Synthesis of unsymmetrical Si-rhodamine fluorophores and application to a far-red to near-infrared fluorescence probe for hypoxia.

Si-Rhodamines are bright fluorophores with red to near-infrared (NIR) emission, and are widely used for fluorescence imaging of biological phenomena. Here, in order to extend the scope of Si-rhodamine fluorophores, we established a versatile synthesis of unsymmetrical Si-rhodamines. To illustrate its value, we used one of these new fluorophores to synthesize a far-red to NIR fluorescence probe for hypoxia, and showed that it can visualize hepatic ischemia in mice in vivo.