Synthesis and characterisation of new phosphonate labelled cyanines

We present the synthesis of new N-1,5 phosphosubstituted pentamethine cyanine dyes in high yields. The compounds are obtained from original N-phosphonates quaternary heterocyclic ammonium salts, with an activated methyl group in the 2-position. Moreover, the aqueous solubility of these new dyes is emphasized. The spectroscopic parameters of the new compounds are described together with a preliminary study of divalent cations complexation in fluorescence.