Ferrocene-pyrene conjugates for detection of various monovalent anions in solution

The ability of ferrocene-pyrene conjugates towards anion recognition still arouses great deal of interest. However, the reported ferrocene-pyrene compounds allow detection of just one anion. Here, for the first time we present new pyrenyl derivatives of ferrocene, which ensure simultaneous detection of various monovalent anions. The detection of few anions is possible due to the presence of several divergent structural motifs in the structures of the newly synthesized ferrocene-pyrene conjugates. The ferrocene-pyrene conjugates exhibited encouraging properties towards recognition of various monovalent anions. The anion binding properties were probed with nuclear magnetic resonance spectroscopy, fluorescence spectroscopy and voltammetry. The high association constants (2-12·10⁵ M^-1) were found for all the conjugates, together with the low limits of detections (22-64 μM). The applicability of the studied compounds for the analysis of the real water samples was also presented.