The effect of fluorinated substituents on some solution properties of metal acetylacetonates

Academic Article

Abstract

  • The effect of the CF group upon substitution for a CH group is noted in three different solution studies of acetylacetone (AA), trifluoroacetylacetone (TFA), and hexafluoroacetylacetone (HFA) and their corresponding metal complexes. The lability of dimethyl sulfoxide (DMSO) in exchanging from the axial positions of Ni(AA) complexes is dramatically altered by substitution of CF groups with k‡(AA)>k‡(TFA)>k‡(HFA). The diminution in rate of exchange can be explained by the electron withdrawal of the CF group. A good fit of the rate constants to the Hammett equation is noted. The substitution of a CF group for a CH group causes the bromination of Al(TFA) by N-bromosuccinimide to be about 2800 times slower than Al(AA) (k = 6.7 ± 0.5 sec at 25°C). The C and H NMR chemical shifts of AA, TFA and HFA were measured and compared with electron densities for the three compounds calculated by the INDO formalism. The H and methine C shifts show a linear correlation with electron density. The other C chemical shifts can best be explained by assuming that AA is quasi-aromatic and the paramagnetic effect is dominant. © 1978. 3 3 2 3 3 3 3 3 3 -1 13 1 1 13 13
  • Authors

    Digital Object Identifier (doi)

    Author List

  • Watkins CL; Harris ME
  • Start Page

  • 1769
  • End Page

  • 1775
  • Volume

  • 40
  • Issue

  • 10