Bathochromically Shifted Polymethine Dyes Through Silicon Incorporation

Methods to red-shift fluorophores have garnered considerable interest due to the broad utility of low energy light. The incorporation of silicon into xanthene scaffolds has resulted in an array of visible and near-infrared fluorophores. Here, we extend this approach to polymethine dyes, another popular fluorophore class. We found that when oxygen was replaced with SiMe₂, bathochromic shifts of up to 121 nm and fluorophores with emission above 900 nm were achieved.