieties. The binuclear complexes are bridged by the di- or tetranitriles; isomers were found for the fumaronitrile, dcfe, and C2(CN)4 derivatives. The deep blue μ-dcfe complexes are readily oxidized to green paramagnetic species that appear to contain an epoxy radical ligand. The complexes were characterized by spectroscopic and electrochemical studies and, in the case of the title complexes, by single-crystal X-ray diffraction studies. Crystals of Ru[C═CPhC(CF3)2C(CN)2](NCMe)(PPh3)(η-C5H5) (4) crystallize in the triclinic space group P1 with unit cell dimensions a = 13.682 (2) Å, b = 15.616 (2) Å, c = 9.776 (4) Å, α = 97.97 (4)°, β = 92.90 (3)°, and γ = 80.53 (2)° with Z = 2. Crystals of [Ru[C═CPhC(CF3)2C(CN)2](PPh3)(η-C5H5)]2[μ-(NC)2C═C(CF3)2] (2a) are monoclinic, space group P21/c, with unit cell parameters a = 20.48 (1) Å, b = 19.378 (4) Å, c = 20.914 (3) Å, β = 112.6 (3)°, and Z = 4. The structures were refined by a full-matrix (blocked-matrix for 2a) least-squares procedure to final R = 0.059 and Rw = 0.064 for 3883 reflections with I ≥ 2.5σ(I) for 4 and R = 0.045 and Rw = 0.045 for 1708 reflections for 2a. © 1990, American Chemical Society. All rights reserved.