Document Detail


Solvent-free dynamic nuclear polarization of amorphous and crystalline ortho-terphenyl.
MedLine Citation:
PMID:  23421391     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Dynamic nuclear polarization (DNP) of amorphous and crystalline ortho-terphenyl (OTP) in the absence of glass forming agents is presented in order to gauge the feasibility of applying DNP to pharmaceutical solid-state nuclear magnetic resonance experiments and to study the effect of intermolecular structure, or lack thereof, on the DNP enhancement. By way of (1)H-(13)C cross-polarization, we obtained a DNP enhancement (ε) of 58 for 95% deuterated OTP in the amorphous state using the biradical bis-TEMPO terephthalate (bTtereph) and ε of 36 in the crystalline state. Measurements of the (1)H T1 and electron paramagnetic resonance experiments showed the crystallization process led to phase separation of the polarization agent, creating an inhomogeneous distribution of radicals within the sample. Consequently, the effective radical concentration was decreased in the bulk OTP phase, and long-range (1)H-(1)H spin diffusion was the main polarization propagation mechanism. Preliminary DNP experiments with the glass-forming anti-inflammation drug, indomethacin, showed promising results, and further studies are underway to prepare DNP samples using pharmaceutical techniques.
Authors:
Ta-Chung Ong; Melody L Mak-Jurkauskas; Joseph J Walish; Vladimir K Michaelis; Björn Corzilius; Albert A Smith; Andrew M Clausen; Janet C Cheetham; Timothy M Swager; Robert G Griffin
Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't     Date:  2013-03-04
Journal Detail:
Title:  The journal of physical chemistry. B     Volume:  117     ISSN:  1520-5207     ISO Abbreviation:  J Phys Chem B     Publication Date:  2013 Mar 
Date Detail:
Created Date:  2013-03-14     Completed Date:  2013-08-28     Revised Date:  2014-02-27    
Medline Journal Info:
Nlm Unique ID:  101157530     Medline TA:  J Phys Chem B     Country:  United States    
Other Details:
Languages:  eng     Pagination:  3040-6     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
Crystallization
Electron Spin Resonance Spectroscopy
Magnetic Resonance Spectroscopy
Terphenyl Compounds / chemistry*
Grant Support
ID/Acronym/Agency:
EB002026/EB/NIBIB NIH HHS; EB002804/EB/NIBIB NIH HHS; GM095843/GM/NIGMS NIH HHS; R01 GM095843/GM/NIGMS NIH HHS
Chemical
Reg. No./Substance:
0/Terphenyl Compounds
Comments/Corrections

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