Push-pull amino-succinimidyl ester thiophene-based as fluorescent dyes: synthesis and optical characterization

The design and synthesis of new fluorescent dyes with emission range at 490–650 nm are described. Their structural and electronic properties have been characterized by both experimental techniques and quantumchemical calculations. The chromophores are donor–p-bridge–acceptor push–pull compounds with a p bridge of phenyl and thiophene rings and their combination. Compared with previous thiophene fluorophores, these dyes show significant redshift in the absorption and emission spectra and offer compact, red-emitting fluorophores. The dyes have amino succinimidyl active ester and can be readily conjugated to proteins, polymers and other amino-group-containing materials.