N-BODIPYs Come into Play: Smart Dyes for Photonic Materials

Abstract

N-BODIPYs (diaminoboron dipyrromethenes) are unveiled as a new family of BODIPY dyes with huge technological potential. Their synthetic access is accomplished from a judicious design focused on stabilizing the involved diaminoboron chelate. Once stabilized, achieved N-BODIPYs retain the effective photophysical behavior exhibited by other boron-substituted BODIPYs, such as the O-BODIPYs. However, key bonding features of nitrogen, when compared with oxygen (enhanced bond valence and different bond directionality) open up new possibilities for functionalizing BODIPYs, allowing the increase of the number of pendant moieties (from two in O-BODIPYs, up to four in N-BODIPYs) near the chromophore and, therefore, a smarter photophysics modulation. As a proof of concept, we describe: (1) the low-cost and straightforward synthesis of a selected battery of N-BODIPYs; (2) their outstanding photophysical properties, when compared with related effective dyes (excellent emission signatures, including fluorescence in solid state, or noticeable lasing capacities in liquid phase and doped into polymers, improving the laser performance of parent F-BODIPYs); (3) the versatility of the diaminoboron moiety to multifunctionalize BODIPYs, allowing the preparation of both symmetric and asymmetric dyes; (4) the capability of such a versatility to finely modulate the dye photophysics directed to different photonic applications, from lasing to chemosensing.