Fluorescent coumarin derivatives with large stokes shift, dual emission and solid state luminescent properties: An experimental and theoretical study

New red-fluorescent calcium indicators for optogenetics, photoactivation and multi-color imaging.

Fluorescent boron(III) iminocoumarins (Boricos)

A series of cyanostilbene based D−π–A derivatives, comprising 6-(diethylamino)coumarin as a donor and benzene and benzothiazole as acceptors bridged by different π-spacers (benzene, thiophene), have been synthesized and characterized. The influence of π-spacer and acceptor units on the photophysical, electrochemical, and thermal properties of the dyes was investigated in detail. The incorporation of coumarin donor results in a significant increase of the fluorescence quantum yield. In the solution phase, the absorption and emission of the dye TB show a bathochromic shift (TB > BBT) indicating dominant dynamic intramolecular rotations (IMR) behavior of cyano group over the acceptor functionality. On the other hand, the emission is reversed (BBT > TB) in the case of aggregates. The synergistic combination of intramolecular planarization and torsional alleviation around cyanostilbenes induced by strong electron withdrawing benzothiazole unit in BBT enabled pronounced bathochromic shift upon aggregation. Upon...

Huai Zu Peng

Papers

The synthesis and optical characterization of novel iminocoumarin derivatives