Simple anthracene derivatives: different mechanoluminescence properties tailored only by a thiophene group

Abstract

Here, anthracene was selected as the fluorescent core, then boronic ester and the self-assembling thiophene group were introduced to the “9” and “10” sites of anthracene, respectively. By changing the linked sites of thiophene and introducing a methyl unit to thiophene, four molecules, B2T, B3T, B2TM and B3TM, were synthesized with different mechanoluminescence (ML) properties. When the powders or crystals of B3T or B3TM were scraped, bright blue emission was observed even under daylight. In particular, under continuous mechanical stimulation, these bright ML phenomena can be maintained for a long time. The careful analyses demonstrated that the different linked sites of the thiophene unit to anthracene and the introduction of the methyl group to thiophene influenced the intermolecular interactions and molecular packing modes, and then caused these four compounds to exhibit different ML properties.