Highly fluorescence emissive 5, 5′-distyryl-3, 3′-bithiophenes: Synthesis, crystal structure, optoelectronic and thermal properties

Seven 5,5'-distyryl-3,3'-bithiophene derivatives (1-7) with A-pi-A or D-pi-D structures were synthesized and their photophysical, electrochemical, and thermal properties were investigated. Photoluminescence experiments showed that the compounds gave a high fluorescence emission. In photophysical studies, compound 2, which has a nitro substituent, showed significant solvatochromism, thermochmmism and aggregation induced emission (AIE) characteristics. Cyclic voltammetry and thermogravimetric analysis indicated that 2 had good electron affinity and thermal stability. The molecular structures and packing arrangements were identified by single crystal X-ray diffraction. Theoretical calculations for the electronic transitions explained the observed special optical behaviors of 2 well. The excellent optical properties of 2 made it a promising emitter for optoelectronics.