Effect of End Groups on Mechanochromism and Electroluminescence in Tetraphenylethylene Substituted Phenanthroimidazoles

Abstract

The design and synthesis of aggregation-induced emission (AIE) luminogens have attracted rapidly growing interest owing to the fundamental significance and diverse applications in mechanosensors, optical recording, security papers, and optoelectronic devices. In this contribution we report design and synthesis of four phenanthroimidazoles 3a–3d and explored their mechanochromic and electroluminescence properties. The phenanthroimidazoles 3a–3d were synthesized by Suzuki coupling reaction of iodophenathroimidazoles 2a–2d having different end groups (H, CH3, CF3, and CN) with 4-(1,2,2-triphenylvinyl)phenylboronic acid pinacol ester in good yields. The single crystal X-ray structures of 2b, 2c, 3a, and 3d are reported and show that the multiple phenyl rings in the TPE unit adopt nonplanar orientation. Their photophysical, aggregation induced emission (AIE), mechanochromic, electrochemical, and electroluminescence properties were studied. The phenanthroimidazoles 3a–3d exhibit strong AIE. High color contrast ...