Tetrasubstituted olefinic xanthene dyes: synthesis via Pd-catalyzed 6-exo-dig cyclization/C-H activation of 2-bromobenzyl-N-propargylamines and solid state fluorescence properties.

Tetrasubstituted olefin based new xanthene derivatives have been synthesized via palladium-catalyzed carbopalladation/C-H activation of 2-bromobenzyl-N-propargylamine derivatives. The synthesized compounds display a pronounced solid state fluorescence due to their restricted internal rotation of a C-Ar bond in the solid or aggregation state.