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

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 Δ Ε ST between the excited singlet state ( S 1 ) and triplet state ( T 1 ) was lower for TPE‐A‐Py + than for TPE‐Py + , according to theoretical calculations. Moreover, replacement of I − with other anions (PF 6 − , N(SO 2 CF 3 ) 2 − and BPh 4 − ) 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.