Pentafluoroethylaluminates: A Combined Synthetic, Spectroscopic, and Structural Study.

Salts of the unprecedented tetrakis(pentafluoroethyl)-alu-min-ate anion [Al(C2F5)4]- were obtained from AlCl3 and LiC2F5. They were isolated with different countercations and characterized by NMR and vibrational spectroscopy and mass spectrometry. Degradation of the [Al(C2F5)4]- ion was found to proceed via 1,2-fluorine shifts and stepwise loss of CF(CF3) under formation of [(C2F5)4- n AlF n ]- (n = 1-4) as assessed by NMR spectroscopy and mass spectrometry and supported by results of DFT calculations. In addition, the [(C2F5)AlF3]- ion was structurally characterized.