Intertwined detection and recognition roles of tetrazine in synergistic anion-π and H-bond based anion receptor.

: The intrinsic properties of tetrazine as a p-anion receptor and as an on/off recognition probe merged with H-bond ability of an urea motif into a single architecture designs a new generation of well-defined anion receptors. Complexation properties directly benefit from the dual and synergistic contribution of tetrazine and urea. In this study, we report on the synthesis and assessment of binding properties to anions of diverse geometries. Association constants have been predicted by theoretical calculations and evaluated by multiple and complementary experimental techniques including electrospray-mass tandem spectroscopy, NMR, UV-Visible, steady state fluorescence spectroscopies and time resolved fluorescence. These results provide the basis for a better understanding of both the complexation and the anion-dependent quenching mechanism.