Imidazole-Based Metal-Organic Materials: Chemistry Design via Metal Cations for Advanced Chemical Sensors

Metal-organic frameworks are indispensable to enabling new technologies such as gas separation and chemical sensing application. However, achieving ultrasensitive and highly reliable MOF-based sensing materials faces fundamental challenges of high resistance and gas-sensitive inertness. Herein, a series of metal-organic materials (MOMs) constructed from 2-methylimidazole and different metal cations (M = Ag, Cu, Ni, Mn, Mo, etc.) were designed and synthesized for advanced chemical sensing applications. Their sensing properties and underlying mechanism are investigated by gas exposure/removal tests and density functional theory theoretical calculation. The results show that the MOM with two-dimensional topologies and low formation energy plays a crucial role in kinetically dominated gas sensing processes. As a result, the optimal sample AgMeIm exhibits excellent sensing sensitivity and stability during ethanol gas detection at room temperature. Our results highlight the coordination properties of different metal nodes with methylimidazole, with direct application to understanding and developing more sensitive and reliable chemical sensors based on chemical or biological activity relevant to MOMs. Moreover, considering the flexible diversity of metal and ligand designs, diversified MOMs with superior sensing properties can be generally fabricated, even in systems that go far beyond traditional coordination chemistry.