Long-Alkyl Chain Functionalized Imidazo[1,5-a]pyridine Derivatives as Blue Emissive Dyes

A series of boron difluoride compounds with 2-(imidazo[1,5-a]pyridin-3-yl)phenols bearing alkylic chains at the 1-position has been synthesized and characterized both with 1H and 13C NMR and infrared spectroscopy. This series of compounds displayed blue emission in solution and in thin polymeric films, with interesting features like large Stokes shifts and good fluorescence quantum yields. Time-Dependent Density Functional Theory (TD-DFT) calculations allowed for the identification of the main electronic transitions as intra ligand transitions (as corroborated by the Natural Transition Orbitals (NTOs) shapes.