Campus Units

Chemistry, Ames Laboratory

Document Type

Article

Publication Version

Published Version

Publication Date

2013

Journal or Book Title

Journal of Physical Chemistry C

Volume

117

Issue

3

First Page

1375

Last Page

1382

DOI

10.1021/jp310109s

Abstract

We show that dynamic nuclear polarization (DNP) can be used to enhance NMR signals of13C and 29Si 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 1H–1H spin diffusion and transferred to rare spins by cross-polarization, yielding signal enhancements εon/off of around 8. When the CTAB molecules are extracted, so that the radicals can enter the mesopores, the enhancements increase to εon/off ≈ 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.

Comments

Reprinted (adapted) with permission from Journal of Physical Chemistry C 117 (2013): 1375, doi:10.1021/jp310109s. Copyright 2013 American Chemical Society.

Copyright Owner

American Chemical Society

Language

en

File Format

application/pdf

Included in

Chemistry Commons

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