- Dinuclear Phosphine-Amido [Rh2(diene){μ-NH(CH2)3PPh2}2] Complexes as Efficient Catalyst Precursors for Phenylacetylene Polymerization
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Dinuclear phosphine-amido, [Rh2(diene){μ-NH(CH2)3PPh2}2], and cationic phosphine-amino complexes, [Rh(diene){Ph2P(CH2)3NHR}]+ (diene = cod, nbd, tfb) and [Rh{Ph2P(CH2)3NHR}2]+, have been prepared from the corresponding amino-functionalized phosphines Ph2P(CH2)3NHR (R = H, Me) and suitable rhodium(I) precursors. The dinuclear [Rh2(diene){μ-NH(CH2)3PPh2}2] complexes bearing π-acceptors diene ligands such as nbd or tfb exhibit a remarkable catalytic activity in phenylacetylene (PA) polymerization affording stereoregular polyphenylacetylenes with, unlike the cod precursor, unimodal molar mass distributions of very high molecular weights, Mw up to ≈ 1.2 × 106, and moderate polydispersity indexes. These complexes are more active than the mononuclear phosphino-anilido [Rh(diene){Ph2P(C6H4)NMe}] complexes, which are in turn more active than the cationic complexes [Rh(diene){Ph2P(CH2)3NHMe}]+, [Rh(nbd){Ph2P(CH2)3NH2}]+, and [Rh(nbd){Ph2P(C6H4)NHMe}]+ bearing the same diene ligand. In contrast, complexes [Rh{Ph2P(CH2)3NHR}2]+ (R = H, Me) without a diene ligand have been found to be inactive in PA polymerization. The excellent catalytic performance of [Rh2(diene){μ-NH(CH2)3PPh2}2] (diene = nbd, tfb) complexes is a consequence of the mode of activation of PA that likely results in the formation of unsaturated alkynyl species [Rh(diene)(CC-Ph)L] (L = PA, THF), which may be competent for PA polymerization.
- Angoy, Marta,Jiménez, M. Victoria,García-Ordu?a, Pilar,Oro, Luis A.,Vispe, Eugenio,Pérez-Torrente, Jesús J.
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- Cobalt Phosphino-α-Iminopyridine-Catalyzed Hydrofunctionalization of Alkenes: Catalyst Development and Mechanistic Analysis
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A family of CoCl2(PNpy) complexes were prepared, where PNpy = 2-iminopyridyl-phosphine ligands derived from aminoalkyl and aminoaryl phosphines and 2-keto- and 2-formylpyridines. Reduction of CoCl2(PNpy) complexes in the presence of
- Chu, Wan-Yi,Gilbert-Wilson, Ryan,Rauchfuss, Thomas B.,Van Gastel, Maurice,Neese, Frank
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supporting information
p. 2900 - 2914
(2016/11/02)
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- Phosphorus-based functional groups as hydrogen bonding templates for rotaxane formation
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We report on the use of the hydrogen bond acceptor properties of some phosphorus-containing functional groups for the assembly of a series of [2]rotaxanes. Phosphinamides, and the homologous thio- and selenophosphinamides, act as hydrogen bond acceptors t
- Ahmed, Rehan,Altieri, Andrea,DSouza, Daniel M.,Leigh, David A.,Mullen, Kathleen M.,Papmeyer, Marcus,Slawin, Alexandra M. Z.,Wong, Jenny K. Y.,Woollins, J. Derek
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supporting information; experimental part
p. 12304 - 12310
(2011/10/01)
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- Aminophosphine ligands R2P(CH2)nNH 2 and ruthenium hydrogenation catalysts RuCl2(R 2P(CH2)nNH2)2
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The aminophosphine ligands R2P(CH2) 2NH2 and R2P(CH2)3NH 2 (R = Ph, iPr, tBu) were isolated in good to excellent yields from the reaction of LiPR2 with Cl(CH 2)2N(TMS)2 and Cl(CH2) 3N(TMS)2, respectively, followed by hydrolysis. This approach allows fine tuning of the ligands' stereoelectronic properties through the variation of the substituents on the phosphine. The aminophosphine ligands were used to prepare the ruthenium complexes RuCl2(R 2P(CH2)2NH2)2 and RuCl2(R2P(CH2)3NH2) 2 by reacting a 2:1 mixture of the respective ligand and [RuCl 2(cod)]n in an appropriate solvent. The resulting complexes were found to be excellent catalysts for the hydrogenation of ketones and imines. The Royal Society of Chemistry 2009.
- Jia, Wenli,Chen, Xuanhua,Guo, Rongwei,Sui-Seng, Christine,Amoroso, Dino,Lough, Alan J.,Abdur-Rashid, Kamaluddin
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experimental part
p. 8301 - 8307
(2010/03/04)
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- Preparation of a Nafion-Teflon bimembrane-supported palladium catalyst and its use in the Heck reaction
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A novel palladium catalyst supported on the Nafion membrane, reinforced with poly(tetrafluoroethylene) fiber, has been prepared. The catalyst exhibits high activity and stability in the Heck arylation reactions of aryl iodides with olefins and Sonogashira couplings with phenylacetylene, and can be readily recovered and reused twenty times without significant loss of activity.
- Li, Yangzhou,Li, Zhiming,Li, Feng,Wang, Quanrui,Tao, Fenggang
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p. 6159 - 6162
(2007/10/03)
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- Polymer bound Pd(0) phosphine catalyst for homogeneous catalysis
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Facile synthesis of water-soluble polymer bound Pd(0) phosphine catalyst is described. This recyclable polymeric catalyst is soluble in aqueous or aqueous/organic media and has high activity in nucleophilic allylic substitution, Heck reaction and hydrogenation.
- Koshti, Nirmal,Naik, Shubhangi,Parab, Bharat
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p. 852 - 856
(2007/10/03)
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- Control of aminophosphine chelate ring-opening in Pt(II) and Pd(II) complexes: Potential dual-mode anticancer agents
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We show that bis(aminophosphine) complexes of the type [M(R1R2N(CH2)nPPh2)2 ]2+, M = Pt(II) or Pd(II), can exist in chelate ring-closed and ring-opened forms both in the solid state and in aqueous solution. The equilibrium between them in solution can be controlled by the nature of the groups R1 and R2 (H, Me, Bz, cyclohexyl), by the bridge length n, and by the pH and Cl- concentration. X-Ray crystal structures are reported for the ring-closed complexes cis-[Pt(H2N(CH2)2PPh2-P,N)2 ]Cl2, cis-[Pt(H2N(CH2)3PPh2-P,N)2 ]Cl2, and cis-[Pt(Me(H)N(CH2)2PPh2-P,N)2][HCl 2]2, the mono-ring-opened complex cis-[Pd(Me2N(CH2)2PPh2-N,P)Cl(Me 2NH(CH2)2PPh2-P)](NO3) 2, the di-ring-opened complex cis-[Pt(Me2N(CH2)3PPh2-P)2 CL2], and, for comparison, the monochelate cis-[Pd(Me2N(CH2)3PPh2-N,P)CL2 ]. These square-planar complexes exhibit varying degrees of distortion and variable M-N bond lengths dependent not only on the trans influence of P but also on steric effects within the complex, pH-induced chelate ring-opening of cis-[Pt(Me2N(CH2)2PPh2-P,N)2 ]CL2 had an associated pK value of 6.9. In contrast, complexes with R1 and R2 = H, n = 2 or 3 or R1 = H and R2 = Me, n = 2, are more difficult to ring-open. Thus the complexes cis-[Pt(Me(H)N(CH2)2-PPh2-P,N)2]CL 2 and cis-[Pt(H2N(CH2)3PPh2-P,N)2 ]CL2, had associated pK values of 2.1 and 2.9, respectively. These aminophosphine complexes may exhibit anticancer activity by two mechanisms: by disrupting mitochondrial membrane potentials as bis-chelated (ring-closed) lipophilic cations, or by direct binding to DNA bases as ring-opened complexes.
- Habtemanam, Abraha,Watchman, Beth,Potter, Brian S.,Palmer, Rex,Parsons, Simon,Parkin, Andrew,Sadler, Peter J.
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p. 1306 - 1318
(2007/10/03)
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- Synthesis and investigation of phosphine ligands containing cationic guanidino functions in aqueous Heck reactions
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Phosphines 2 and 3 supplemented with strongly basic and hydrophilic guanidium functions were prepared for the first time. In combination with palladium acetate these ligands form active catalysts that promote an aqueous Heck reaction.
- Dibowski, Harald,Schmidtchen, Franz P.
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p. 2325 - 2330
(2007/10/02)
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- Preparation and Characterization of Cobalt(III) Complexes Containing 4,7-Diphenyl-4,7-diphosphadecane-1,10-diamine and 4,8-Diphenyl-4,8-diphosphaundecane-1,11-diamine, NH2(CH2)3P(C6H5)(CH2)nP(C6H5)(CH2)3NH2 (n=2,3)
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Twelve new cobalt(III) complexes of the types, cisα-p+ (L=2,4-pentanedionate (acac) and oxalate (ox) ions) (four complexes) and cisβ-p+ (eight complexes) were prepared and characterized by 1H NMR and absorption spectra, where rac(P)- and meso(P)-323NPPN denote rac(P)- and meso(P)-NH2(CH2)mP(C6H5)(CH2)nP(C6H5)(CH2)mNH2 with m=3 and n=2, and 333NPPN the ligand with m=3 and n=3.Reactivities of the complexes towards hydrochloric acid were examined and compared with those of the corresponding 222NPPN (m=2, n=2) and 232NPPN (m=2, n=3) complexes.All the cisα isomers yield the cisα-dichloro complexes, the 333NPPN and 222NPPN complexes being more reactive than the 232NPPN and 323NPPN complexes in which five- and six-membered chelate rings of NPPN are involved.For the cisβ isomers, the acac complexes afford +)>2+ except the rac(P)- and meso(P)-333NPPN complexes which give the trans-dichloro complexes, while all the ox complexes liberate the ox ion to yield the dichloro complex of the cisα, cisβ, or trans configuration.For both cisβ-acac and -ox isomers, the 222NPPN and 232NPPN complexes are more reactive than those of 323NPPN and 333NPPN, and the meso(P)-complexes are more reactive than the rac(P)-complexes.
- Kashiwabara, Kazuo,Jung, Minho,Fujita, Junnosuke
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p. 2372 - 2377
(2007/10/02)
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- Addition of diphenylphosphine to Michael-type olefins: the preparation of phosphine-nitrile and phosphine-ester ligands
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The reactions of five Michael-type olefins with diphenylphosphine have been carried out. 1-Cyanocyclopentene, 1-cyanocyclohexene, and 4-t-butyl-1-cyanocyclohexene all provide the corresponding 2-diphenylphosphino-1-cyanocycloalkanes, and both methyl acrylate and ethyl methacrylate yield to corresponding 2-diphenylphosphinopropionates.For the products from 1-cyanocyclopentene and 1-cyanocyclohexene, 13C and 31P NMR data are consistent with the formation of both trans (Ph2P equatorial and CN axial) and cis (both Ph2P and CN equatorial) isomers.The morpholine amide of 3-diphenylphosphinopropionic acid has been obtained by treatment of methyl-3-diphenylphosphinopropionate with the dimethylaluminum adduct of morpholine.This phosphine, Ph2Pmorph, has been isolated as its palladium(II) complex, (Ph2Pmorph)2PdCl2.A phosphine-benzaldimine, Ph2P(CH2)3NC(H)C6H5, has been obtained by reacting Ph2P(CH2)3NH2, from the reduction of PhP(CH2)2CN, with benzaldehyde in the presence of molecular sieves.
- Blinn, D.A.,Button, R.S.,Farazi, V.,Neeb, M.K.,Tapley, C.L.,et al.
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p. 143 - 152
(2007/10/02)
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- Pentamethylcyclopentadienylrhodium Complexes with Tripoid Tetradentate Ligands and Bidentate 'Mixed' Ligands
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The synthesis and properties of the complexes 3Cl5L>Y , obtained from and the appropriate tripodal tetradentate ligands, L=N(CH2CH2PPh2)3 or P(CH2CH2PPh2)3, are reported.These monoligand trimetallic compounds contain two Rh(C5Me5)Cl2 units each bound to a terminal phosphorus atom of the tripod ligand and a Rh(C5Me5)Cl group linked to the third terminal phosphorus and to the apical donor atom, nitrogen for N(CH2CH2PPh2)3, phosphorus for P(CH2CH2)3.The Rh(C5Me5)Cl group in the N(CH2CH2PPh2)3 derivative undergoes substitution when treated with tetrabutylammonium chloride to give 3>.The influence of steric factors in the substitution reaction has been investigated by synthesising and characterising the complexes >BPh4 (n=2, R=Ph or C6H11, R'=H, Me or Et; n=3, R=Ph, R'=H, Me or Et; R=C6H11, R'=H or Me).The bidentate mixed ligands R'2N(CH2)nPPh2 (n=2, R'=Et; n=3, R'=Me or Et) give complexes of formula 2>BPh4, in which the ligands are monodentate through the phosphorus atom.The crystal structure of 2>BPh4 has been determinated by X-ray crystallographic analysis.The complexes 2>BPh4 (n=2, R'=Et; n=3, R'=Me) exist as four rotamers due to restricted rotations of the bulky phosphine substituents about the Rh-P bonds, as shown by low-temperature 31P n.m.r. spectroscopy.
- Stoppioni, Piero,Vaira, Massimo Di,Maitlis, Peter M.
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p. 1147 - 1154
(2007/10/02)
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