NMR spectral investigation of tantalum pentafluoride reactions with azoles

19F and 1H NMR method has been used to study interaction of tantalum pentafluoride with imidazole, benzimidazole, N-ethyl-, N-methoxymethylbenzimidazole and benztriazole in the nonaqueous solvents. It is shown that [TaF6]- anions and [TaF4L2]+ cationic tetrafluoro-complexes with trans-disposition of nitrogen-containing ligands are formed in the solution. It is concluded that coordination is accomplished by means of the nitrogen atom of pyridine, and bond formation by means of oxygen atom is possible in the case of the N-methoxymethylbenzimidazole. Linear dependence between the values of chemical shifts of 19F NMR in the tetrafluoro-complexes and the values on pKsub(α) azoles is established