The technology for non-invasive internal analysis without destroying substances or the body is called "nuclear magnetic resonance (NMR) spectroscopy" in the field of chemistry and "magnetic resonance imaging (MRI)" in the medical field. It has become an indispensable tool.However, these are very insensitive compared to other analytical methods.For example, MRI is mainly limited to imaging the 1H nuclei of water molecules that are abundant in the living body, but the polarization rate of each spin is so low that it is insensitive.

　Therefore, the research group focused on MOF, which has been attracting attention as a porous material in recent years, and a technology called the Triplet-DNP method, which can significantly improve the nuclear spin polarization rate at room temperature, leading to high-sensitivity MRI observation of biomolecules. An attempt was made to polarize the nanoporous material.
In order to prolong the time that the polarization is maintained, a newly designed polarization source (pentacene derivative) was introduced into the partially deuterated MOF, and the obtained complex was subjected to Triplet-DNP. Processed.As a result, a clear enhancement was observed in the NMR signal intensity of the complex, and it was confirmed that the ¹H nucleus of the MOF skeleton was highly polarized by about 50 times.

　Since MOF can easily control pore size and surface characteristics by selecting the types of constituent molecules and metal ions, the high polarization of MOF by Triplet-DNP, which was demonstrated for the first time in this study, will be highly sensitive in the future. It is expected to lead to the development of a system that enables MRI observation.

Paper information:[Journal of the American Chemical Society] Dynamic Nuclear Polarization of Metal–Organic Frameworks Using Photoexcited Triplet Electrons