Mesoporous Silica Nanoparticles Loaded with Surfactant: Low Temperature Magic Angle Spinning C-13 and Si-29 NMR Enhanced by Dynamic Nuclear Polarization

TitleMesoporous Silica Nanoparticles Loaded with Surfactant: Low Temperature Magic Angle Spinning C-13 and Si-29 NMR Enhanced by Dynamic Nuclear Polarization
Publication TypeJournal Article
Year of Publication2013
AuthorsLafon O, Thankamony ASL, Kobayashi T, Carnevale D, Vitzthum V, Slowing II, Kandel K, Vezin H, Amoureux JP, Bodenhausen G, Pruski M
Journal TitleJournal of Physical Chemistry C
Volume117
Pages1375-1382
Date Published01
Type of ArticleArticle
ISBN Number1932-7447
Accession NumberWOS:000314205100019
Keywordsinterface, MORPHOLOGY, proteins, relaxation, solid-state nmr, spectroscopy
Abstract

We show that dynamic nuclear polarization (DNP) can be used to enhance NMR signals of C-13 and Si-29 nuclei located in mesoporous organic/inorganic hybrid materials, at several hundreds of nanometers from stable radicals (TOTAPOL) trapped in the surrounding frozen disordered water. The approach is demonstrated using mesoporous silica nanoparticles (MSN), functionalized with 3-(N-phenylureido)propyl (PUP) groups, filled with the surfactant cetyltrimethylammonium bromide (CTAB). The DNP-enhanced proton magnetization is transported into the mesopores via H-1-H-1 spin diffusion and transferred to rare spins by cross-polarization, yielding signal enhancements epsilon(on/off) of around 8. When the CTAB molecules are extracted, so that the radicals can enter the mesopores, the enhancements increase to epsilon(on/off) approximate to 30 for both nuclei. A quantitative analysis of the signal enhancements in MSN with and without surfactant is based on a one-dimensional proton spin diffusion model. The effect of solvent deuteration is also investigated.

URL<Go to ISI>://WOS:000314205100019
DOI10.1021/jp310109s