38425-01-3Relevant articles and documents
Rattray, Alexander D.,Sutton, Derek
, p. L85 - L86 (1978)
Acid-catalysed Additions of Acetylenes to (X=Cl, Br, or I) to give Dimetallated Olefin Complexes of Type (R=H, Ph, or C6H4Me-p)
Higgins, Simon J.,Shaw, Bernard L.
, p. 457 - 460 (1988)
The addition of acetylenes to (dppm=Ph2PCH2PPh2; X=Cl, Br, or I) is catalysed by traces of acid and (in some cases) methanol, giving (R=H, Ph, or C6H4Me-p) containig the dipalladated olefin ligand HC=CR.These r
Khan, Masood A.,McAlees, Alan J.
, p. 109 - 114 (1985)
Variable bonding modes of pyrimidine-2-thione in PdII/Pt II complexes [M(η2-N, S-pymS)(η1-S- pymS)(PPh3)] and [M(η1-S-pymS)2(L-L)] (L-L = dppm, dppe)
Lobana, Tarlok S.,Kaur, Parminderjit,Hundal, Geeta,Butcher, Ray J.,Castineiras, Alfonso
, p. 747 - 753 (2009/04/13)
Reactions of pyrimidine-2-thione (HpymS) with PdII/Pt IV salts in the presence of triphenyl phosphine and bis(diphenylphosphino) alkanes, Ph2P-(CH2) m-PPh2 (m = 1, 2) have yielded two types of complexes, viz. (a) [M(η2-N, S- pymS)(η1-S- pymS)(PPh 3)] (M = Pd, 1; Pt, 2), and (b) [M(η1-S-pymS) 2(L-L)] {L-L, M = dppm (m = 1) Pd, 3; Pt, 4; dppe (m =2), Pd, 5; Pt, 6}. Complexes have been characterized by elemental analysis (C, H, N), NMR spectroscopy (1H, 13C, 31P), and single crystal X-ray crystallography (1, 2, 4, and 5). Complexes 1 and 2 have terminal η1-S and chelating η2-N, S-modes of pymS -, while other Pd/Pt complexes have only terminal η1-S modes. The solution state 31P NMR spectral data reveal dynamic equilibrium for the complexes 3, 5 and 6, whereas the complexes 1, 2 and 4 are static in solution state.
The Pd4(dppm)4(H)22+ Cluster: A Precatalyst for the Homogeneous Hydrogenation of Alkynes
Evrard, David,Groison, Katherine,Mugnier, Yves,Harvey, Pierre D.
, p. 790 - 796 (2008/10/09)
The catalytic properties of the title cluster toward the homogeneous hydrogenation of phenylacetylene, diphenylethyne and phenyl-1-propyne have been investigated as a function of temperature, pressure, solvents, substrate and cluster concentrations, and counterions. The title cluster is a precatalyst that exhibits a good catalytic activity under mild conditions (1 atm of H 2 at 20 °C) for the hydrogenation of alkynes and alkenes. For the alkyne substrates, the turnover frequencies (tof's) range between 200 and 500 h-1, and the product distribution varies as: cis-products, 75-90%; trans-products; 0-8% after 3 h of reaction. Based on the graphs -d[substrate]/dt vs [Pd4]1/2, the mechanism indicates a cluster dissociation into two dimers (presumably of the type Pd 2(dppm)2(H)(solvent)+). The variations of tof (or -d[substrate]/dt) as a function of [substrate] and pressure of H 2 are linear. At 1600 psi of H2, the tof can reach 2500-3000 h-1 (in THF). The tof also increases with temperature reaching a maximum at ～35 °C (tof: 1000-1300 h-1), but at higher temperatures cluster decomposition begins to occur, leading to a rapid decrease in rates of catalysis. At 50 °C, no catalysis is observed. The hydrogenation reaction can be stopped at the corresponding cis-alkenes with ～95% yields, depending on the substrate and experimental conditions used. The tof's also vary with the solvent, where stronger coordinating solvent molecules give higher tof's. In addition, the tof's do not change with the nature of the counterion, which acts as spectator in the catalysis.
