Tuning the solid-state emission of the analogous GFP chromophore by varying alkyl chains in the imidazolinone ring

New analogues of green fluorescent protein(GFP)chromophore mGFP-Cn(n=1,3,5,11)with alkyl chains of different lengths in the imidazolinone rings were synthesized and their crystal structures were determined.These GFP-like chromophores are all emissive in the solid state.And the solid-state emission quantum yields of increase by extending the lengths of alkyl chains,owing to the fact that the intermolecular pi-pi interactions are significantly weakened based on their crystal structures.