A highly emissive cruciform triarylborane as a ratiometric and solid state fluorescence sensor for fluoride ions

We disclosed a novel cruciform tri-coordinate organoboron compound, 2',5'-bis{[(4-dimesitylboryl)phenyl]ethynyl}-1',4'-bis[(4-N,N-diphenylamino)phenyl]-[1,1':4',1']terphenyls, which displays a characteristic intramolecular charge transfer transition and is highly emissive both in solutions and solid state. The complexation with fluoride ions induces a large blue shift in fluorescence, enabling ratiometric fluorescence sensing of fluoride. In addition, its prompt response to fluoride ions was also observed even in the solid state. (C) 2011 Elsevier Ltd. All rights reserved.