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 ΔΕST 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 (ampr ) E. coli at low concentration under white-light irradiation very quickly.