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  • Articles: DFG German National Licenses  (3)
  • P ligands  (2)
  • Homogeneous catalysis  (1)
  • 1
    ISSN: 0009-2940
    Keywords: Lithiation ; P ligands ; NMR spectroscopy ; Molecular structure ; Hydrogenations ; Hydroformylations ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A facile synthesis of 2′-phosphanyl-1,1′-biphenyl- and 2′-phosphanyl-1,1′ -binaphthyl-2-ols and their silyl ethers has been developed, consisting of electron-transfer-catalyzed ring-opening of dibenzofuran and dinaphthofuran, respectively, subsequent reaction with chlorophosphanes, and work-up with acetic acid or ClSiMe3. Studies of the molecular and crystal structures reveals the presence of P - H - O bridging bonds in the more basic tBuPhP derivative and a nearly perpendicular arrangement of the aryl planes in the biphenyl derivatives. The barrier to rotation of the aryl planes about the C-C axis was determined by NMR in the case of the P-asymmetric derivative 3d, using the appearence of diastereoisomers by atropisomerism and P-asymmetry. Comparative screening tests of the title compounds, phosphanyl phenols and phosphanylnaphthols in homogeneous Rh-catalyzed reactions demonstrate catalytic activity in hydroformylation reactions and superior properties of the biphenyl- and binaphthyl-2-ol derivatives in relation to other P-O ligands.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1434-1948
    Keywords: Phosphorus heterocycles ; P ligands ; Transition metals ; Carbonyl complexes ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The complex chemical behaviour of 2-phosphaindolizines 1 (1,3-azaphospholo[1,5-a]pyridines) towards metal carbonyl compounds was studied. (η1-2-Phosphaindolizine)M(CO)5 complexes 2-4 (M = Cr, Mo, W) were formed from 1 and [(THF)M(CO)5], the cis-L2Cr(CO)4 complex 5f from 1f and tetracarbonyl(norbornadiene) chromium(0). The reaction of 2-phosphaindolizines 1e, 1f, or 1g with tricarbonyl(cycloheptatriene)molybdenum(0) or tricarbonyl(mesitylene)tungsten(0) yielded σ-complexes of the types L2M(CO)4or L3M(CO)3 rather than isolable π-complexes. In one case a strong upfield signal (δ31P = 6.1) was observed with a coordination shift of Δδ = -161.7, which is typical for π-coordination. Prolonged reaction or work-up led, however, to dismutation yielding 1g and the fac-L3Mo(CO)3 complex 6g. X-ray structure analysis of 2a indicates an increased 10π-delocalization compared with 1a and a changed conformation of the acyl substituent. The influence of substituents and metals on the 31P and 13C complexation chemical shifts and coupling constants is discussed.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1434-1948
    Keywords: Methylnickel complexes ; 2-Phosphanylphenolate ; Chelates ; Homogeneous catalysis ; Oligomerization ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reactions of various substituted 2-phosphanylphenols 1a-f with half-molar amounts of cis-[MeNi(μ-OMe)(PMe3)]2 have been found to yield square-planar methyl(2-phosphanylphenolato)(trimethylphosphane)nickel(II) complexes 2a-f. 2JPP coupling constants of 305-316 Hz at low temperature indicate a trans-configuration for the products, while broad 31P-NMR signals at room temperature can be attributed to rapid dissociation of PMe3. Reaction with excess 1 gave rigid bis(2-phosphanylphenolato)nickel(II) complexes as exemplified by 3e, whereas addition of PMe3 to 2a led to the pentacoordinate methyl(2-phosphanylphenolato)bis(trimethylphosphane)nickel(II) complex 4a. Higher yields of 4a and 4d were obtained by reactions of 1a and 1d with Me2Ni(PMe3)3. Single-crystal X-ray diffraction analyses of 3e and 4a have revealed the structures as square-planar trans-bis- and trigonal-bipyramidal mono(2-phosphanylphenolato)nickel(II) P1O-chelate complexes, respectively. The methylnickel complexes 2 and 4 have been found to be effective one-component catalysts for the oligomerization of ethene. High conversions (〉 96%) were achieved with the P-basic derivatives 2e, 2f, and 4d bearing one or two branched alkyl groups (isopropyl, tert-butyl), whereas the diphenylphosphanyl derivatives were less active; 4d gave shorter oligomers than 2e or 2f.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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