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  • Biochemistry and Biotechnology  (3,767)
  • Cell & Developmental Biology  (3,552)
  • Phosphorus
  • Synthetic methods
  • Wiley-Blackwell  (7,408)
  • American Meteorological Society
  • Blackwell Publishing Ltd
  • Springer Nature
  • 1995-1999  (5,986)
  • 1965-1969  (1,298)
  • 1915-1919  (124)
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  • Wiley-Blackwell  (7,408)
  • American Meteorological Society
  • Blackwell Publishing Ltd
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  • Springer  (51)
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  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 951-954 
    ISSN: 0009-2940
    Keywords: Phosphane-boranes ; Medium-sized rings ; Ring opening and closure ; Temperature-dependent NMR studies ; Phosphorus ; Boron ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A phosphane-borane (3) with the P-B bond integrated into a seven-membered ring was prepared from 4-pentenyl-diphenylphosphane (4) by hydroboration using 9-borabicyclononane (9-BBN). The product was confirmed to have a ring structure in the solid state by single crystal X-ray diffraction. The P-B distance of 2.057(2) Å is indicative of a standard donor-acceptor bond similar to the type found in homologous five- and six-membered rings. The room-temperature 31P-NMR signal of the compound in various solvents (δ ≈ - 15) is not compatible with the cyclic structure and suggests that ring opening occurs as the compound is dissolved. Variable-temperature NMR work corroborated this assumption, and the enthalpy of ring closure was determined to be ΔH = -30.5(4) kJmol-l. In CD2C12 at -90°C, δ31P is shifted to +3.5 ppm to low field, suggesting virtually complete ring closure under these conditions.
    Additional Material: 4 Ill.
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  • 2
    ISSN: 0009-2940
    Keywords: Bis(tetramethylipiperidino)aluminum halides ; Alkoxy((tetramethylpiperidino)aluminum halides ; 27Al-NMR spectra ; Aluminum ; Amides ; Synthetic methods ; Bridging ligands ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: N-Lithio-2,2,6,6-tetramethylpiperidine [Li(tmp)] reacts with AlX3 (X = Cl, Br) in diethyl ether/ n-hexane solution to generate the products of substitution and ether cleavage, [tmpAl(X)(μ-OEt)], (la, X = Cl; 1b, X = Br). However, when the reaction is allowed to proceed in n-hexane alone, an almost quantitative yield of compounds tmp2AlX (2a, X = Cl; 2b, X = Br; 2c, X = I) is obtained. According to 27AI-NMR spectroscopy, mass spectroscopy, cryoscopy, and X-ray crystal structure determinations, these compounds are monomeric in the solid state, in solution, and in the gas phase. 2b reacts with AgBF4 yielding the fluoride-bridged dimer (tmp2AlF), 2d, as shown by X-ray crystal structure determination.
    Additional Material: 3 Tab.
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 135-140 
    ISSN: 0009-2940
    Keywords: Synthesis ; Phosphorus ; Supersilyloligophosphides ; Crystal structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reaction of P4 in THF or DME with 2 R*Na (R* = SitBu3) at -78°C leads quantitatively to deep red THF or DME adducts of R*NaP-P=P-PNaR* (3). According to 31P NMR, the P4 skeleton 3 is cis-configurated. On the other hand, reaction of P4 in TBME with 2 R*Na at -78°C leads quantitatively to (R*NaP)4 (4), a [2+2] cycloadduct of 3, the Na4P8 skeleton of which according to X-ray structure analysis forms a double cube with four P atoms in the second layer and two P and two Na atoms in alternating positions in the first and in the third layer (the Na atoms are coordinated with donors). By resolving the THF adduct 3 in TBME (the TBME adduct of 4 in THF) the compound 4 (the compound 3) is rapidly formed under reversal of the P-P=P-P configuration by way of [2+2] cycloaddition (by way of [2+2] cycloreversion). 3 and 4 are sensitive to oxidation and to protolysis. With TCNE, 3 is oxidized to R*2P4 (bicyclic P4 skeleton), with CF3SO3H, 3 may be transformed into R*3P5Na2 X 4 THF or in (R*P3)3 and R*PH2.
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 299-305 
    ISSN: 0009-2940
    Keywords: Iodine ; Phosphorus ; Charge transfer ; NMR spectroscopy ; Raman spectroscopy ; Structure elucidation ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The solid-state and solution structures of Ph3P · I2 have been studied in detail by electronic, 31P{1H}-NMR and Raman spectroscopy as well as conductometric measurements. When 1 : 1 ratios of triphenylphosphane and diiodine are mixed in dichloroethane, the molecular adduct is shown to exist also in solution. On the basis of the overall results, this molecular adduct is best described as a charge-transfer complex of the donor I- with the acceptor Ph3PI+, rather than the charge-transfer complex of the donor Ph3P with the acceptor I2 or the ionic species [Ph3PI]I as previously proposed. When higher diiodine to triphenylphosphane ratios are used, the Ph3P · I2 adduct dissociates to give Ph3PI+ and I3- or I5- depending on the diiodine excess. Previously reported solution data, which were ascribed to the ionic form of the adduct, are instead in agreement with hydrolysis products (Ph3PO, PH3POH+) of the very reactive adduct, formed in the presence of traces of water.
    Additional Material: 7 Ill.
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  • 5
    ISSN: 0009-2940
    Keywords: Phosphorus ; Arsenic ; Germanium ; Inorganic heterocycles ; Metal amides ; Fluorinated ligands ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reactions of potassium Rf-amide [Rf = tris(trifluoromethyl)phenyl](2) with PCl3, AsC13, and GeC12 · dioxane yield new four-membered inorganic heterocycles [RfNPCl]2 (3), [RfNAsC1]2 (4), and [RfNGe]2 (5), respectively. On the other hand, the reaction of Rf-amide 2 with two equivalents of RfPCl2 leads to the formation of the imino-γ3-phosphane RfN=PRf (6) and the diamino-γ3-phosphane (RfNH)2PRf (7). The iminophosphane 6 reacts with Ni(CO)2(PPh3)2 and forms the complex [Ni(PPh3)2(RfN=PRf)] (9), in which the imino- phosphane coordinates to the metal through the phosphorus lone pair. Treatment of lithium amide 2 with transition metal chlorides ZnCl2 and FeCl2 yields the imido/amido spirocyclic metal derivatives 9 and 10, respectively. Compounds 3-10 have been extensively characterized by their analytical and mass, IR, and NMR (1H, 19F, and 31P) spectroscopy. Further, the molecular structures of all the compounds have been unambiguously determined by single-crystal X-ray diffraction studies. The diazadigermetidine 5 crystallizes in a fluorescent-yellow orthorhombic and a yellow monoclinic crystal modification. The results obtained reveal the role of Rf, group in stabilizing new multiple bonded systems and inorganic heterocycles. A skeletal rearrangment of the Rf ligand is observed in the reactions leading to compounds 9 and 10. Moreover, the preparation of compounds 9 and 10 indicates the limitation of the use of this ligand in the preparation of new metal-amide systems, especially where the metal atoms have a strong tendency for the formation of strong M—F bonds.
    Additional Material: 8 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1235-1240 
    ISSN: 0009-2940
    Keywords: Phosphorus ; Phase transitions ; Molecular crystal ; Crystal growth ; Low-temperature crystal structure ; Librational motion ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: White phosphorus occurs in three modifications. The α form, which exists at roomtemperature, transforms reversibly to the β form at -77°C. The α · β transformation may be strongly delayed. Quenching the α form to -185°C followed by slow warming results in an exothermic reactions with formation of the γ form which transforms into the β form at -120°C in an endothermic reaction. A transition β · γ is not observed. The γ form is characterized by its powder diagram. The structure of the β form is redetermined from a single crystal at -185°C (P., α = 547.88(5), b = 1078.62(11), c = 1096.16(11)pm, α= 94.285(8), β = 99.695(7), γ = 100.680(7)., V = 623.79(10) · 106 pm3, Z = 6 formula units per cell). The P4 molecules exhibit pronounced librational motion in spite of the low temperature of investigation. The arrangement of the centers of the tetrahedra corresponds to the atom positions in the γ-plutonium structure, which is discussed in relation to the bcc structure.
    Additional Material: 7 Ill.
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  • 7
    ISSN: 0009-2940
    Keywords: Boron ; Phosphorus ; Spiro compounds ; Cage compounds ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reactions of 1-lithio · DME-2,4-bis(dialkylamino)-l,3,2,4-diphosphadiboretanes (1a, 1b) with SiCl4 followed by dehydrohalogenation with tBuLi produce spirocyclic compounds [(R2NB)2P2]2Si (2a, 2b). The compounds have been characterized by spectroscopic methods and X-ray crystallography. The assembly process has also been followed and one intermediate species [(iPr2NB)2P2][(iPr2NB)P(H)(iPr2NB)P]SiCl (3) has been isolated and fully characterized.
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  • 8
    ISSN: 0009-2940
    Keywords: Methyl trifluoropyruvate ; Tris(trimethylsilyl) phosphite ; Methyl 2-[bis(trimethylsiloxy)phosphoryl]-3,3,3- trifluoro-2-(trimethylsiloxy)propionate ; Bis(trimethylsilyl) [(2,2-difluoro-l-trimethylsiloxy)ethenyl]- phosphonate ; Solid-state structures ; Fluorine ; Phosphorus ; Silicon ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Methyl trifluoropyruvate (1) and tris(trimethylsilyl) phosphite (3) reacted to give methyl 2-[bis(trimethylsiloxy)phosphoryl]- 3,3,3-trifluoro-2-(trimethylsiloxy) propionate (4). Partial hydrolysis furnished propionate 6, the molecular structure of which was obtained in the solid state. Attempted trimethylsilylation of the methylcarboxylato group in 4 using iodotrimethylsilane caused the formation of bis(trimethylsily1) [(2,2- difluoro- 1 -trimethylsiloxy)ethenyl]phosphonate (8). For comparison, methyl pyruvate (2) and 3 gave methyl 2-[bis(trimethylsiloxy)phosphoryl]-2-(trimethylsiloxy)propionate (5).
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  • 9
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 955-958 
    ISSN: 0009-2940
    Keywords: Phosphane sulfides ; Gold(I) complexes ; Sulfide coordination ; Phosphorus ; Sulfur ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Treatment of the ditertiary phosphane sulfides (CH2)n[PPh2S]2, 1a-1d, n = 1-4, with equivalent amounts of (dimethylsulfide)gold(I) chloride (Me2S)AuC1 affords the dinuclear complexes 2a-2d with an AuCl unit attached to each sulfur atom. The chlorides can be converted into the bromides 3a-3c by metathesis using KBr, or by reacting 1d with (tetrahydrothiophene)gold bromide. With [(Ph3P)Au]+ O3SCF3 as the aurating agent for the diphosphane disulfides, the corresponding dicationic products are obtained: {(CH2)n[SPPh2AuPPh3]2}2+ · 2 O3SCF3 (4b-4d, n = 2-4). An excess of the reagents does not lead to polygold clustering at the sulfur atoms, and P-S cleavage occurs instead to give sulfonium salts {S[Au(PPh3)]3}+ X-. The reaction of Ph3PS with equimolar quantities of [ (Ph3P)Au]O3SCF3 leads to the cationic 1:1 complex 5, and with an excess of the agent the P-S bond is ruptured. The structures of compounds 4b and 4d were determined by single-crystal X-ray diffraction. The dications have crystallographic centers ot inversion, the coordination at the gold atoms is linear [4b: 179.03(3)° 4d: 175.29(2)°] and the angles at the sulfur atoms are acute [4b: 97.76(4)° 4d: 96.37(3)°], but there are no short Au-Au contacts.
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  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 1519-1527 
    ISSN: 0009-2940
    Keywords: Phosphorus ; Heterocycles ; Phosphorus ylides ; Phosphoranediyl ; Phosphonio substituents ; P-Cl bond dissociation ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The 1,3-dichloro- and 1,3-dibromo-substituted title compounds 5b, c result from the condensation of triphenylphosphonium-bis(trimethylsily1)methylide 1 with PC13 and PBr3. The chloro derivative 5b undergoes a variety of single and double substitution reactions, of which some have merely been tested and others have been made preparative use of. The substitution of one chloride by an ylidyl, amino, phosphino, or metal carbonyl group is accompanied by the spontaneous dissociation of the other P-CI bond to yield the, 1,3-diphosphetenium chlorides 14/15, 19, 31 and 36, respectively. In other cases (9, 27, 32) dissociation can be achieved by means of a Lewis acid. Protonation of 5b occurs at the carbon ring members; methylation and formation of transition metal complexes occurs at a phosphorus ring member. PCl3 degrades the four-membered ring of5b or enlarges the ring to yield 3,5-diphosphoranediyl-l,2,4-triphospholane derivatives 39, 40, 42.
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