Self-Assembled Pt Metallosupramolecular Tubular Cage as Dual Warhead Antibacterial Agent in Water.

Development of photosensitizer-based self-assembled metallosupramolecular architectures with important applications is an emerging trend in supramolecular chemistry. In this study, we report a new benzothiadiazole-based tetra-pyridyl ligand (), which upon self-assembly with a block 90° Pt(II) acceptor generated an unprecedented tetrafacial Pt(II) photoactive tubular molecular cage (). This cage could bring an extraordinary photosensitizer, benzothiadiazole, into water which is otherwise insoluble. is fluorescent and shows photogeneration of singlet oxygen in an aqueous medium. These features make a potent antimicrobial agent in water in both the presence and absence of light. In comparison to its building blocks and water-soluble alkylated charged ligand (), the cage shows much enhanced photoinduced antibacterial activity against methicillin-resistant (MRSA) as a representative of Gram-positive bacteria and (PA) as a representative of Gram-negative bacteria. is successful at inactivating the bacterial growth via both photoactivation of molecular oxygen and membrane depolarization mechanisms, thus proving to be a dual warhead. Inactivation of bacteria in water using such a supramolecular architecture is noteworthy and can shed light on the generation of new antimicrobial supramolecular systems.