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The Bis(pentafluoroethyl)phosphinous Acid (C 2 F 5 ) 2 POH

2009; Wiley; Volume: 15; Issue: 14 Linguagem: Inglês

10.1002/chem.200801837

1521-3765

Berthold Hoge, Julia Bader, Helmut Beckers, Yong Seol Kim, R. Eujen, Helge Willner, Nikolai Ignatíev,

Organometallic Complex Synthesis and Catalysis

The industrial product (C(2)F(5))(3)PF(2) is transformed into the phosphinic acid chloride (C(2)F(5))(2)P(O)Cl, which reacts with an excess of Bu(3)SnH in a clean, multistep reaction to give the stannyl derivative (C(2)F(5))(2)POSnBu(3). Subsequent treatment with gaseous HBr leads to the formation of (C(2)F(5))(2)POH, which is isolated in 70 % yield. Besides (CF(3))(2)POH, bis(pentafluoroethyl)phosphinous acid, (C(2)F(5))(2)POH, represents the second known example of a phosphinous acid that is predicted by using density functional theory calculations at the B3PW91/6-311G(3d,p) level to be more stable than the phosphane oxide tautomer, the energy difference being 11.7 kJ mol(-1). Only the phosphinous acid isomer is detectable in the gas phase and in solution. However, investigations of the neat liquid reveal a temperature-dependent tautomeric equilibrium with the phosphane oxide isomer (C(2)F(5))(2)P(O)H, which is characterized by vibrational and multinuclear NMR spectroscopic methods in combination with quantum-chemical calculations.