0000000000461720
AUTHOR
Jiří Mareš
Hyper-CEST NMR of metal organic polyhedral cages reveals hidden diastereomers with diverse guest exchange kinetics.
AbstractGuest capture and release are important properties of self-assembling nanostructures. Over time, a significant fraction of guests might engage in short-lived states with different symmetry and stereoselectivity and transit frequently between multiple environments, thereby escaping common spectroscopy techniques. Here, we investigate the cavity of an iron-based metal organic polyhedron (Fe-MOP) using spin-hyperpolarized 129Xe Chemical Exchange Saturation Transfer (hyper-CEST) NMR. We report strong signals unknown from previous studies that persist under different perturbations. On-the-fly delivery of hyperpolarized gas yields CEST signatures that reflect different Xe exchange kinetic…
Encapsulation of xenon by bridged resorcinarene cages with high 129Xe NMR chemical shift and efficient exchange dynamics
Functionalized cages encapsulating xenon atoms enable highly sensitive, background-free molecular imaging through a technique known as HyperCEST 129Xe MRI. Here, we introduce a class of potential biosensor cage structures based on two resorcinarene macrocycles bridged either by aliphatic carbon chains or piperazines. First-principles-based modeling predicts a high chemical shift (about 345 ppm) outside the typical experimental observation window for 129Xe encapsulated by the aliphatically bridged cage and two 129Xe resonances for the piperazine-bridged cages corresponding to single and double loading. Based on the computational predictions as well as 129Xe chemical exchange saturation trans…