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 ΔΕ between the excited singlet state (S ) and triplet state (T ) was lower for TPE-A-Py than for TPE-Py , according to theoretical calculations. Moreover, replacement of I with other anions (PF , N(SO CF ) and BPh ) 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 ) E. coli at low concentration under white-light irradiation very quickly.