99094-59-4Relevant 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.
Reactivity patterns of heterobinuclear carbonyls: Site selectivity in substitution reactions of (CO)4Ru(μ-PPh2)Co(CO)3 with phosphines and the X-ray structure of (Ph3P)Ru(CO)3(μ-PPh2)Co(CO)3
Regragui, Rachid,Dixneuf, Pierre H.,Taylor, Nicholas J.,Carty, Arthur J.
, p. 1 - 8 (2008/10/08)
The substitution behavior of the phosphido-bridged heterobinuclear carbonyl (CO)4Ru(μ-PPh2)Co(CO)3, 1, toward phosphines L [PPh2H, PMe3, PMe2Ph, PPhMe2, PPh2C≡CR (R = t-Bu, Ph), PPh3] has been investigated. A series of monosubstitution products (L)(CO)3Ru(μ-PPh2)Co(CO)3, 2, and of disubstitution products L2(OC)2Ru(μ-PPh2)Co(CO)3, 3, has been characterized by spectroscopic methods including variable-temperature 31P NMR spectroscopy. The crystal structure of (PPh3)(CO)3Ru(μ-PPh2)Co(CO)3 has been determined. Crystal data: monoclinic space group P21/n, a = 13.669 (2) A?, b = 11.583 (3) A?, c = 20.908 (5) A?, β = 95.72 (2)°, Z = 4. The structure was solved by heavy-atom methods and refined anisotropicaily to R and Rw values of 0.025 and 0.028, respectively. The phosphine is located on the ruthenium atom trans to the Ru-Co bond and equatorially cis to the μ-PPh2 group. The Ru-Co distance is 2.7681 (4) A?, and the Ru-P (1)-Co angle at the phosphide bridge is 75.5 (0)°. The ruthenium atom has quasi-octahedral stereochemistry while the cobalt atom coordination sphere can be described as a severely distorted square pyramid. 31P NMR studies have demonstrated that monosubstitution occurs exclusively on the ruthenium atom and at equatorial sites generating mixtures of two geometrical isomers readily distinguishable in solution. Selectivity toward substitution on the ruthenium atom has also been observed for disubstitution. The product (PPh2H)2(CO)2Ru(μ-PPh 2)Co(CO)3, 4 (L = PPh2H), has an exceedingly complex 31P NMR spectrum in solution due to the presence of four isomeric structures arising from the mutual arrangement of two phosphines and a phosphido bridge around the ruthenium atom. A complete analysis of the spectrum of 4 (L = PPh2H) by the COSY NMR technique is presented.
