Modification of D-π-A chromophore for the improvement of solubility in water

In order to explore the application of organic D-π-A molecules in bio-imaging, novel D-π-A molecule (chromophore OY) with multi-hydroxyl groups was designed and synthesized. Compared to the traditional D-π-A molecule, chromophore OY showed us great improvement in water solubility. The solubility of chromophore OY in water could reach 200 ppm. Else, the thermal stability of chromophore OY was also studied. Due to the presence of multi-hydroxyl groups, the thermal stability of chromophore OY was not very good. The initial decomposition temperature was just above 100 °C, which was attributed to the dehydration of the hydroxyl groups. Though the SHG effect is not very high, it is large enough for the detection of SHG signal in water solution (0.2-0.3 pm/V).