2,2'‐Diamino‐6,6'‐diboryl‐1,1'‐binaphthyl: a Versatile Building Block for Temperature‐dependent Dual Fluorescence and Switchable Circularly Polarized Lumincescence

The temperature‐dependent dual fluorescence and switchable circularly polarized luminescence (CPL) are two highly pursued but challenging properties for small organic molecules (SOMs). We herein disclose a triarylborane π‐system based on a 2,2'‐diamino‐6,6'‐diboryl‐1,1'‐binaphthyl scaffold, which can serve as a versatile building block to achieve these two properties by simply choosing different amino groups. The BNMe2‐BNaph with less bulky dimethylamino groups displays temperature‐dependent dual fluorescence, enabling the great utility as the highly sensitive ratiometric fluorescence thermometer. On the other hand, the BNPh2‐BNaph with bulky diphenylamino groups exhibits intense fluorescence in both solution and solid state. The change of solvent from the nonpolar cyclohexane to the highly polar MeCN not only shifts the CPL position to much longer wavelength but also invert the CPL sign. In addition, the complexation of BNPh2‐BNaph with fluoride is able to greatly enhance the CPL intensity with glums of the fluoride complexes up to the order of 10–2.

from A via a.sfakia on Inoreader http://bit.ly/2Td32BA