Influence of alkyl length on properties of piezofluorochromic aggregation induced emission compounds derived from 9,10-bis[(N-alkylphenothiazin-3-yl)vinyl]anthracene

Three 9,10-bis[(N-alkylphenothiazin-3-yl)vinyl]anthracene derivatives with different propyl, hexyl, and dodecyl side chains (AnPh3, AnPh6, and AnPh12) were synthesized and confirmed by standard spectroscopic methods. All of the compounds exhibited obvious aggregation induced emission (AIE) and piezofluorochromic (PFC) properties. The PFC behaviors were investigated and showed that proportional alkyl-length dependent relationship existed not only in the ground states of the compounds, but also in the melted states compared with the fumed states of the compounds. The PFC mechanism was explored and ascribed to the crystalline–amorphous phase transformation. More importantly, these derivatives showed reversible significant PFC properties and reproducibility in various states including fumed, ground, annealed, and melted states, making them promising stimuli-responsive and smart luminescent materials for pressure-sensors, information-recording, and light-emitting device applications.