Ferromagnetic supramolecular metal-organic frameworks for active capture and magnetic sensing of emerging drug pollutants

Capture and sensing of emerging pollutants is one of the increasing environmental concerns due to the adverse ecological and human health effects. Here, we report the synthesis of a supramolecular metal-organic framework (SMOF) [CrCu₆(μ-H₂O)₆(μ₃-OH)₆(μ-adeninato-κN3₃:κN9)₆](SO₄)_1.5 which is able to capture anionic drugs and exhibits magnetic properties useful for sensing purposes. The features of the nucleobase decorated CrCu₆ building block allow the incorporation of up to 9 drug molecules (i.e., ibuprofen and naproxen in this work) per heptameric entity. In addition, we provide a simple way to quantify the incorporated number of drug molecules through a magnetic sustentation experiment in which the field required to keep the particles attached to the electromagnet pole is linearly related to the total mass of the anionic counterion. In this way, it also provides an easy way to determine the amount of entrapped drug molecules, making this SMOF a promising candidate for environmental remediation technologies.