- Synthesis and Structural Aspects of Phosphane - Boranes Derived from Tris(diphenylphosphino)methane, HC(PPh2)3
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The structure of tris(diphenylphosphino)methane, HC(PPh2)3 (1), has been determined by X-ray diffraction.The molecules have approximate C3 symmetry with the lone pairs at the three phosphorus atoms in an "all-trans" orientation.Variable-temperature NMR experiments (+35 to -90 deg C in CH2Cl2) show free intramolecular motion in solution.The partially or fully borylated adducts HC(PPh2)2 (2), HC(PPh2)2 (3), and HC3 (4) have been prepared from 1 and THF x BH3 or Me2S x BH3.For 2 and 3 the internal rotation about the phosphorus-methine carbon bonds is also essentially unhindered, but has been shown to be restricted in 4 (Ea = 31.2 kJ/ mol).The chemical shifts of the methine protons in these compounds can be calculated on the basis of a BH3 substituent constant.Key Words: Triphosphanes / Phosphane-boranes
- Schmidbaur, Hubert,Stuetzer, Albert,Herdtweck, Eberhardt
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p. 1095 - 1100
(2007/10/02)
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- Polydentate Ligands Containing Phosphorus, III Synthesis and Nuclear Magnetic Resonance Studies of Some Unsymmetrical Potentially Tridentate Phosphine Chalcogenide Ligands
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The synthesis via the useful lithium reagent intermediate, (C6H5)2P(S)CH2Li, is reported for eight compounds of the type 2CH, where R is methyl or phenyl and X is an electron pair, oxygen, or sulfur in various combinations.Two related compounds with three and four phosphorus atoms, respectively, per molecule have also been prepared from the same lithium reagent.Tris(diphenylthiophosphoryl)methane has three equivalent phosphorus atoms as indicated by the room temperature phosphorus-31 NMR spectrum, but at reduced temperature a favored conformation exists which has two equivalent phosphorus atoms and a unique one.Other phosphorus-31 and proton NMR data are reported. - Keywords: Polydentate Ligands, Phosphorus Chalcogenides, 31P NMR Spectra
- Grim, Samuel O.,Satek, Larry C.,Mitchell, J. Dale
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p. 832 - 837
(2007/10/02)
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