Mechanistic Insights Into Nitric Oxide Capture and Release in a Radical‐Scavenging Zinc Ascorbate Metal–Organic Framework

Efficient capture and controlled release of nitric oxide (NO) are essential for therapeutic gas delivery. Here, we investigate NO sorption in bioNICS-1, a zinc-based ascorbate metal-organic framework (MOF), and its propionic acid-modified analogue (bioNICS1-actPA). Structural modulation enhances NO uptake and retention, as evidenced by equilibrium isotherms and pronounced desorption hysteresis that reflect strong host-guest interactions. PXRD and TEM studies reveal adaptive unit-cell distortions upon adsorption, while kinetic and density functional theory (DFT) calculations identify multiple binding sites with distinct interaction strengths. Controlled-release experiments demonstrate humidity-triggered desorption, enabling finely regulated NO delivery. This work uncovers a previously unreported NO binding mechanism in MOFs and establishes radical-scavenging linkers as a powerful design concept for targeted gas capture, positioning bioNICS-1 as a versatile platform for next-generation therapeutic gas delivery technologies.