19531-77-2Relevant academic research and scientific papers
Synthesis, structure, and ligand-promoted reductive elimination in an acylrhodium ethyl complex
Suggs, J. William,Wovkulich, Michael J.,Cox, Sherman D.
, p. 1101 - 1107 (1985)
8-Quinolinecarboxaldehyde and [(C2H4)2RhCl]2 reacted to give a polymeric acylrhodium ethyl compound which was solubilized by pyridine to give chloroethyl(8-quinolinecarbonyl-C,N)(pyridine)rhodium. This compound was stable in the presence of amine ligands, but phosphine ligands caused rapid reductive elimination. Intermediates in the reductive elimination were observed at -40°C by using 1H, 13C, and 31P NMR in the case of the ligand PPh3. In the first-formed intermediate PPh3 displaced pyridine. The resulting five-coordinated Rh(III) complex reductively eliminated (with an observed first-order rate constant of 3.7 × 10-4 s-1 at -40°C) to give an η2-ketone Rh(I) intermediate. With excess phosphine RhCl(PPh3)3 and 8-quinolinyl ethyl ketone were the final products. Recrystallization of the starting pyridine complex from pyridine-ether gave Cl(C2H5)Rh(C10H6NO)(C 5H5N)2·1/2C 4H10O (chloroethyl(8-quinolinecarbonyl-C,N)bis(pyridine)rhodium-hemi(diethyl ether)), whose structure was determined by single-crystal X-ray diffraction. The compound crystallizes in the triclinic space group P1 with two molecules in the unit cell a = 8.933 (3) A?, b = 17.573 (8) A?, c = 7.760 (2) A?, α = 97.57 (3)°, β = 98.04 (2)°, and γ = 79.98 (3)°. The least-squares refinement with anisotropic thermal parameters for all non-hydrogen atoms converged at RF = 0.046 (RwF = 0.055) for 2595 observed reflections and 262 parameters refined.
Direct use of chiral or achiral organophosphorus boranes as pro-ligands for transition metal catalyzed reactions
Darcel, Christophe,Kaloun, El Bachir,Merdès, Rachid,Moulin, Dominique,Riegel, Nadège,Thorimbert, Serge,Genêt, Jean Pierre,Jugé, Sylvain
, p. 333 - 343 (2007/10/03)
Chiral or achiral organophosphorus borane complexes were used without isolation of the free tricoordinate P(III) ligand; thus, the borane adducts could be used either directly with metal salts to perform the catalysis, or they could be decomplexed by DABCO, or cyclooctadiene, and used in situ to generate the catalytic species. Chiral copper, palladium and rhodium complexes prepared using this method, were tested in asymmetric organometallic catalyzed 1,4-addition to 2-cyclohexenone, allylation of Schiff base and hydrogenation of α-acetamidocinnamic acid derivatives, respectively.
Activation of dichloromethane by (phosphane)nrhodium(I) Complexes - X-ray structure of [{(PEt3)2RhCl}2(μ-Cl) 2(μ-CH2)]
Brunet, Jean-Jacques,Couillens, Xavier,Daran, Jean-Claude,Diallo, Ousmane,Lepetit, Christine,Neibecker, Denis
, p. 349 - 353 (2007/10/03)
Dichloromethane reacts with dinuclear rhodium complexes [{(PR3)2Rh}2(μ-Cl)2] to give the bridging-methylene complexes [{(PR3)2(μ-Cl)2(μ-CH2)] (PR3 = PEtsub
An NMR spectroscopic study of the reactions of (2-(2-methoxyethoxy)ethyl)diphenylphosphine with rhodium(I) olefin complexes
Reddy, V. Vijay Sen,Varshney, Ashima,Gray, Gary M.
, p. 259 - 266 (2007/10/02)
The reactions of Ph2P(CH2CH2O)2CH3 (I) with 2 and 2 (cod = 1,5-cyclooctadiene, coe = cis-cyclooctene) and of Ph2PMe with 2 have been studied using 31P and 13C NMR spectroscopy.These studies indicate that the two Rh complexes give quite different reaction products.The reaction of I with 2 at a Rh/I ratio of 1/1 yields (cod)RhCl (II).Increasing the Rh/I ratio in this solution to 1/2 results in the formation of ClRh3 (III), but not of any complexes with two I's coordina ted to Rh.A complex with two I's attached to the Rh can be formed by first reacting II with AgBF4 to form >BF4 (IV) and then by reacting IV with a second equivalent of I to form 2>BF4 (V).The reaction of 2 with Ph2PMe yields 2 (VI) at a Rh/Ph2PMe ratio of 1/1, 2 (VII) at a Rh/Ph2PMe ratio of 1/2 and ClRh(Ph2PMe)3 (VIII) at a Rh/Ph2PMe ratio of 1/3.The reaction of2 with I gives a different product, Rh(μ-Cl)>2 (IX) at a Rh/I ratio of 1/1, but similar products at Rh/I ratios of 1/2, 2Rh(μ-Cl)>2 (XI) and 1/3, III.The differences in the reaction products are due to the fact that the bidentate cod ligand coordinates much more strongly to the Rh than do either the bridging chlorine of the monodentate coe ligand.Thus, the reactions of 2 with phosphines initially involve displacement of the bridging chloride, but those of 2 with phosphines initially involve loss of the coe ligand.The weak Rh-coe bond allows I to function as a chelating P/O-ligand in IX.
The preparation and nuclear magnetic resonance spectra of hydridophosphine complexes of ruthenium and rhodium
Dewhirst,Keim,Reilly
, p. 546 - 551 (2008/10/08)
The preparations of the complexes H2Ru((C6H5)2PCH3) 4, H2Ru(CO)C((6H5)2PCH 3)3 HRh((C6H5)3P)4, HRh((C6H5)3P)4, HRh((C6H5)3P)3, HRh((C6H5)2PCH3)4, ((C6H5)2PCH3)3RhCl, and ((C6H5)2PCH3)2(CO)RhCl are described. The nmr spectra of these complexes are discussed with regard to possible structures. The results confirm a rapid ligand exchange in these types of compounds.
