99094-58-3Relevant academic research and scientific papers
Selective diphosphine ligand chelation and π bond coordination in CoRu(CO)7(μ-PPh2): Kinetics and X-ray structure of CoRu(CO)4(μ-bma)(μ-PPh2)
Bott,Yang,Wang,Richmond
, p. 6051 - 6055 (2008/10/08)
Thermolysis of CoRu(CO)7(μ-PPh2) (1) in refluxing 1,2-dichloroethane in the presence of the diphosphine ligands 2,3-bis(diphenylphosphino)maleic anhydride (bma) and 4,5-bis(diphenylphosphino)-4-cyclopenten-1,3-dione (bpcd) furnishes the new mixed-metal complexes CoRu(CO)4(μ-P-P)(μ-PPh2) [where P-P = bma (3a), bpcd (3b)] along with trace amounts of the known complex CoRu(CO)6(PPh3)(μ-PPh2) (4). The requisite pentacarbonyl intermediates CoRu(CO)5(μ-P-P)(μ-PPh2)[where P-P = bma (2a), bpcd (2b)] have been prepared by separate routes (mild thermolysis and Me3NO activation) and studied for their conversion to CoRu(CO)4(μ-P-P)(μ-PPh2). The penta- and tetracarbonyl complexes have been isolated and fully characterized in solution by IR and NMR spectroscopy. The kinetics for the conversion of 2a → 3a and of 2b → 3b were measured by IR spectroscopy in chlorobenzene solvent. On the basis of the first-order rate constants, CO inhibition, and the activation parameters (2a → 3a, ΔH? = 29.2 ± 1.4 kcal mol-1 and ΔS? = 8.2 ± 3.8 eu; 2b → 3b, ΔH? = 27.7 ± 0.6 kcal mol-1 and ΔS? = 1.4 ± 1.6 eu), a mechanism involving dissociative CO loss as the rate-limiting step is proposed. The solid-state structure of CoRu(CO)4(μ-bma)(μ-PPh2) (3a), as determined by X-ray crystallography, reveals that the two PPh2 groups are bound to the ruthenium center while the maleic anhydride π bond is coordinated to the cobalt atom.
Site selectivity in substitution reactions of heterobinuclear (CO)4Ru(μ-PPh2)Co(CO)3(Ru-Co): Synthesis and characterization of terminal anionic hydrido and halo complexes [Et4N][(X)(CO)3Ru(μ-PPh2)Co(CO) 3]. X-ray structure of [Et4N][(H)(CO)3Ru(μ-PPh2)Co(CO)3]
Guesmi, Salaheddine,Dixneuf, Pierre H.,Süss-Fink, Georg,Taylor, Nicholas J.,Carty, Arthur J.
, p. 307 - 313 (2008/10/08)
The synthesis and characterization of a series of heterobinuclear phosphido-bridged anionic complexes, [M][(X)(CO)3Ru(μ-PPh2)Co(CO)3] (M = Et4N, X = H, 2; M = [(Ph3P)2N], X = I, 3a; M = [(Ph3P)2N], X = Br, 3b), are described. These products result from site-specific substitution of a carbonyl group on the ruthenium atom of (CO)4Ru(μ-PPh2)Co(CO)3 (1) by a hydride or halide ion at the axial-cis and equatorial-trans positions, respectively. The molecular structure of [Et4N][(H)(CO)3Ru(μ-PPh2)Co(CO)3] (2) has been determined by X-ray diffraction. Crystal data: RuCoPO6NC26H31, monoclinic crystals, space group Cc with a = 8.185 (1) A?, b = 22.621 (3) A?, c = 15.865 (2) A?, β = 98.67 (1)°, and Z = 4. The structure was solved and refined to R and Rw values of 0.035 and 0.043, respectively, by using 2302 observed reflections. In the phosphido-bridged heterobinuclear anion a terminal hydride occupies an axial site on ruthenium trans to a CO group and cis to the phosphide bridge with the latter supporting a strong Ru-Co bond (Ru-Co = 2.737 (1) A?). The reactions of the hydrido anion 2 toward MeI, H+, Ph3P, and Ru3(CO)12 are discussed.
