(a) FTIR spectra of gels formed by FmocFF, FmocFF/Na+ (1:1), FmocFF/Zn2+ (2:1), and FmocFF/Zn2+ (1:1). (b) Fluorescence emission spectra of FmocFF (DMSO), and gels formed by FmocFF, FmocFF/Na+ (1:1), FmocFF/Zn2+ (2:1), and FmocFF/Zn2+ (1:1) at an excitation wavelength of 260 nm. (c) Molecular clusters of FmocFF. (d-f) Optimized geometries of all the metal ion-containing models of (d) FmocFF/Zn2+ (2:1), (e) FmocFF/Na+ (1:1), and (f) FmocFF/Zn2+ (1:1) obtained by DFT calculations.