Photophysical and Electrochemiluminescence of Coumarin-Based Oxazaborines

We describe the synthesis, electrochemistry, photophysics, computational analysis and electrochemiluminescence (ECL) of a new series of oxazaborine molecules. Our strategy is based on the modification of the coumarin-oxazaborine moiety to be directly joined through a carbon-carbon bond, forming donor-acceptor (D-A) chromophores. These new structures substantially change the electron distribution as well as photophysical and electrochemical behaviors with a strong effect on the final quantum yield. For all compounds, we observed a very high PL quantum yield (70–75 %) and relatively accessible first oxidation and first reduction. All of these characteristics allow us to study the ECL of these molecules, obtaining a very high ECL efficiency that is four times higher than the standard dyes, opening the application of oxazaborine as bright ECL luminophores.