The Zinc‐Dependent Fluorescence of a Synthetic GFP‐Like Chromophore in Organic Solvents

A synthetic green fluorescent protein analogue showed Zn2+‐induced fluorescence in organic solvents (Φ = 0.07 at r.t. and up to 0.3 at low temperature). The experimental observations and theoretical calculations suggest that Zn2+ binding inhibits the free rotation of an aryl–alkene bond, which allows excited molecules to relax through the emission pathway instead of the thermodynamic pathway. The solvent influenced the fluorescence intensities and wavelengths by direct or indirect interactions with the molecules.