Figure 3. Spectra evolution of a) [AZOt]0 = 5.5x10 -5 mol.L-1 with increasing CD ; b) [AZOt]0 = 5.3x10-5 mol.L-1 with CD and c) [AZOt]0 = 5.2x10 -5 mol.L-1 with CD and d) for [AZOc]0 = 1.04x10-5 mol.L-1 with CD. Evolution of e) A420 versus [CD] for AZOt ; f) A436 versus [CD] for AZOt ; g) A410 versus [CD] for AZOt ; h) A430 versus [CD] for AZOc. Open circles: experimental points; continuous line: simulation. The variations on UV-visible spectra upon the addition of CD are different for all the tested inclusion complexes. For CD, as already mentioned, the max shifts from 346 to 354 nm. Three isosbestic points are observed at 348, 392 and 460nm. These isosbestic points account for the exchange between two species only, free AZOt and CD complex. For CD, max slightly shifts from 346 to 345 nm and two isosbestic points appear at 284 and 470 nm. As already mentioned, the observation of isosbestic points in these 2.1 stoichiometry indicates that, in the concentration range explored, the amount of 1:1 complex that is transiently formed is undetectable.
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