Tunable Visible and Near‐IR Photoactivation of Light‐Responsive Compounds by Using Fluorophores as Light‐Capturing Antennas

Although the corrin ring of vitamin B₁₂ is unable to efficiently absorb light beyond 550 nm, it is shown that commercially available fluorophores can be used as antennas to capture long‐wavelength light to promote scission of the Co? C bond at wavelengths up to 800 nm. The ability to control the molecular properties of bioactive species with long visible and near‐IR light has implications for drug delivery, nanotechnology, and the spatiotemporal control of cellular behavior.