22569-53-5Relevant articles and documents
In situ high pressure FT-IR spectroscopy on alkene hydroformylation catalysed by RhH(CO)(PPh3)3 and Co2(CO) 8
Caporali, Maria,Frediani, Piero,Salvini, Antonella,Laurenczy, Gabor
, p. 4537 - 4543 (2004)
Catalytic hydroformylation of olefins studied by HP FT-IR cell using RhH(CO)(PPh3)3 catalytic precursor shows a different behaviour between a terminal and an internal alkene. Different rate-determining steps have been hypothesised. Catalytic hydroformylation of olefins has been carried out in a HP FT-IR cell using RhH(CO)(PPh3)3 catalytic precursor. A different behaviour was noticed between a terminal (hex-1-ene) and an internal alkene (cyclohexene) and different rate-determining steps of the catalytic cycle have been hypothesised. The hydroformylation of hex-1-ene has also been tested in the presence of Co2(CO)8 as catalyst. In this case, only the catalytic precursor is evidenced by HP FT-IR. Finally, the influence of an additional gas (helium, nitrogen or argon) in the reaction medium was evaluated: a high pressure of argon or nitrogen affects the initial rate of the reaction as shown by a decrease of the rate of the aldehyde formation.
In Situ High-Pressure 31P{1H} NMR Studies of the Hydroformylation of 1-Hexene by RhH(CO)(PPh3)3
Bianchini, Claudio,Lee, Hon Man,Meli, Andrea,Vizza, Francesco
, p. 849 - 852 (2000)
The hydroformylation of 1-hexene with syngas (40 bar of 1:1 CO/H2) in the presence of the catalyst precursor RhH(CO)(PPh3)3 has been studied by high-pressure NMR spectroscopy in a 10 mm sapphire tube equipped with a Ti-alloy valve. Except for RhH(CO)2(PPh3)2, no direct observation of labile intermediates involved in the catalytic cycle has been detected; however as many as four rhodium resting states have been seen, and some factors controlling their formation/interconversion/inhibition have been identified. The information gathered from this in situ investigation is particularly relevant to a better understanding of the inhibiting action of the CO pressure as well as the positive action of PPh3 addition.
Synthesis and characterisation of two novel Rh(I) carbene complexes: Crystal structure of [Rh(acac)(CO)(L1)]
Datt, Michael S.,Nair, Jerald J.,Otto, Stefanus
, p. 3422 - 3426 (2005)
The [Rh(acac)(CO)(L)] (acac = acetylacetonato; L1 = 1,3-bis-(2,6-diisopropylphenyl)imidazolinylidene and L2 = 1,3-bis-(2,4,6-trimethylphenyl)imidazolinylidene) complexes were prepared by the action of the parent carbene on [Rh(acac)(CO)2] in THF. The crystal structure characterisation of [Rh(acac)(CO)(L1)] revealed a slightly distorted square planar geometry with the carbene ligand orientated almost perpendicular to the equatorial plane; an elongated trans Rh-O bond of 2.0806(18) ? reflecting the considerable trans-influence of the carbene ligand. By measuring the CO stretching frequencies in a range of [Rh(acac)(CO)(L)] complexes (L = CO, L1, L2, PPh 3, PnBu3, P(O-2,4-tBu 2-Ph)3) the following electron donating ability series was established: L1 ～ L2 ～ PnBu 3 > PPh3 > P(O-2,4-tBu 2-Ph)3 > CO; indicating the carbenes investigated in this study to have a similar electronic cis-influence as trialkyl phosphines. Both complexes do not display hydroformylation activity towards 1-hexene in the absence of added phosphine or phosphite ligands under the conditions investigated (P = 60; T = 85 °C). In the presence of a phosphine or phosphite ligand the resulting hydroformylation catalysis was identical to that observed for [Rh(acac)(CO)2] and the corresponding ligand and subsequent high-pressure 31P NMR studies confirmed substitution of the carbene ligand under these conditions.
Supraphos: A supramolecular strategy to prepare bidentate ligands
Reek, Joost N.H.,R?der, Marc,Goudriaan, P. Elsbeth,Kamer, Paul C.J.,Van Leeuwen, Piet W.N.M.,Slagt, Vincent F.
, p. 4505 - 4516 (2007/10/03)
Herein, we report a new strategy for the preparation of chelating bidentate ligands, which involves the mixing of two mondentate ligands functionalized with complementary binding sites. The assembly process is based on selective metal-ligand interactions
