Multifunctional Spirocyclic Systems

Figure 5

Absorption spectra of the compound 5a in acetonitrile (𝐶=4,82×10⁻⁵M,𝑇=30^∘C) before (1), immediately after (2) and 20 seconds after (3) addition of zinc salt ([Zn⁺⁺]=1,12×10⁻³).