Tridurylboranes extended by three arylethynyl groups as a new family of boron-based π-electron systems

[GRAPHICS] A series of tris(phenylethynylduryl)boranes (R-C6H4-C=C-duryl)(3)B with various substituents R have been prepared as air-stable solids owing to the steric protection of the boron atom by the three bulky duryl groups. These compounds show unique photophysical properties due to the p(pi)-pi* conjugation through the p-orbital on the boron atom. In particular, a push-pull type derivative with R = NMe2 exhibits a significant solvatochromism of fluorescence from blue to orange colors.