Functional Ionic Porous Frameworks Based on Triaminoguanidinium for CO2 Conversion and Combating Microbes

Porous organic frameworks (POFs) with heteroatom rich ionic backbone have emerged as advanced materials for catalysis, charge-specific molecular separation and antibacterial activity. The loading of metal ions further enhances Lewis acidity augmenting the activity associated with the frameworks. Metal-loaded ionic POFs however often suffer from physicochemical instability, limiting their scope for diverse applications. Herein, we report the fabrication of triaminoguanidinium-based ionic POFs through Schiff base condensation in a cost-effective and scalable manner. The resultant N-rich ionic frameworks facilitate selective CO2 uptake and provide high metal (ZnO, 57.3 ± 1.2%) loading capacity. The hierarchically mesoporous ZnO-rich metalated frameworks (Zn/POFs) show remarkable catalytic activity in the cycloaddition of CO2 and epoxides into cyclic organic carbonates under solvent-free condition with high catalyst recyclability. In addition, both ionic POFs and Zn/POFs exhibit robust antibacterial (Gram-positive, S. aureus and Gram-negative, E. coli) and antiviral activity targeting HIV and VSV-G enveloped lentiviral particles. The enhanced catalytic, as well as broad-spectrum antimicrobial activity, are likely due to the synergistic effect of triaminoguanidinium ions and ZnO infused with the frameworks. We thus establish triaminoguanidinium-based POFs and Zn/POFs as a new class of multifunctional materials for environmental remediation and biomedical applications.