(15)N-Azides as practical and effective tags for developing long-lived hyperpolarized agents

Azide moieties, unique linear species containing three nitrogen atoms, represent an attractive class of molecular tag for hyperpolarized magnetic resonance imaging (HP-MRI). Here we demonstrate ((15)N)(3)-azide-containing molecules exhibit long-lasting hyperpolarization lifetimes up to 9.8 min at 1 T with remarkably high polarization levels up to 11.6% in water, thus establishing ((15)N)(3)-azide as a powerful spin storage for hyperpolarization. A single ((15)N)-labeled azide has also been examined as an effective alternative tag with long-lived hyperpolarization. A variety of biologically important molecules are studied in this work, including choline, glucose, amino acid, and drug derivatives, demonstrating great potential of (15)N-labeled azides as universal hyperpolarized tags for nuclear magnetic resonance imaging applications.