Synthesis and Photoluminescence Behavior of π-Conjugated 3-Substituted Isoquinoline Derivatives

In this work, a series of π-conjugated isoquinoline derivatives, bearing diverse aryl groups at the 3-position, were synthesized in a facile and straightforward manner. A Pdcatalyzed protocol, the Suzuki-Miyaura coupling of 3-bromoisoquinoline and different aryl boronic acids, was applied, and the structures of the resulting target compounds were determined by 1H-NMR, 13C-NMR, and HRMS. Furthermore, the photophysical properties of these compounds were investigated. Distinct halochromic properties were revealed for them, which exhibited UV emissions in ethanol but visible emissions in an acidic solution.