Dimerizing Heptamethine Cyanine Fluorophores from the Meso Position: Synthesis, Optical Properties, and Metal Sensing Studies.

A series of eight dimeric heptamethine cyanine fluorophores were synthesized, purified, and produced in moderate yields by connecting two heptamethine dyes from their meso position. Their physicochemical properties were predicted, and their optical properties and photothermal stability were studied. They showed selective absorbance and fluorescence quenching in the presence of copper(II) ions. This study serves as a basis for exploring the effects of dimerization of heptamethine cyanine fluorophores and their potential use for various biomedical applications.