On the problem of the tetrafluoroborate ion state in complexes with nitrogen-containing organic bases

Using a number of Cu(II), Zn(II), and Cd(II) tetrafluoroborate complexes with nitrogen-containing organic bases as examples, the possible existence of two states of the BF4- ion, namely, the "half-coordination" and counter-ion states, was studied. It was found that in [ML2(BF4)(2)] complexes with strong organic bases (L), the "half-coordination" of the anion exists. As the electron-donating ability of the ligand increases, the interaction between the tetrafluoroborate ion and the metal atom becomes more efficient.