Molecular Multi‐Wavelength Optical Anion Sensors

Polychromatic fingerprinting of simple anions (halides, oxo anions) is achieved by employing neutral and charged multicolor fluorescent probes based on ferrocene‐spaced dansyl and naphthyl groups (1/1+; 2/2+). The conformation of the neutral double dye sensor 2 has been elucidated by NMR spectroscopic techniques (in solution), by X‐ray crystallography (solid state) and by DFT calculations (gas phase). The double‐dye receptors 2/2+ exhibit specific emission responses in the presence of anions X– when excited at the absorption maxima of the dyes (fingerprint).