Complex fluoroanions in solution. VII. Replacement of fluoride by trifluoroacetate

Abstract

Binary fluorides of groups III, IV, V, VI, and VII of the periodic table form complex fluoroanions with the trifluoroacetate ion. There is frequently disproportionation to yield species containing more than one trifluoroacetate group. Fluorine and trifluoroacetate exchange reactions are usually slow on the nmr time scale at −70 °C.

Determination by Multi-NMR Studies of New Stable Aluminum Complexes with Pyrophosphate and Fluoride in Aqueous Solution

“…We propose the VI structure (Chart ) to account for its three different multiplicities (Table ). This structure could fit, assuming that the trans 2 J FF coupling constants are small compared to the cis 2 J FF coupling constants (about 83 Hz, see the Results) as is often the case in octahedral complexes. ,, In the c 5 part of the spectrum, the doublet (−138.95 ppm; 2F) is attributed to F c , the triplet (−142.40 ppm; 2F) to F b , and the triplet (−143.40 ppm; 1F) to F a . A spectral simulation with a value of 2 J trans ≈ 15 Hz gives a spectrum very similar to the experimental c 5 subspectrum.…”