Scheme 2. Cyanidin-Based Complexes with Ge (Cy–Ge) Explored with Color Forms of Cyanin.

a1 is obtained from the Cy cation, C; a2, a3, and b1 are from N7, N5, and N4′, respectively; and b2 and b3 are from A74′ and A54′, respectively. The corresponding wavelength of maximum absorbance, λ_max, nm, and oscillator strength, f, are shown for each complex.