- Chemo- And regioselective hydroformylation of alkenes with CO2/H2over a bifunctional catalyst
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As is well known, CO2 is an attractive renewable C1 resource and H2 is a cheap and clean reductant. Combining CO2 and H2 to prepare building blocks for high-value-added products is an attractive yet challenging topic in green chemistry. A general and selective rhodium-catalyzed hydroformylation of alkenes using CO2/H2 as a syngas surrogate is described here. With this protocol, the desired aldehydes can be obtained in up to 97% yield with 93/7 regioselectivity under mild reaction conditions (25 bar and 80 °C). The key to success is the use of a bifunctional Rh/PTA catalyst (PTA: 1,3,5-triaza-7-phosphaadamantane), which facilitates both CO2 hydrogenation and hydroformylation. Notably, monodentate PTA exhibited better activity and regioselectivity than common bidentate ligands, which might be ascribed to its built-in basic site and tris-chelated mode. Mechanistic studies indicate that the transformation proceeds through cascade steps, involving free HCOOH production through CO2 hydrogenation, fast release of CO, and rhodium-catalyzed conventional hydroformylation. Moreover, the unconventional hydroformylation pathway, in which HCOOAc acts as a direct C1 source, has also been proved to be feasible with superior regioselectivity to that of the CO pathway.
- Hua, Kaimin,Liu, Xiaofang,Wei, Baiyin,Shao, Zilong,Deng, Yuchao,Zhong, Liangshu,Wang, Hui,Sun, Yuhan
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supporting information
p. 8040 - 8046
(2021/11/01)
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- Methyl-modified cage-type phosphorus ligand and preparation method thereof Preparation method and application thereof
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The invention discloses a methyl-modified cage-type phosphorus ligand, a preparation method and application thereof, in particular to a synthesis design, wherein methyl is further introduced on a phenyl ring of triphenylphosphine, and a methyl-modified cage-type phosphorus ligand is synthesized, and when a methyl meta-substituted cage-type phosphorus ligand is used as a hydroformylation reaction catalyst the proportion of n-structural aldehyde and isomeric aldehyde is 2.6. TOF-1 The methyl-substituted cage-type phosphorus ligand is excellent in performance, stable in property and recyclable, has excellent substrate applicability in the hydroformylation catalytic reaction, has a good industrial application prospect, and has very important significance in metal organic catalysis.
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Paragraph 0075-0084; 0087-0088
(2021/09/15)
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- Encapsulated liquid nano-droplets for efficient and selective biphasic hydroformylation of long-chain alkenes
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Aqueous nano-droplets of homogeneous Rh-TPPTS catalyst encapsulated within the cavity of hollow silica nanospheres were fabricated for biphasic hydroformylation of long-chain alkenes, which showed significant reaction rate enhancement effects and improved aldehyde selectivity.
- Zhang, Xiaoli,Wei, Juan,Zhang, Xiaoming
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supporting information
p. 14134 - 14138
(2019/09/18)
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- CYCLIC PEPTIDE ANTIBIOTICS
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Provided herein are antibacterial compounds, wherein the compounds in some embodiments have broad spectrum bioactivity. In various embodiments, the compounds act by inhibition of lipoprotein signal peptidase II (LspA), a key protein in bacteria. Pharmaceutical compositions and methods for treatment using the compounds described herein are also provided.
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- Rhodium-Complex-Catalyzed Hydroformylation of Olefins with CO2and Hydrosilane
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A rhodium-catalyzed one-pot hydroformylation of olefins with CO2, hydrosilane, and H2has been developed that affords the aldehydes in good chemoselectivities at low catalyst loading. Mechanistic studies indicate that the transformation is likely to proceed through a tandem sequence of poly(methylhydrosiloxane) (PMHS) mediated CO2reduction to CO and a conventional rhodium-catalyzed hydroformylation with CO/H2. The hydrosilylane-mediated reduction of CO2in preference to aldehydes was found to be crucial for the selective formation of aldehydes under the reaction conditions.
- Ren, Xinyi,Zheng, Zhiyao,Zhang, Lei,Wang, Zheng,Xia, Chungu,Ding, Kuiling
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supporting information
p. 310 - 313
(2016/12/30)
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- Rhodium nanoparticles as precursors for the preparation of an efficient and recyclable hydroformylation catalyst
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Despite all the advances in the application of nanoparticle (NP) catalysts, they have received little attention in relation to the hydroformylation reaction. Herein, we present the preparation of a hydroformylation catalyst through the immobilization of air-stable rhodium NPs onto a magnetic support functionalized with chelating phosphine ligands, which serves as an alternative to air-sensitive precursors. The catalyst was active in hydroformylation and could be used in successive reactions with negligible metal leaching. The interaction between the rhodium NPs and the diphenylphosphine ligand was evidenced by an enhancement in the Raman spectrum of the ligand. Changes occurred in the Raman spectrum of the catalyst recovered after the reaction, which suggests that the rhodium NPs are precursors of active molecular species that are formed in situ. The supported catalyst was active for successive reactions even after it was exposed to air during the recycling runs and was easily recovered through magnetic separation. Long live the catalyst! The heterogenization of rhodium catalysts onto a magnetic support and recovery without loss of metal, reactivity, and selectivity is discussed. Rhodium nanoparticles are used as catalyst precursors, and the active species are studied by using Raman spectroscopy.
- Garcia, Marco A. S.,Oliveira, Kelley C. B.,Costa, Jean C. S.,Corio, Paola,Gusevskaya, Elena V.,Dos Santos, Eduardo N.,Rossi, Liane M.
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p. 1566 - 1572
(2015/05/27)
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- Rhodium-containing hypercross-linked polystyrene as a heterogeneous catalyst for the hydroformylation of olefins in supercritical carbon dioxide
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A simple procedure for the incorporation of rhodium nanoparticles into a hypercross-linked polystyrene matrix is developed. The prepared heterogeneous catalyst shows high activity in the hydroformylation of olefins in supercritical carbon dioxide, and can be recycled six times without any noticeable decrease in productivity.
- Lyubimov, Sergey E.,Rastorguev, Eugenie A.,Lubentsova, Kseniya I.,Korlyukov, Alexander A.,Davankov, Vadim A.
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p. 1116 - 1119
(2013/04/10)
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- Stable fluorophosphines: Predicted and realized ligands for catalysis
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Ligand maps lead to treasure! The activity of complexes of fluorophosphines (R2PF) in catalytic hydroformylation and hydrocyanation is predicted from a ligand map. However, the instability of R2PF to disproportionation is well-documented. Examples of R2PF ligands (see scheme) are described that are stabilized to such an extent that they can be used in catalysis and are shown to be highly effective.
- Fey, Natalie,Garland, Michael,Hopewell, Jonathan P.,McMullin, Claire L.,Mastroianni, Sergio,Orpen, A. Guy,Pringle, Paul G.
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supporting information; experimental part
p. 118 - 122
(2012/03/26)
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- Pyrazoles as ligands for the Rh-catalyzed hydroformylation of alkenes in supercritical carbon dioxide
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Activity of pyrazole ligands in hydroformylation of a number of unsaturated terminal substrates in supercritical carbon dioxide (scCO2) in the presence of Rh-catalyst was studied. The ligands without free NH group at position 1 of the pyrazole ring were found to be active. The use of scCO 2 as the reaction medium served to reach a higher conversion and regioselectivity of hydroformylation as compared to those in toluene.
- Lyubimov,Rastorguev,Davankov
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p. 2356 - 2359
(2013/10/01)
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- Coordination studies on supramolecular chiral ligands and application in asymmetric hydroformylation
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In this study we introduce a series of monodentate pyridine-based ligands for which the phosphorus coordination mode to rhodium can be controlled by the binding of ZnII-templates to the pyridyl group. A series of monodentate phosphoroamidite and phosphite ligands have been prepared and studied under hydroformylation conditions by in situ high-pressure NMR and IR techniques. These studies reveal the exclusive formation of rhodium hydride complexes in which the phosphorus atom of the ligand resides in an axial position, trans to the hydride, but only after addition of Zn II-template. In the absence of these templates the usual mono-coordinated rhodium hydrido complexes are formed, with the phosphorus ligated in the equatorial plane, cis to the hydride. The catalytic performance of these complexes is evaluated in asymmetric hydroformylation of unfunctionalised internal alkenes in which the supramolecular change is reflected in higher activity and selectivity.
- Bellini, Rosalba,Reek, Joost N. H.
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supporting information; experimental part
p. 7091 - 7099
(2012/07/27)
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- Self-assembly of a confined rhodium catalyst for asymmetric hydroformylation of unfunctionalized internal alkenes
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A chiral supramolecular ligand has been assembled and applied to the rhodium-catalyzed asymmetric hydroformylation of unfunctionalized internal alkenes. Spatial confinement of the metal center within a chiral pocket results in reversed regioselectivity and remarkable enantioselectivities.
- Gadzikwa, Tendai,Bellini, Rosalba,Dekker, Henk L.,Reek, Joost N. H.
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supporting information; experimental part
p. 2860 - 2863
(2012/03/26)
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- The use of carboranylphosphite ligands in Rh-catalyzed hydroformylation of alkenes in supercritical carbon dioxide
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Novel carborane-containing phosphites were synthesized. The efficiency of the ligands was tested in the Rh-catalyzed hydroformylation of styrene, hept-1-ene, and oct-1-ene in supercritical carbon dioxide (scCO2) and toluene. The use of scCO2 as the reaction medium allows one to attain higher conversions and regioselectivities compared to toluene.
- Lyubimov,Petrovskii,Rastorguev,Verbitskaya,Kalinin,Davankov
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experimental part
p. 2074 - 2077
(2012/09/07)
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- Supramolecular control of ligand coordination and implications in hydroformylation reactions
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The coordination mode of a monodentate phosphoroamidite ligand in a rhodium complex can be switched from equatorial to axial by a unique supramolecular pseudo encapsulation (see scheme). The axial complex has higher activity and selectivity in the challenging asymmetric hydroformylation of internal alkenes. Copyright
- Bellini, Rosalba,Chikkali, Samir H.,Berthon-Gelloz, Guillaume,Reek, Joost N. H.
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supporting information; experimental part
p. 7342 - 7345
(2011/10/04)
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- Efficient platinum(II) catalyzed hydroformylation reaction in water: Unusual product distribution in micellar media
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The hydroformylation of a variety of terminal and internal alkenes is efficiently performed by cationic platinum triflate complexes of the type [P2Pt(H2O)2](OTf)2 under mild conditions in an aqueous micellar medium. The use of surfactants is essential to ensure dissolution of the catalyst and substrate in water with catalysts being positioned on the anionic surface of the micelles. Aldehydes are obtained with linear to branched ratios up to >99:1. With styrene derivatives also the corresponding benzaldehydes are formed. The catalyst can be separated by extraction of the organic products with hexane and recycled for at least four times with only a modest loss of activity and no effect on selectivity.
- Gottardo, Marina,Scarso, Alessandro,Paganelli, Stefano,Strukul, Giorgio
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experimental part
p. 2251 - 2262
(2010/12/25)
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- Self-neutralizing in situ acidic CO2/H2O system for aerobic oxidation of alcohols catalyzed by TEMPO functionalized imidazolium Salt/NaNO2
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(Chemical Equation Presented) A reversible in situ acidic catalytic system comprising recyclable TEMPO functionalized imidazolium salt ([Imim-TEMPO][Cl])/ NaNO2/CO2/H2O was developed for selective transformation of a series of aliphatic, allylic, heterocyclic, and benzylic alcohols to the respective carbonyl compounds. Notably, the system avoids any conventional acid and can eliminate unwanted byproducts, facilitate reaction, ease separation of the catalyst and product, and also provide a safe environment for oxidation involving oxygen gas.
- Miao, Cheng-Xia,He, Liang-Nian,Wang, Jing-Lun,Wu, Fang
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experimental part
p. 257 - 260
(2010/04/06)
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- Coprecipitated gold-trieobalt tetraoxide catalyst for heterogeneous hydroformylation of oleflns
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The combination of gold (Au0) and tricobalt tetraoxide (CO 3O4) prepared by coprecipitation gives high-performance heterogeneous catalysts for hydroformylation reaction with selectivity above 85% in desired aldehydes, alth
- Liu, Xiaohao,Haruta, Masatake,Tokunaga, Makoto
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scheme or table
p. 1290 - 1291
(2009/12/03)
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- Hydroformylation of olefins catalyzed by rhodium complexes with phosphinitecalix[4]arenes
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Hydroformylation of alkenes with various carbon chain lengths and arylalkenes in the presence of the catalytic system consisting of Rh(acac)(CO)2 and phosphinitecalix[4]arenes was studied. The influence of the P/Rh and substrate/catalyst ratios, temperature, and pressure on the process and the product composition was examined.
- Karakhanov,Kardasheva,Runova,Terenina,Shadrova
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p. 340 - 344
(2008/09/17)
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- Rhodium thiolate hydroformylation complexes tethered to delamellated γ-zirconium phosphate
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Rhodium thiolate complexes intercalated in crystalline γ-zirconium phosphate or tethered to SiO2-modified γ-zirconium phosphate have been synthesised. It was observed that the addition of a solution of organic silicates to a colloidal suspension of γ-zirconium phosphate yielded amorphous substrates, which displayed very high specific areas (160-650 m2 g-1). Incorporation of a mercaptocarbonyl rhodium complex resulted in a highly selective and active catalyst precursor for the hydroformylation of 1-heptene in the liquid phase. Elemental analysis and photoelectron spectroscopy of the fresh and used samples revealed that some metal leaching occurs during the reaction, this being mainly confined to the outer layers of the solid particles. This observation, together with the high selectivity towards linear aldehydes, makes SiO2-modified γ-zirconium phosphate a good support candidate for immobilised Rh catalysts. Spectroscopic data obtained from the crystalline precursor and also from the amorphous catalyst showed that the interaction between the rhodium complex and the acid support was achieved via hydrogen bonds, forming NH groups.
- Rojas,Murcia-Mascaros,Terreros,Garcia Fierro
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p. 1430 - 1437
(2007/10/03)
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- Chemoenzymatic deracemization of (±)-2,2-disubstituted oxiranes
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The preparation of vicinal diols in up to 98% e.e. and 98% yield from the corresponding (±)-2,2-disubstituted epoxides was achieved via an enantioconvergent two-step hydrolysis: Thus, enantioselective enzymatic hydrolysis of the (S)-epoxide proceeded with retention of configuration furnishing the corresponding (S)-diol. In a subsequent step, the remaining (R)-oxirane was hydrolyzed during workup under acid catalysis with complete inversion of configuration yielding the (5)-diol. A detailed study of the latter reaction revealed that the experimental conditions have to be carefully chosen with respect to (i) nature of the acid, (ii) the solvent, and (iii) its water content to avoid racemization.
- Orru, Romano V. A.,Mayer, Sandra F.,Kroutil, Wolfgang,Faber, Kurt
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p. 859 - 874
(2007/10/03)
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- Rhodium(I) fluorothiolate complexes as hydroformylation catalyst precursors. Crystal structure of two polymorphs of trans-[Rh(SC6F5) (CO) (PPh3) 2]
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The perfluorothiolate dinuclear compounds [Rh( μ,-SC6F5)(COD)]2 1 and [Rh( μ-SC6F5)(CO)2]2 2 react with PPh3 to give monomeric and dimeric complexes, the particular product depending upon the PR3/Rh ratio and reaction conditions. Reaction of 2 with 2 moles of PPh3 renders cis-7 and trans-[Rh( μ-SC6F5)((CO)(PPh3)]2 8, while with 4 moles of PPh3 trans[Rh(SC6F5)(CO)(PPh3)2]10a is obtained. This latter product can otherwise be prepared by Cl metathesis from trans-[RhCl(CO(PPh3)2] in toluene. This same reaction in dichloromethane however yields the cis isomer 10b. When a larger excess of PPh3 is used, a mixture of compounds 11a and 11b is formed. An X-ray crystal structure study shows trans[Rh(SC6F5)(CO)(PPh3)2] to exit as two polymorphs. 11a crystallises in the space group P21/n of the monoclinic system with a = 12.489(1), b= 15.430(5), c= 19.719(1) A, α = γ = 90, β = 92.84(1)°, and 11b is triclinic, space group P1 with a =9.764(2), b= 12.197(6), c= 17.880 A, α = 100.18(5), β = 101.92(2), γ = 113.61(2)°. Both PPh3 ligands are mutually trans and the difference in v(CO) stretching frequencies, 1989 and 1939 cm-1, can be explained in terms of o-phenyl H. . . CO interactions in the latter. The [Rh( μ-SC6F5)(COD)]2 1 and [Rh( μ-SC6F5)(CO)2]2 2/nPPh3 systems have been studied as catalyst precursors for the hydroformylation of 1-heptene in toluene at 30 bar and 343 K. Selectivity towards the linear aldehyde is enhanced when dimeric complexes are used.
- Fierro,Martinez-Ripoll,Merchan,Rodriguez,Terreros,Torrens,Vivar-Cerrato
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p. 243 - 255
(2007/10/03)
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- Polymer-supported Chain Homologation
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Addition of hept-1-ene to a suspension of polystyrene-bound forms of hydridocarbonyltris(triphenylphosphine)rhodium(I) and methylenetriphenylphosphorane in tetrahydrofuran, under a hydrogen/carbon monoxide atmosphere (60 deg C; 120 lb in-2), produces 2-methylheptanal (10percent), n-octanal (45percent), n-decanal (12percent), n-dodecanal (2percent), and n-tetradecanal (0.3percent) as major products.
- Regen, Steven L.,Kodomari, Mitsuo
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p. 1428 - 1429
(2007/10/02)
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- PHENYLTHIOMETHYLTRIMETHYLSILANE: A NEW FORMYL ANION SYNTHON
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α-Phenylthioalkyltrimethylsilanes, readily prepared by the alkylation of phenylthiomethyltrimethylsilane with alkyl halides or epoxides, can be converted to O-trimethylsilyl hemithioacetals via a Sila-Pummerer Rearrangement of the corresponding sulfoxides.The O-trimethylsilyl hemithioacetals are readily hydrolyzed to aldehydes.
- Kocienski, Philiph J.
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p. 1559 - 1562
(2007/10/02)
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- ACTION DES DIALKYLCUPRATES DE LITHIUM SUR LES ALDEHYDES α,β-ETHYLENIQUES
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Nearly exclusive 1-4 addition products are obtained by action of lithium dialkylcuprates with α,β-ethylenic aldehydes.Non polar solvents and low temperatures favor this reaction.Only α,β-ethylenic aldehydes having a trisubstituted double bond give a relatively important proportion of 1-2 addition product.
- Chuit, C.,Foulon, J. P.,Normant, J. F.
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p. 2305 - 2310
(2007/10/02)
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