Pyridinium‐Substituted TetraphenylethyleneEntailing Alkyne Moiety: Enhancement of Photosensitizing Efficiency and Antimicrobial Activity

Abstract

Apart from sensing and imaging, luminogens with aggregation-induced emission (AIE) are also interesting for photosensitizing. The photosensitizing behavior and bacteria-killing performance of a pyridinium-substituted tetraphenylethylene with an alkyne group (TPE-A-Py⁺ ) is reported herein. Interestingly, TPE-A-Py⁺ exhibits higher photosensitizing efficiency than TPE-Py⁺ (without alkyne group) when I^- was used as a counteranion. This is well explained by the fact that the ΔΕ_ST between the excited singlet state (S₁ ) and triplet state (T₁ ) was lower for TPE-A-Py⁺ than for TPE-Py⁺ , according to theoretical calculations. Moreover, replacement of I^- with other anions (PF₆^- , N(SO₂ CF₃ )₂^- and BPh₄^- ) led to a decrease of photosensitizing efficiency for TPE-A-Py⁺ . Notably, TPE-A-Py⁺ could be used as an efficient photosensitizer to photo-inactivate ampicillin-resistant (amp^r ) E. coli at low concentration under white-light irradiation very quickly.