- Bis(triphenyl-λ5-phosphanylidene)ammonium fluoride: A reactive fluoride source to access the hypervalent silicates [Me nSiF5-n]- (n = 0-3)
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A new synthesis of bis(triphenyl-λ5-phosphanylidene) ammonium fluoride ((Ph3PNPPh3)F, abbreviated as (PNP)F), is described. The title compound has been fully characterized by multinuclear NMR spectroscopy, vibrational spectroscopy, elemental analysis and single crystal and powder X-ray diffraction for the first time. In the solid state (PNP)F exists as a covalent molecular compound, in which the fluoride ion is asymmetrically bonded to the two phosphorus atoms of the [PNP]+ cation. The phosphorus-fluorine bond with 181.98(13) pm is surprisingly long and the longest P-F bond in any phosphorane. (PNP)F can be assumed to be a very good source of reactive fluoride. To investigate the fluoride ion donating properties, (PNP)F was reacted with a range of different fluoromethylsilanes MenSiF4-n (n = 0-4). Reactions of (PNP)F with the fluoromethylsilanes were performed in aceto- or propionitrile and in 1,2-dimethoxyethane under inert conditions. The resulting hypervalent fluoromethylsilicates [MenSiF5-n]- (n = 0-3) were fully characterized by multinuclear NMR and vibrational spectroscopy and single crystal X-ray diffraction. From the reaction of (PNP)F with Me 4Si in acetonitrile, the starting materials were recovered unchanged. To aid the understanding of the experimental results the fluoride ion affinities (FIA) for these silanes have been calculated by DFT calculations on the PBE0/def2-TZVPP level of theory. The fluoride ion affinity in the series of MenSiF4-n (n = 0-4) decreases with the number of methyl groups and is too low for Me4Si to bind a fluoride ion under these reaction conditions.
- Bolli, Christoph,Gellhaar, Jorit,Jenne, Carsten,Kessler, Mathias,Scherer, Harald,Seeger, Helene,Uzun, Rabiya
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supporting information
p. 4326 - 4334
(2014/03/21)
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- Zwitterionic stabilization of a reactive cobalt tris-isocyanide monoanion by cation coordination
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A break with tradition: The cation, [Ph3P=N=PPh 3]+ ([PPN]+), was found to provide a stabilizing η2-arene interaction to the coordinatively unsaturated, tris-isocyanide monoanion, [Co(CNArMes2) 3]-(ArMes2=2,6-(2,4,6-Me3C 6H2)C6H3); Co=purple, N=light purple, and P=orange). The resulting zwitterion is a source of [Co(CNAr Mes2)3]- anions, performing nucleophilic additions, carbon-element bond activations, and multistep decarbonylations.
- Carpenter, Alex E.,Margulieux, Grant W.,Millard, Matthew D.,Moore, Curtis E.,Weidemann, Nils,Rheingold, Arnold L.,Figueroa, Joshua S.
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supporting information
p. 9412 - 9416
(2012/11/07)
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- A new and convenient method for the synthesis of strong non-ionic bases
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Various strong non-ionic phosphazene bases were obtained by a new, efficient and very simple method involving the lithium phosphonium azayldiide Ph3P=NLi (2) as a precursor. The Royal Society of Chemistry 2006.
- Taillefer, Marc,Rahier, Nicolas,Hameau, Aurelien,Volle, Jean-Noel
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p. 3238 - 3239
(2008/09/20)
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