Figure 5. NMR 31P {H} spectra of free cyclen II (a), spectra obtained by adding 0.1 mol (b), 0.2 mol (c), 0.5 mol (d) and 1.0 mol (e) Ga (NO₃) ₃ to the initial solution, at T = 298 K.Substituted cyclen II (a) and assumed structure models of Ga^{3 +}compound complex (b)