800369-69-1Relevant academic research and scientific papers
Ethylene tri-/tetramerization catalysts supported by diphosphinoindole ligands
Liu, Yao,Ma, Xufeng,Mi, Puke,Wang, Zhichao,Zhang, Jun,Zhao, Xing
, (2021/12/01)
A new class of diphosphinoindole ligands have been developed. Upon activation with MMAO-3A, Cr catalysts supported by these bisphosphine ligands are active for ethylene tri-/tetramerization. The best result was achieved by using the bisphosphine ligand containing a phenyl group at C3 position of indole, giving a high activity of up to 364 kg/(g Cr/h) with a total selectivity of up to 72% toward 1-hexene (23.5%) and 1-octene (48.4%). A representative chromium tetracarbonyl complex was synthesized and structurally characterized by single-crystal X-ray diffraction.
Pincer ligands with an all-phosphorus donor set: Subtle differences between rhodium and palladium
Bauer, Richard C.,Gloaguen, Yann,Lutz, Martin,Reek, Joost N. H.,De Bruin, Bas,Van Der Vlugt, Jarl Ivar
scheme or table, p. 8822 - 8829 (2011/10/17)
The synthesis of a new, all-phosphorus pincer PPNEt2P ligand L3NEt2, which is derived from 2-indolylphosphine and features a central N2P(NEt2) core, is described. This 'PPP' species shows coordination toward Rh as a neutral trisphosphine ligand. Tridentate diphenylphosphine-derived PPHP ligands L1H and L2 H, featuring a secondary phosphine core, show 'ambivalent' coordination, acting as persistent neutral triphosphine ligands with Rh, and as easily-formed monoanionic phosphido(bisphosphine) pincer ligands toward Pd. These subtle differences, which might be more general for group 9 and 10 metal complexes with this ligand set, are explained by comparative DFT calculations (BP86; def2-TZVP level of theory) for the Rh and Pd species involved, including those with the structurally related PNHP ligands. The optimized structure for complex PdCl(L2) indicates minimal overlap of available Pd d-orbitals with the lone pair of the central, deprotonated phosphorus atom (formally a phosphido fragment), suggesting that it behaves predominantly like a bulky phosphine instead of a phosphido fragment. The Royal Society of Chemistry 2011.
Asymmetric hydrogenation with highly active IndolPhos-Rh catalysts: Kinetics and reaction mechanism
Wassenaar, Jeroen,Kuil, Mark,Lutz, Martin,Spek, Anthony L.,Reek, Joost N. H.
scheme or table, p. 6509 - 6517 (2010/09/11)
The mechanism of the IndolPhos-Rh-catalyzed asymmetric hydrogenation of prochiral olefins has been investigated by means of X-ray crystal structure determination, kinetic measurements, high-pressure NMR spectroscopy, and DFT calculations. The mechanistic study indicates that the reaction follows an unsaturate/dihydride mechanism according to Michaelis Menten kinetics. A large value of KM (KM = 5.01 ± 0.16 M) is obtained, which indicates that the Rh-solvate complex is the catalyst resting state, which has been observed by high-pressure NMR spectroscopy. DFT calculations on the substrate-catalyst complexes, which are undetectable by experimental means, suggest that the major substrate-catalyst complex leads to the product. Such a mechanism is in accordance with previous studies on the mechanism of asymmetric hydrogenation reactions with C1-symmetric heteroditopic and monodentate ligands.
Versatile new C3-symmetric tripodal tetraphosphine ligands; structural flexibility to stabilize Culand Rhl species and tune their reactivity
Wassenaar, Jeroen,Siegler, Maxime A.,Spek, Anthony L.,De Bruin, Bas,Reek, Joost N. H.,Van Vlugt, Jarl Ivar Der
scheme or table, p. 6495 - 6508 (2010/10/04)
The high-yielding synthesis and detailed characterization of two well-defined, linkage isomeric tripodal, tetradentate allphosphorus ligands 1-3 Is described. Coordination to Cul resulted in formation of complexes 4-6, for which the molecular structures indicate overall tridentate coordination to the copper atom in the solid state, with one dangling peripheral phosphine. The solution studies suggest fast exchange between the three phosphine side-arms. For these new Cul complexes, preliminary catalytic activity In the cyclopropanation of styrene with ethyldiazoacetate (EDA) is disclosed. The anticipated well-defined tetradentate coordination in a C 3-symmetric fashion was achieved with Rhl and lr l, leading to the overall five-coordinated complexes 7-12. Complex 11 has the norbornadiene (nbd) ligand coordinated in an unprecedented monodentate 2,3-η2 mode to Rh. Furthermore, unexpected but very interesting redox-chemistry and reactivity was displayed by the Rh(Cl)-complexes 7 and 8. Oxidation resulted In the formation of stable Rhll metalloradicals [7]PF6 and [8]PF6 that were characterized by X-ray crystallography, magnetic susceptibility measurements, cyclic voltammetry, and electron paramagnetic resonance (EPR) spectroscopy. Subsequent redox-reactivity of these metalloradicals toward molecular hydrogen is described, resulting in the formation of Rhlll hydride compounds.
Asymmetric synthesis of the Roche ester and its derivatives by rhodium-INDOLPHOS-catalyzed hydrogenation
Wassenaar, Jeroen,Kuil, Mark,Reek, Joost N. H.
experimental part, p. 1610 - 1614 (2009/07/18)
(S)-3-Hydroxy-2-methylpropionate, known as the Roche ester, and several of its derivatives were successfully synthesized through asymmetric rhodium-catalyzed hydrogenation, using INDOLPHOS (diisopropyl{1-[(S)-3,5-dioxa- 4-phosphacyclohepta[ 2,1-a;3,4-a′]dinaphthalen-4-yl]-3-methyl-2-indolyl} phosphine) as the chiral ligand, in excellent yield and the highest ee reported up to now (TOF over 5500 h-1 at 25°C; up to 98% ee at -40°C).
INDOLPhos: novel hybrid phosphine-phosphoramidite ligands for asymmetric hydrogenation and hydroformylation
Wassenaar, Jeroen,Reek, Joost N. H.
, p. 3750 - 3753 (2008/03/13)
Hybrid bidentate phosphine-phosphoramidite ligands are prepared in a modular 2-step sequence and their rhodium complexes display high selectivity in rhodium catalysed hydrogenation and hydroformylation reactions. The Royal Society of Chemistry.
