- Role of acid in precursor conversion during InP quantum dot synthesis
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We have studied the speciation of P(SiMe3)3 during the synthesis of colloidal InP quantum dots in the presence of proton sources. Using 31P NMR spectroscopy, we show H3-nP(SiMe 3)n formation on exposure of P(SiMe3) 3 to a variety of protic reagents including water, methanol, and carboxylic acid, corroborating observations of P(SiMe3)3 speciation during the hot injection synthesis of InP QDs. Quantitative UV-vis comparisons between InP growth from P(SiMe3)3 and HP(SiMe3)2 show unambiguously that when total H +-content is accounted for, particle size, size dispersity, and concentration are indistinguishable for these two reagents. The dual role of myristic acid in P-Si bond cleavage and as a source of the myristate anion, an essential component of the quantum dot surface, is interrogated using tetrabutylammonium myristate, confirming that it is the protons that are responsible for increased quantum dot polydispersity. Together these data support the existence of a competing acid-catalyzed pathway in the conversion of P(SiMe3)3 to InP and demonstrate its impact. By preventing a constant solute supply and affecting the concentration of quantum dot surfactant over the course of the reaction, the existence of competing precursor conversion pathways is detrimental to formation of monodisperse colloids, explaining much of the irreproducibility in InP quantum dot syntheses to date.
- Gary, Dylan C.,Cossairt, Brandi M.
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Read Online
- A Simple Method for the Preparation of Tris(trimethylsilyl)phosphine
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Tris(trimethylsilyl)phosphine is prepared in good yield by the reation of piperidinodichlorophosphine with lithium and chlorotrimethylsilane in boiling tetrahydrofuran.
- Niecke, E.,Westermann, H.
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- Synthesis and X-ray crystal structure of novel tetramethylphosphonium dichlorodimethylaluminate
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The reaction of tris(trimethylsilyl)phosphine with dimethylaluminum chloride in 1,2-dimethoxyethane (monoglyme) displays an important role as building blocks that results in the production of novel tetramethyl phosphonium dichlorodimethylaluminate and the already known dimer compound (bis(2,2-methoxy-ethanolato-O,O′)-tetramethyl-di-aluminum). The newly formed tetramethyl phosphonium dichlorodimethylaluminate [(CH3)4P]+[(CH3)2AlCl2]? crystallizes in the monoclinic space group P21/c, having unit cell with lattice constants a = 7.522, b = 11.644, c = 14.841 ?, and β = 99.32° includes four formula units. The mean values of the bond lengths are P-C 1.787 ?, Al-Cl 2.224 ?, and Al-C 1.966 ?. Both phosphorus and aluminum are tetrahedrally surrounded in organophosphonium-based cations and organoaluminium-based anions. The geometry of the dichlorodimethylaluminate anion shows a distorted tetrahedron.
- Bani-Fwaz, Mutasem Z.
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Read Online
- 1-Heteroakylation of tris(trimethylsilyl)phosphine
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The 1-heteroalkylation of the tris-(trimethylsilyl)phosphine was thoroughly investigated using heterosubstituted methylamines, chloromethyl alkyl ethers, methyl chloroformate, paraformaldehyde, and dialkylformamides. Convenient methods for the synthesis of tris(dialkylaminomethyl)phosphines, tris(alkoxymethyl)phosphines, tris(methoxycarbonyl) phosphine, and several phosphaethylenes were proposed on the basis of the 1-heteroalkylation of tris(trimethylsilyl)phosphine as a valuable synthon.
- Prishchenko, Andrey A.,Livantsov, Mikhail V.,Novikova, Olga P.,Livantsova, Ludmila I.,Petrosyan, Valery S.
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- A stable enol in small ring systems: Clear differentiation between penta- and tri-valency of phosphorus atoms
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The first stable enols in 1,2-dihydrophosphetes 6 and 10 were synthesized and structurally characterized with intermolecular hydrogen bonds to phosphoryl groups in 10-membered dimeric structures; in contrast, trivalent analogue 9 exists in keto-form, where such stabilization by hydrogen bonds is not feasible. The Royal Society of Chemistry.
- Ionkin, Alex S.,Marshall, William J.,Fish, Brian M.,Schiffhauer, Matthew F.,McEwen, Charles N.
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- Simple conversion of trisodium phosphide, Na3P, into silyl- and cyanophosphides and the structure of a terminal silver phosphide
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A reaction of trisodium phosphide (Na3P) with chlorosilanes allows for simple derivatization into silyl- and cyano-substituted phosphanide species which were compared with each other. The recently discovered cyano(triphenylsilyl)phosphanide shows unique coordination properties compared to bis(silyl)phosphides.
- Grützmacher, Hansj?rg,Le Corre, Grégoire
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supporting information
p. 3497 - 3501
(2022/03/14)
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- Method for producing InP quantum dot precursors and method for producing InP quantum dots
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The present invention pertains to a method for producing InP quantum dot precursors from a phosphorus source and an indium source, wherein a silylphosphine compound represented by general formula (1), which contains a compound represented by general formula (2) in an amount of 0.3 mol% or less, is used as the phosphorus source. Further, the present invention provides a method for producing InP quantum dots, said method comprising heating the InP quantum dot precursors at a temperature of 200-350 DEG C inclusive to thereby give InP quantum dots. (R is as defined in the description.).
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Paragraph 0122; 0125-0126
(2021/02/05)
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- Exploration of Novel α,ω-Substituted Diphosphatrisilanes by Combining Experimental Methods and DFT Calculations
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The novel diphosphatrisilanes {(R2P-Si(SiMe3)2-)2-SiMe2} [R = Ph, H] and the cyclophosphatrisilabutanes {R–PSi3} [R = H, SiMe3] have been prepared via salt metathesis reactions between phosphanides and 2,4-dihalogenated pentasilanes and characterized via NMR spectroscopy. The experimental results were supported by DFT calculations. Although P–Si bond formation was observed in all cases, the outcome of the reactions varied depending on the nature of ligands on the phosphanides, forming either linear diphosphatrisilanes or cyclic phosphatrisilacyclobutanes. DFT studies were performed to get a better understanding of the reactions. The precursor silanes were fully characterized using NMR spectroscopy and single-crystal X-ray diffraction and offer interesting building blocks. In addition, a modified route for the synthesis of P(TMS)3 was successfully carried out, achieving high yields of up to 73 %, circumventing the use of white phosphorus and phosphine gas during the reaction.
- Weinberger, Gernot P.,Sommer, Florian,Torvisco, Ana,Fischer, Roland C.,Flock, Michaela
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p. 3778 - 3785
(2020/09/09)
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- PROCESS FOR PRODUCING SILYL PHOSPHINE COMPOUND AND SILYL PHOSPHINE COMPOUND
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The process for producing a silyl phosphine compound of the present invention comprises a first step of mixing a solvent having a relative dielectric constant of not more than 4, a basic compound, a silylating agent and phosphine to obtain a solution containing a silyl phosphine compound, a second step of removing the solvent from the solution containing a silyl phosphine compound to obtain a concentrated solution of a silyl phosphine compound, and a third step of distilling the concentrated solution of a silyl phosphine compound to obtain the silyl phosphine compound. The silyl phosphine compound of the present invention is a silyl phosphine compound represented by the following general formula (1), wherein a content of a compound represented by the following general formula (2) is not more than 0.5 mol %. (For explanatory notes of the formulas, see the specification.)
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Paragraph 0081-0087; 0096-0101; 0103-0107; 0109-0113
(2019/09/06)
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- Synthetic studies on a series of functionalized pyrylium salts, 4-chloro- and 4-bromophosphinines
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A series of new pyrylium salts that bear sulfonate and phosphonate groups were obtained from the reactions between 2,6-diphenyl-4H-pyran-4-one, sulfonic anhydride, and chlorophosphates, and analyzed spectroscopically. Furthermore, treatment of 2,6-diphenyl-4H-pyran-4-one with phosphoryl chloride or bromide afforded the corresponding 4-chloro- and 4-bromopyrylium tetrafluoroborates in good yield. Subsequently, the synthesis of the corresponding 4-chloro- and 4-bromophosphinines was accomplished by treating the respective chloro- and bromopyrylium tetrafluoroborates with tris(trimethylsilyl)phosphine.
- Nagahora, Noriyoshi,Tokumaru, Hiroshi,Ikaga, Shinpei,Hanada, Takuya,Shioji, Kosei,Okuma, Kentaro
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p. 1880 - 1887
(2018/03/07)
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- Mono- and dinuclear tetraphosphabutadiene ferrate anions
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Reduction of [CpArFe(μ-Br)]2 (1, CpAr = C5(C6H4-4-Et)5) by potassium napthalenide, followed by the addition of white phosphorus, affords [K(18-c-6){CpArFe(η4-P4)}] (2, 18-c-6 = [18]crown-6), which features a planar cyclo-P42- ligand. The related diiron complex [Na2(THF)5(CpArFe)2(μ,η4:4-P4)] (3) was obtained by reducing 1 with sodium amalgam in the presence of P4. Protonation of 3 affords [Na(THF)3][(CpArFe)2(μ,η4:4-P4)(H)] (4), while the reaction of 3 with trimethylchlorosilane gives the nortricyclane compound P7(SiMe3)3 as the main product.
- Chakraborty, Uttam,Leitl, Julia,Mühldorf, Bernd,Bodensteiner, Michael,Pelties, Stefan,Wolf, Robert
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supporting information
p. 3693 - 3697
(2018/03/21)
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- Synthesis, crystal structures, and quantum chemical calculations of Novel Phosphonium Salt-1,5-diphospha-3-phosphonia-tricyclo pentane cations
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This work deals with reactions between the kinetically stable 2-tert-butyl-1λ3-phospha-alkyne, tBu-C[tbnd]P, and various halodiorganylphosphines (X = Cl, Br). The isolated ionic salts with the 2,4-di-tert-butyl-3,3-diorganyl-1λ3,5λ3-diphospha-3-phosphonia-tricyclo[2.1.0.02,5]pentane cations, [R2C2tBu2P3]⊕ (R = ethyl, isopropyl, methyl, phenyl), were characterized by spectroscopic methods; additionally, the results of X-ray structure analyses were confirmed by quantum chemical calculations with Gaussian 03 program which were performed on the hydrogen substituted phosphonium and phosphenium cations in order to ascertain optimized structural data and relative energies for different isomers. As for the phosphonium cation ([H2P(CH)2P2]⊕) generated from our work the conventional trigonal bipyramidal framework of point group C2v represents the absolute minimum on the potential energy surface. To our surprise this situation is followed by a second one which has to be attributed to the so-called housene structure of point group C1 showing a somewhat higher energy value + 77.9 kJ/mol. Quite a reverse situation is encountered for the phosphenium cation [P(CH)2P2]⊕. Here the pseudo square-based pyramidal nido structure of point group C2v known from Russell's tetrachloroaluminate(III) compound is found to be the only minimum on the potential energy surface. A phosphenium cation with a trigonal bipyramidal framework of point group C2v is higher in energy by only 35.7 kJ/mol, but due to one imaginary frequency it has to be considered the structure of a transition state. The opened housene structure corresponds neither to a minimum nor to a saddle point on the potential energy surface. In the pseudo square-based pyramidal nido structure (point group C2v) of the phosphenium cation [P(CH)2P2]⊕ the s-orbital and all p-orbitals of the apical four-coordinate phosphorus atom are used to form two P–C and two P–P bonds. Further addition of two hydrogen atoms to entail the phosphonium cation [H2P(CH)2P2]⊕ of point group symmetry C2 not only increases the coordination number of the apical phosphorus atom to six but also requires two electrons and two orbitals for P–H bonding. These are no longer available to the bonding system within the nido structure; as a consequence, its energy increases to +246.6 kJ/mol and the cation rearranges to give the conventional structure of ours.
- Bani-Fwaz, Mutasem Z.,Fazary, Ahmed E.,Becker, Gerd
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supporting information
p. 51 - 65
(2017/06/07)
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- METHOD FOR PREPARING TRIS(TRIALKYLSILYL)PHOSPHINE
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The present invention relates to a method for preparing a tris(trialkylsilyl)phosphine in high yield and high purity with safety and no risk of fire or explosion.
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Paragraph 0052-0057; 0064-0066-0078
(2017/12/27)
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- Synthetic, Structural, and Spectroscopic Characterization of a Novel Family of High-Spin Iron(II) [(β-Diketiminate)(phosphanylphosphido)] Complexes
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This work describes a series of iron(II) phosphanylphosphido complexes. These compounds were obtained by reacting lithiated diphosphanes R2PP(SiMe3)Li (R = t-Bu, i-Pr) with an iron(II) β-diketiminate complex, [LFe(μ2-Cl)2Li(DME)2] (1), where DME = 1,2-dimethoxyethane and L = Dippnacnac (β-diketiminate). While the reaction of 1 with t-Bu2PP(SiMe3)Li yields [LFe(η1-Me3SiPP-t-Bu2)] (2), that of 1 with equimolar amounts of i-Pr2PP(SiMe3)Li, in DME, leads to [LFe(η2-i-Pr2PPSiMe3)] (3). In contrast, the reaction of 1 with (i-Pr2N)2PP(SiMe3)Li provides not an iron-containing complex but 1-[(diisopropylamino)phosphine]-2,4-bis(diisopropylamino)-3-(trimethylsilyl)tetraphosphetane (4). The structures of 2-4 were determined using diffractometry. Thus, 2 exhibits a three-coordinate iron site and 3 a four-coordinate iron site. The increase in the coordination number is induced by the change from an anticlinal to a synclinal conformation of the phoshpanylphosphido ligands. The electronic structures of 2 and 3 were assessed through a combined field-dependent 57Fe M?ssbauer and high-frequency and -field electron paramagnetic resonance spectroscopic investigation in conjunction with analysis of their magnetic susceptibility and magnetization data. These studies revealed two high-spin iron(II) sites with S = 2 ground states that have different properties. While 2 exhibits a zero-field splitting described by a positive D parameter (D = +17.4 cm-1 E/D = 0.11) for 3, this parameter is negative [D = ?25(5) cm-1 E/D = 0.15(5)]. Density functional theory (DFT) and time-dependent DFT (TDDFT) calculations provide insights into the origin of these differences and allow us to rationalize the fine and hyperfine structure parameters of 2 and 3. Thus, for 2, the spin-orbit coupling mixes a z2-type ground state with two low-lying {xz/yz} orbital states. These interactions lead to an easy plane of magnetization, which is essentially parallel to the plane defined by the N-Fe-N atoms. For 3, we find a yz-type ground state that is strongly mixed with a low-lying z2-type orbital state. In this case, the spin-orbit interaction leads to a partial unquenching of the orbital momentum along the x axis, that is, to an easy axis of magnetization oriented roughly along the Fe-P bond of the phosphido moiety.
- Grubba, Rafal,Kaniewska, Kinga,Ponikiewski, Lukasz,Cristóv?o, Beata,Ferenc, Wieslawa,Dragulescu-Andrasi, Alina,Krzystek,Stoian, Sebastian A.,Pikies, Jerzy
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p. 11030 - 11042
(2017/09/25)
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- 2,4,6-Triphenylphosphinine and 2,4,6-triphenylposphabarrelene revisited: Synthesis, reactivity and coordination chemistry
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The synthesis of 2,4,6-triphenylphosphinine has been revisited and a general protocol for the preparation of such low-coordinate phosphorus compounds in good to excellent yields could be established. This allows to investigate several aspects of the chemistry of 2,4,6-triarylphosphinine, such as the reaction with in situ generated benzyne to give 2,4,6-triphenylphosphabarrelene. The corresponding 2,4,6-triphenylphosphabarrelene-selenide could be characterized crystallographically for the first time and the structural and electronic properties of this cage-compound in comparison to classical triarylphosphines could be evaluated. Moreover, [(L)W(CO)5)] complexes of both 2,4,6-triphenylphosphinine and 2,4,6-triphenylphosphabarrelene were prepared and characterized by means of X-ray crystallography. This allowed for the first time a direct structural comparison of these related phosphorus compounds, coordinated to the same metal fragment.
- Rigo,Sklorz,Hatje,Noack,Weber,Wiecko,Müller
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p. 2218 - 2226
(2016/02/09)
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- Formation of polyphosphorus ligands mediated by zirconium and hafnium complexes
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The reactions of R2P-P(SiMe3)Li (R = tBu, iPr, iPr2N) with [Cp2MCl 2] (M = Zr, Hf), [Cp*z.ast;CpZrCl2] and [CpZrCl 3] yielded polyphosphorus (mainly hexaphosphorus) compounds which can be viewed as intermediates between R2P-P(SiMe3)Li and derivatives of 1,2,3,4-tetraphosphabicyclo[1.1.0] butane. Thus R 2P-P(SiMe3)Li can act as a building block for the formation of the P2 ligand and the R2P-P(P2) and R2P-P(P2)P-PR2 moieties. Solid state structures of zirconium(IV) and hafnium(IV) complexes with R2P- P(P2) and R2P-P(P2)P-PR2 ligands were established by X-ray studies.
- Wi?niewska, Aleksandra,?apczuk-Krygier, Agnieszka,Baranowska, Katarzyna,Chojnacki, Jaros?aw,Matern, Eberhard,Pikies, Jerzy,Grubba, Rafa?
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- Syntheses and structures of the first terminal phosphanylphosphido complex of hafnium [Cp2Hf(Cl){η1-(Me3Si)P- P(NEt2)2}] and the first zirconocene- phosphanylphosphinidene dimer [Cp2Zr{μ2-P-P(NEt 2)2}2ZrCp2]
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Reactions of (Et2N)2P-P(SiMe3)Li with [Cp2MCl2] (M = Zr, Hf) in toluene or pentane yield the related terminal phosphanylphosphido complexes [Cp2M(Cl) {η1-(Me3Si)P-P(NEt2)2}]. The solid state structure of [Cp2Hf(Cl){η1-(Me 3Si)P-P(NEt2)2}] was established by single crystal X-ray diffraction. The reaction of (Et2N)2P- P(SiMe3)Li with [Cp2ZrCl2] in THF or DME solutions leads to the formation of deep red crystals of the first neutral diamagnetic zirconocene-phosphanylphosphinidene dimer [Cp2Zr{μ 2-P-P(NEt2)2}2ZrCp2]. The molecular structure of this compound was confirmed by X-ray diffraction. The reactions of (R2N)2P-P(SiMe3)Li with [CpZrCl3] yield the related tetraphosphetanes R2NP(μ 2-PSiMe3)2PNR2, which apparently are formed as a result of a transfer of NR2 groups from a P atom to the Zr atom. The Royal Society of Chemistry 2011.
- Grubba, Rafal,Wisniewska, Aleksandra,Baranowska, Katarzyna,Matern, Eberhard,Pikies, Jerzy
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experimental part
p. 2017 - 2024
(2011/04/16)
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- Radical synthesis of trialkyl, triaryl, trisilyl and tristannyl phosphines from P4
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A reaction scheme has been devised according to 3 RX + 3 Ti(iii) + 0.25 P4 → PR3 + 3 XTi(iv), wherein RX = PhBr, CyBr, Me3SiI or Ph3SnCl, with contrasting results in the case of more hindered RX. The scheme accomplishes the direct radical functionalization of white phosphorus without the intermediacy of PCl3.
- Cossairt, Brandi M.,Cummins, Christopher C.
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supporting information; experimental part
p. 1533 - 1536
(2010/10/03)
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- Reactions of R2P-P(SiMe3)Li with [(R′ 3P)2PtCl2]. A general and efficient entry to phosphanylphosphinidene complexes of platinum. Syntheses and structures of [(η2-P=PiPr2
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Full Title: Reactions of R2P-P(SiMe3)Li with [(R′ 3P)2PtCl2]. A general and efficient entry to phosphanylphosphinidene complexes of platinum. Syntheses and structures of [(η2-P=Pi/sup
- Domanska-Babul, Wioleta,Chojnacki, Jaroslaw,Matern, Eberhard,Pikies, Jerzy
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body text
p. 146 - 151
(2009/04/10)
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- A highly tunable family of chiral bisphospholanes for Rh-catalyzed enantioselective hydrogenation reactions
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A set of 16 new and closely related bisphospholane ligands have been prepared by using a highly flexible and convergent approach. Each synthesis can be performed on an industrially relevant scale. The bisphosphines differ in the nature of the bridge connecting both phospholane units. Bridges are formed by three-, four-, five- and six-membered heterocyclic or alicyclic rings. Bisphospholanes and their Rh-precatalysts have been investigated by using results of theoretical calculations (DFT) and analytic measurements ( 31P and 103Rh NMR spectroscopy, X-ray structure analysis). The studies showed that catalysts based on ligands with maleic anhydride or maleimide bridges give constantly superior enantioselectivities in methanol as the solvent. This may account for optimised steric and electronic effects. However, by changing the solvent catalysts with other backbones can give rise to excellent results. This gives proof that simple correlations between steric and electronic properties and results in the enantioselective hydrogenation frequently claimed in literature are not general.
- Holz, Jens,Zayas, Odalys,Jiao, Haijun,Baumann, Wolfgang,Spannenberg, Anke,Monsees, Axel,Riermeier, Thomas H.,Almena, Juan,Kadyrov, Renat,Boerner, Armin
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p. 5001 - 5013
(2008/02/10)
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- Bis(bis(trimethylsilyl)phosphino)silan 2SiH2 und 1,2-Bis(bis(trimethylsilyl)phosphino)disilan 2
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The compounds H2Si2 and 2 were prepared and characterized by 29Si NMR, 31P NMR, IR and Raman spectroscopy.After thermolysis of these compounds no cyclic silylphosphanes could be detected in the reaction mixture, although this did contain P(SiMe3)3.
- Hassler, K.,Katzenbeisser, U.
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p. C18 - C20
(2007/10/02)
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- Synthesis and Structures of New 1,3,2,4-Diphosphadiboretanes
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Three methods have been devised to prepare new diphosphadiboretanes: a) Base-induced hydrogen halide elimination from (amino)phosphinoboron halides precursors, b) tris(trimethylsilyl)phosphane elimination from R2N-B2 intermediates prepared in situ from combination of R2N-B(Cl)-P(SiMe3)2 and LiP(SiMe3)2, and organylphosphane elimination from aminobis(organylphosphino)boranes R2N-B(PHR')2.The molecular structures of three new 1,3,2,4-diphosphadiboretanes (3, 4a, 4c) were determined by X-ray diffractometry.These are characterized by a planar four-membered B2P2 ring with the phosphorus substituents in trans positions.Their BP bomnds represent single bond distances.Experimental results are compared with MNDO III calculations which reveal a low barrier (ΔE = 5 kcal/mol) for the dimerization of the boraphosphane H2N-B=PMe to the diphospadiboretane (H2N-BPMe)2.
- Koelle, Peter,Linti, Gerald,Noeth, Heinrich,Wood, Gary L.,Narula, Chaitanya K.,Paine, Robert T.
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p. 871 - 880
(2007/10/02)
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- Transition Metal-Substituted Diphosphenes, XIII. - On the Synthesis of (ν5-C5Me5)(CO)(NO)Re-P=P-C6H2(tBu)3-(2,4,6) and (ν5-C5Me5)(CO)(NO)ReP=P-C6H2(tBu)3-(2,4,6)
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Compound (ν5-C5Me5)(CO)(NO)ReBr (3), generated from 5-C5Me5)(CO)2(NO)Re>BF4 and (Bu4N)Br, reacts with LiP(SiMe3)2 to give the disilylphosphido complex (ν5-C5Me5)(CO)(NO)ReP(SiMe3)2 (4).Complex 4 is converted into the diphosphenyl complex (ν5-C5Me5)(CO)(NO)Re-P=P-C6H2(tBu)3-(2,4,6) (5) by treatment with 2,4,6-(tBu)3C6H2PCl2.The reaction of 5, which is stable in solution, with Cr(CO)3 affords stable (ν5-C5Me5)(CO)(NO)ReP=P-C6H2(tBu)3-(2,4,6) (7).For comparison, the complexes (ν5-C5Me5(CO)(NO)MnP=P-C6H2(tBu)3-(2,4,6) (9) and (ν5-C5Me5)(CO)2 FeP=P-C6H2(tBu)3-(2,4,6) (10) were synthesized as well.Compound 10 was characterized by an X-ray structure analysis.
- Weber, Lothar,Meine, Georg,Boese, Roland,Blaeser, Dieter
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p. 853 - 858
(2007/10/02)
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- A new Type of Transition-Metal Dimer Based on a Hexaphosphine Ligand System: Co2(CO)4(eHTP)(2+) (eHTP = (Et2PCH2CH2)2PCH2P(CH2CH2PEt2)2)
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The synthesis and characterization of a new hexa-tert-phosphine ligand system, (Et2PCH2CH2)2PCH2P(CH2CH2PEt2)2, 1, is described.This ligand has the ability to both tris-chelate and bridge two transition metals, either in a closed-mode, M-M bonding geometry, or in an open-mode configuration in which the two metal atoms are 6-7 Angstroem apart.Reaction of 1 with 2 equiv of CoCl2 initially produces, in high yiels, the paramagnetic, binuclear, red-brown Co(II) compound, Co2Cl4(eHTP), 4, where eHTP = 1.An Extended X-ray Absorption Fine Structure (EXAFS) spectrum of 4 shows Co-P and Co-Cl bond distances in the 2.2-2.4 Angstroem region and no Co-Co contact distance less than 4.0 Angstroem, indicating that 4 is in an open-mode geometry.On standing, 4 dissociates two chloride ligands to form the green, paramagnetic Co2Cl2(eHTP)(2+) complex, 5, which precipitates out of the reaction mixture, either as the chloride or, if an extra equivalent of CoCl2 is used, the CoCl4(2-) salt.The EXAFS spectrum on the CoCl4(2-) salt of 5 is very similar to that of 4, indicating that 5 is also in an open-mode geometry.Reaction of 4 or 5 (alone or mixed) with H2/CO (33percent CO) and an extra equivalent of CoCl2 at 50 bar and 80 deg C forms, in high yields, the yellow-green, diamagnetic Co(I) binuclear carbonyl/eHTP complex, , 6a, which can be metathesized with aqueous NaPF6 to give the yellow PF6(1-) salt, 6b. 6 has been charactirized by 1H and 31P NMR, EXAFS, mass spectroscopy, IR, and a crystal structure.Crystals of 6b belong to the monoclinic space group C2/c, with unit cell parameters a = 26.464 (4) Angstroem, b = 12.562 (2) Angstroem, c = 14.380 (3) Angstroem, β = 99.04 (1) deg, V = 4721 (3) Angstroem3, and Z = 4.The structure was refined to give R = 0.070 and Rw = 0.106.The molucule lies on a 2-fold axis, passing through the bridging methylene group of the eHTP ligand.The complex has the central bis(phosphino)methane portion of the eHTP ligand adopting a unique inverted coordination geometry to give an open-mode complex with the two cobalt atoms separated by 6.697 (1) Angstroem.The cobalt atoms have a distorted trigonal-bipyramidal geometry with one carbonyl ligand and two terminal phosphorus atoms of the eHTP ligand in the equatorial plane.
- Askham, Fredric R.,Stanley, George G.,Marques, Edward C.
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p. 7423 - 7431
(2007/10/02)
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- Model Type Calculations of the Vibrational Spectra of Tris(trimethylsilyl)phosphane and Tris(triphenylsilyl)phosphane
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The vibrational spectra of Tris(trimethylsilyl)phosphane-d0 and -d27 as well as Tris(triphenylsilyl)phosphane are reported and assigned.A normal coordinate analysis has been performed.The resulting SiP valence force constants (190 and 200 N/m) are compared with the force constants of other silylphosphanes. - (Keywords: Force constants; Phosphanes; Silylphosphanes; Vibrational spectra)
- Hassler, K.
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p. 713 - 724
(2007/10/02)
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- Organometalphosphine-Substituted Transition Metal Complexes, XXVI Dicarbonyl Nitrosyl Organometal Phosphine Cobalt Complexes
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The reactions of tricarbonyl nitrosyl cobalt with tri-tert-butylphosphine, di(tert-butyl)-trimethylsilyl-, germyl-, stannylphosphine, tert-butyl-bis(trimethylsilyl)-, -(germyl)-, -(stannyl)phosphine, as well as with tris(trimethylsilyl)-, -(germyl)-, and -(stannyl)phosphine result in the elimination of one CO-ligand and the formation of corresponding dicarbonyl-nitrosyl-organometal phosphine cobalt complexes.The NMR spectra of the products are reported and discussed. - Keywords: Organometal Phosphines, Dicarbonyl-nitrosyl Cobalt Complexes, NMR Spectra
- Schumann, Herbert,Meissner, Manfred
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p. 594 - 598
(2007/10/02)
-