Ca MAS-DNP NMR of Frozen Solutions for the Investigation of Calcium Ion Complexation.

Calcium ion complexation in aqueous solutions is of paramount importance in biology as it is related to cell signaling, muscle contraction, or biomineralization. However, Ca-complexes are dynamic soluble entities challenging to describe at the molecular level. Nuclear magnetic resonance appears as a method of choice to probe Ca-complexes.

Monitoring Crystallization Processes in Confined Porous Materials by Dynamic Nuclear Polarization Solid-State Nuclear Magnetic Resonance.

Establishing mechanistic understanding of crystallization processes at the molecular level is challenging, as it requires both the detection of transient solid phases and monitoring the evolution of both liquid and solid phases as a function of time. Here, we demonstrate the application of dynamic nuclear polarization (DNP) enhanced NMR spectroscopy to study crystallization under nanoscopic confinement, revealing a viable approach to interrogate different stages of crystallization processes. We focus on crystallization of glycine within the nanometric pores (7-8 nm) of a tailored mesoporous SBA-15 silica material with wall-embedded TEMPO radicals.