- Reactions of phosphinites with oxide surfaces: A new method for anchoring organic and organometallic complexes
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When a pincer-ligated iridium complex with a phosphinite substituent in the para-position of the aromatic backbone is immobilized on γ-alumina, it becomes a highly effective supported catalyst for the transfer-dehydrogenation of alkanes. The nature of the interaction between the organometallic complex and the support was investigated using solid-state 31P MAS NMR spectroscopy, solution-state 1H and 31P{1H} NMR spectroscopy, IR and GC/MS analysis of extracted reaction products. The phosphinite substituent is cleaved from the pincer ligand by its reaction with hydroxyl groups on the γ-alumina surface, resulting in covalent anchoring of the complex via the aryl ring. A similar reaction occurs on silica, allowing for ready grafting onto this support as well. A strategy for anchoring homogeneous catalysts on hydroxyl-terminated oxide supports though the selective cleavage of [POR]-containing ligand substituents is suggested.
- Vicente, Brian C.,Huang, Zheng,Brookhart, Maurice,Goldman, Alan S.,Scott, Susannah L.
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supporting information; body text
p. 4268 - 4274
(2011/06/23)
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- Coordination Chemistry of P-Rich Phosphanes and Silylphosphanes. XXVI [1] Formation and Structure of [{cyclo-P4(P(t)Bu2)4}{Ni(CO)2}2]
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[{cyclo-P4(P(t)Bu2)4}{Ni(CO)2}2] is formed by reaction of the cyclotetraphosphane P4(P(t)Bu2)4 with [Ni(CO)4]. Each Ni(CO)2 unit is coordinated by two adjacent (t)Bu2P groups forming two five-membered P4Ni rings above and below the planar cyclotetraphosphane ring, respectively. The compound crystallizes in the triclinic space group P1- (No. 2) with a=893.29(5), b=1140.75(7), c=1235.52(8) pm, α=109.179(7), β=100.066(7), γ=97.595(7)° and Z=1.
- Krautscheid, Harald,Matern, Eberhard,Olkowska-Oetzel, Jolanta,Pikies, Jerzy,Fritz, Gerhard
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- Rhodium-catalyzed dehydrocoupling of the sterically encumbered phosphine-borane adduct tBu2PH·BH3: Synthesis of the linear dimers tBu2PH-BH2-tBu2P-BH3 and tBu2PH-BH2-t
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The dehydrocoupling of the sterically hindered phosphine-borane adduct tBu2PH·BH3 above 140 °C is catalyzed by the rhodium complexes [Rh(1,5-cod)2:][OTf] or Rh6(CO)16 to give the four-membered chain tBu2/s
- Dorn,Vejzovic,Lough,Manners
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p. 4327 - 4331
(2008/10/08)
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- Oxidative Additionen an 2-Amino-4,4,5,5-tetrakis(trifluormethyl)-1,3,2-dioxaphospholan
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Oxidative addition of HF, Cl2, and (CF3)2CO to the title compound 6 furnishes the phosphoranes 2, 9, and 3, respectively.In the case of NH4 (4) the hydrospirophosphorane 1 is obtained via a substitution reaction followed by an oxidative addition.Compound 9 is a precursor for the aminotetraalkoxyphosphoranes 5, 8, and the very stable phosphazene 10 which is formed by loss of HCl by thermolysis.Due to a slow ligand exchange the 19F NMR spectrum of phosphorane 3 exhibits eight magnetically non equivalent CF3 groups.By means of 19F homodecoupling experiments extensive through space coupling is found in the molecule.The x-ray structure analysis of 3 shows a slight distortion from the trigonal bipyramidal geometry at phosphorus.For comparison, F2PNH2 and tBu2PNH2 react with (CF3)2CO to form (CF3)2C=NH, the aminofluorophosphorane 11, F2P(=O)OCH(CF3)2 (13), tBu2P(=O)H (12) and tBu2P(=O)OCH(CF3)2 (14), respectively.
- Storzer, Werner,Roeschenthaler, Gerd-Volker,Schmutzler, Reinhard,Sheldrick, William S.
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p. 3609 - 3624
(2007/10/02)
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