Synthesis of novel polyurethanes with fluorescein linkages

The reaction of n-propylisocyanate with fluorescein (FLU) has been performed in N,N'-dimethylacetamide (DMAc) in the presence of triethylamine and the resulting bis-adduct has been obtained in high yield and finally was used as a model compound for the polymerization reactions. The step-growth polymerization reaction of the monomer FLU with hexamethylene diisocyanate (HMDI), isophorone diisocyanate (IPDI), and toluene-2,4-diisocyanate (TDI) was carried out in DMAc solution and in the presence of pyridine as a catalyst. The above polymerization reactions lead to the formation of novel aromatic-aliphatic polyurethanes having fluorescein moieties in the main chain. The resulting novel polyurethanes have an inherent viscosity in a range of 0.08-0.23 dLg(-1) and show light-violet fluorescence property and could be used as photoactive polymers for labeling materials. These polyurethanes were characterized by IR, (1)H NMR, TGA/DTG, DSC and elemental analyses. Some physical properties of this novel polymers are reported.