24651-65-8Relevant academic research and scientific papers
HRh4 as a hydrogenation and isomerization catalyst
Coolen, H.K.A.C.,Nolte, R.J.M.,Leeuwen, P.W.N.M.
, p. 159 - 168 (1995)
The preparation and reactions of 4> (2) have been investigated.The metallation product 3> (4) has been characterized by 31P NMR spectroscopy.Catalytic hydrogenation of alkenes with 2 depends strongly on the amount of extra ligand added and the substrate (1-hexene, Z,E-2-hexene and allylbenzene).Without added phosphite, traces of 2)2> are the actual catalyst.Under these conditions the reaction is zero order in substrate.The kinetics are completely different when extra triphenyl phosphite is present.Complex 2 behaves as a catalyst with a character in between that of ClRh(PPh3)3 and cationic Rh(diphosphine)+. Keywords: Rhodium; Hydrogenation catalyst; Isomerization catalyst
Rhodium-catalyzed hydroformylation with substituted phenylphosphite ligands
Trzeciak, Anna M.,Ziolkowski, Josef J.
, p. 319 - 324 (1988)
It is shown that high catalytic activity of the system should not be expected when the formation of labile active complexes is limited by steric or other negative effects of the modifying ligands. Comparison of the results obtained in reactions with the s
New insight into role of ortho-metallation in rhodium triphenylphosphite complexes. Hydrogen mobility in hydrogenation and isomerization of unsaturated substrates
Trzeciak, Anna M.,Ziólkowski, Józef J.
, p. 69 - 76 (2007/10/03)
The hydrogen transfer from two rhodium(I) hydrido complexes HRh{P(OPh)3}4 and HRh(CO){P(OPh)3}3 to methyl acrylate and/or allylbenzene leads to the formation of ortho-metallated complexes Rh{P(OC6H4)(OPh)2}{P(OPh)3} 3 (I) and Rh{P(OC6H4)(OPh)2}(CO){P(OPh)3} 2 (II), respectively. During these reactions unsaturated substrates, methyl acrylate or allylbenzene undergo stoichiometric hydrogenation. A similar reaction was also observed for HRh{P(OR)3}4 complexes (R=3-CH3C6H4, 4-CH3C6H4). The complex HRh{P(OPh)3}4 catalyses the isomerization of hex-1-ene to hex-2-ene in the absence of H2; however at 1 atm of H2 the formation of hexane is observed. Hydrido complexes of the type HRh{P(OR)3}4 in D2 atmosphere undergo H/D exchange at the ortho position of coordinated triarylphosphite. Deuteration of the ortho protons in complexes with R=Ph, 3,5-(CH3)2C6H3 and 4-CH3C6H4 is total, whereas only one ortho hydrogen is replaced in the case of R=3-CH3C6H4. The formation of an ortho-metallated chelating ring causes a downfield shift in the 1H-NMR signal of one proton from the phenyl ring to δ ca. 8 ppm.
