Dicyanoboron diketonate dyes: Synthesis, photophysical properties and bioimaging

A new class of dicyanoboron diketonates (B(CN)(2)) was synthesized and the photophysical properties were investigated. The B(CN)(2) complexes exhibited high molar absorption coefficients, large Stokes shifts, high photostability and low cytotoxicity. Especially, the emission of the B(CN)(2) extended into the deep red region. The extensive it conjugation and the presence of intramolecular charge transfer (ICT) transitions are responsible for their red-shifted emission. Their fluorescence are very sensitive to the polarity of the solvents. They are highly emissive in low polarity solvents, but weakly fluorescent in polar solvents. Cell imaging experiments demonstrated its potential application as a probe in bioorganisms due to its excellent imaging contrast. This strategy represents a facile approach to modulate the photophysical properties of dyes. (C) 2014 Elsevier Ltd. All rights reserved.