32762-45-1Relevant articles and documents
High-pressure effects in the homogeneously catalyzed hydroformylation of olefins
Albers, Joern,Dinjus, Eckhard,Pitter, Stephan,Walter, Olaf
, p. 41 - 46 (2004)
The homogeneously catalyzed hydroformylation of linear olefins (octenes and butanes) was studied at 7-550 MPa. At high-pressures, the yields of aldehydes generally increased. Lower l/b ratios at higher pressures resulted from the formation of an unmodified rhodium catalyst. Isomerization of the olefin prior to hydroformylation was completely suppressed in the conversion of 1-octene at high-pressures, while the isomerization of 4-octene led to a mixture of all possible aldehydes. Isomerization of 4-octene was less hindered at high-pressures than was the isomerization of 1-octene. The pressure effect on the isomerization rates was a kinetic effect. Yields of hydroformylation of sterically hindered, substituted butenes increased at high-pressures.
Rh(I) and Ir(I) derivatives of a P(S),N-substituted indene ligand: Synthetic, structural, and catalytic alkene hydrosilylation studies
Wechsler, Dominik,Myers, Anne,McDonald, Robert,Ferguson, Michael J.,Stradiotto, Mark
, p. 4562 - 4570 (2006)
Treatment of 1-PiPr2-indene or 1-PiPr 2-2-NMe2-indene (1a) with elemental sulfur afforded 3-iPr2P(S)-indene or 1-iPr2P(S)-2- NMe2-indene (4a) in 81% and 85% isolated yield, respectively. Addition of 4a to [(COD)M(THF)2]+BF4 - afforded the corresponding [(COD)M(κ2-N,S-4a)] +BF4- complexes (M = Rh, 5a, 76%; M = Ir, 5b, 59%; COD = η4-1,5-cyclooctadiene), which were found to exhibit temperature-dependent NMR spectral features that were rationalized in terms of a dynamic process involving M-NMe2 dissociation, rotation about the indenyl-NMe2 bond, inversion at nitrogen, and re-coordination to M. Analysis of variable-temperature NMR data collected for 5a and 5b each yielded a value for ΔG? of ca. 14 kcal/mol for this process. Exposure of 5a or 5b to NaN(SiMe3)2 generated the corresponding (COD)M(κ2-C,S-1-iPr 2P(S)-2-NMe2-(C1-indenyl)) complex (M = Rh, 6a, 70%; M = Ir, 6b, 86%) in which the metal is incorporated into an M-C-P-S ring via coordination to the indenyl ring in an η1-fashion, as well as to sulfur. Alternatively, complex 6b was prepared cleanly via lithiation of 4a followed by treatment with 0.5 equiv of [(COD)IrCl]2. The ability of 5a,b and 6a,b to mediate the addition of triethylsilane to styrene was also explored, and their performance was compared with that of Wilkinson's Catalyst ((PPh3)3RhCl) and Crabtree's catalyst ([(COD)Ir(PCy 3)(Py)]+PF6-; Cy = cyclohexyl; Py = pyridine). Single-crystal X-ray diffraction data are provided for 4a, 2-NMe 2-3-iPr2P(S)-indene (4b), 6a, and 6b.
Dihydrido Olefin and Solvento Complexes of Iridium and the Mechanisms of Olefin Hydrogenation and Alkane Dehydrogenation
Crabtree, Robert H.,Demou, Peter C.,Eden, Don,Mihelcic, Jean M.,Parnell, Charles A.,et al.
, p. 6994 - 7001 (2007/10/02)
Tests for homogeneity are applied to the catalysts L2>A/CH2Cl2/H2 (cod-1,5-cyclooctadiene; A = BF4; L=PPh3, PMePh2) and their possible generality is discussed. L2>A (L=PPh3) reacts with H2 and S (S=solvent) to give the isolable complexes IrH2S2L2>A (1) in which the displacement order of the M-S groups is H2O ca.THF2L2>A (ol = C2H4, C3H8) and L2>A (ol = PhCH=CH2, C5H8, t-BuCH=CH2).Their role in hydrogenation is discussed in the light of stepwise catalytic 1H NMR studies at -80 to +25 deg C, in which they appear to be intermediates in catalysis.A catalytic cycle is proposed.Selectivity in competitive experiments is discussed.The rhodium analogues do no exhibit similar properties.
