Disproportionation of AlF3 center dot 9H(2)O in donor solvents

AlF3. 9H(2)O was found to disproportionate in dimethylformamide, dimethyl s ulfoxide, tetramethylurea, and hexamethylphosphoramide solutions to produce six-coordinate fluoro solvate species AlF(n)Sol(6-n) (Sol is water or dono r solvent) and the tetrafluoroaluminate anion. The mononuclear tetrahedral configuration of AlF4- was supported by F-19 and Al-27 NMR spectra. For AlF 4- anion in donor solvents, chemical shifts and F-19-Al-27 spin coupling co nstants were determined. Disproportionation depends on the donor solvent : water molar ratio (R): at R > 20, AlF4- incorporates 58-80% of aluminum in solution. At 265-310 K, the intermolecular ligand exchange between six- and four-coordinate aluminum fluoro species is not observed.