Hexaphenylcarbodiphosphorane is the organophosphorus compound with the formula C(PPh3)2 (where Ph = C6H5). It is a yellow, moisture-sensitive solid. The compound is classified as an ylide and as such carries significant negative charge on carbon. It is isoelectronic with bis(triphenylphosphine)iminium. The P-C-P angle is 131°.[1] The compound has attracted attention as an unusual ligand in organometallic chemistry.[2]

The pure compound has two crystalline phases: a metastable monoclinic C2 phase that is triboluminescent, and an orthorhombic P222 form that is not. Both polymorphs are photoluminescent, with respective peak wavelengths at 540 and 575 nm.[3]

Preparation

The compound was originally prepared by deprotonation of the phosphonium salt [HC(PPh3)2]Br using potassium.[4]

An improved procedure entails production of the same double phosphonium salt from methylene bromide. The double deprotonation is effected with potassium amide.[5]

References

  1. ^ Tonner, Ralf; Oexler, Florian; Neumueller, Bernhard; Petz, Wolfgang; Frenking, Gernot (2006). "Carbodiphosphoranes: The Chemistry of Divalent Carbon(0)". Angewandte Chemie International Edition. 45 (47): 8038–8042. doi:10.1002/anie.200602552. PMID 17075933.
  2. ^ Petz, W.; Frenking, G. (2010). "Carbodiphosphoranes and Related Ligands". Transition Metal Complexes of Neutral eta1-Carbon Ligands. Topics in Organometallic Chemistry. Vol. 30. Top. Organomet. Chem. pp. 49–92. Bibcode:2010tmcn.book...49P. doi:10.1007/978-3-642-04722-0_3. ISBN 978-3-642-04721-3.
  3. ^ Hardy, Gordon E.; Kaska, William C.; Chandra, B. P.; Zink, Jeffrey I. (March 1981). "Triboluminescence-structure relationships in polymorphs of hexaphenylcarbodiphosphorane and anthranilic acid, molecular crystals, and salts". Journal of the American Chemical Society. 103 (5): 1074–1079. doi:10.1021/ja00395a014.
  4. ^ Ramirez, Fausto; Desai, N. B.; Hansen, B.; McKelvie, N. (1961). "Hexaphenylcarbodiphosphorane, (C6H5)3P:C:P(C6H5)3". Journal of the American Chemical Society. 83 (16): 3539–40. doi:10.1021/ja01477a052.
  5. ^ Gruber, Marco; Bauer, Walter; Maid, Harald; Schöll, Kilian; Tykwinski, Rik R. (2017). "Synthetic and NMR Studies on Hexaphenylcarbodiphosphorane (Ph3P=C=PPh3)". Inorganica Chimica Acta. 468: 152–158. doi:10.1016/j.ica.2017.04.018.
Allikas: http://en.wikipedia.org/wiki/Hexaphenylcarbodiphosphorane
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