An efficient, regioselective synthesis of fluorine-substituted arylboronic esters was achieved through fluorine-controlled C-H borylation of arenes with diboron catalyzed by a PSiN-platinum complex. The promising utility of the PSiN-platinum catalyst and its unique regioselectivity were demonstrated for the first time, which would complement the well-developed Ir-catalyzed C-H borylation.

Herein, an unprecedented switching of circularly polarized luminescence (CPL) is described for chiral 4,6-bis(1-(pyren-1-ylamino)propyl)dibenzo[b,d]furan (1). The CPL band of chiral diamine 1, which contains two pyrene rings, can be switched between the monomer and excimer emission regions under concomitant inversion of the handedness, simply by changing the concentration of the fluorophore. In contrast, the maximum photoluminescence (PL) intensity is always observed in the monomer region, regardless of the concentration. The reversal of the intensity ratio of monomer and excimer emission between PL and CPL was attributed to a stronger CPL (|g| = ∼3-4 × 10) contribution from the minor excimer component, which should exhibit an efficient chiral environment around the dimeric pyrenes.

Red- and blue-shifted mechanochromic luminescence (MCL) and single-particle level observation of tricolor MCL of phenanthroimidazolylbenzothiadiazoles are described.

Suguru Ito received his Ph.D. degree from Yokohama National University in 2011 under the supervision of Prof. Masatoshi Asami. After postdoctoral research at Tokyo Institute of Technology under Prof. Nobuharu Iwasawa, he was appointed as an assistant professor at Yokohama National University in 2013. In 2017, he became an associate professor at the same university. His research interest is centered on the creation of functional organic molecules such as organic fluorophores and chiral host compounds.

Herein, the solid-state emission with good fluorescence quantum yields of N-Boc-indolylbenzothiadiazoles as a new class of fluorophores is described. Their solid-state emission covers the wide range of the visible spectrum and the emission color can be tuned easily by changing the substituents on the two heteroaromatic rings. Among these, 3-methylindolyl derivatives exhibit moreover autonomously self-recovering mechanochromic luminescence, whereby the original solid-state emission could be recovered spontaneously at room temperature after exposure to a mechanical stimulus. The emission color, as well as the recovery time for the color change could be tuned via the introduction of different substituents on the benzothiadiazole ring. We propose that the mechanism of the autonomously self-recovering mechanochromic luminescence of 3-methylindolylbenzothiadiazoles is based on a partial amorphization of the crystals upon exposure to the mechanical stimulus, followed by autonomous recovering in the form of recrystallization.