TOTAPOL: A Biradical Polarizing Agent for Dynamic Nuclear Polarization Experiments in Aqueous Media

@article{citeulike:1188217, abstract = {Abstract: In a previous publication, we described the use of biradicals, in that case two TEMPO molecules tethered by an ethylene glycol chain of variable length, as polarizing agents for microwave driven dynamic nuclear polarization (DNP) experiments. The use of biradicals in place of monomeric paramagnetic centers such as TEMPO yields enhancements that are a factor of approximately 4 larger ( ~ 175 at 5 T and 90 K) and concurrently the concentration of the polarizing agent is a factor of 4 smaller (10 mM electron spins), reducing the residual electron nuclear dipole broadening. In this paper we describe the synthesis and characterization by EPR and DNP/NMR of an improved polarizing agent 1-(TEMPO-4-oxy)-3-(TEMPO-4-amino)propan-2-ol (TOTAPOL). Under the same experimental conditions and using 2.5 mm magic angle rotors, this new biradical yields larger enhancements ( ~ 290) at lower concentrations (6 mM electron spins) and has the additional important property that it is compatible with experiments in aqueous media, including salt solutions commonly used in the study of proteins and nucleic acids.}, address = {Contribution from the Francis Bitter Magnet Laboratory and Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139}, author = {Song, C. and Hu, K. N. and Joo, C. G. and Swager, T. M. and Griffin, R. G. }, citeulike-article-id = {1188217}, doi = {10.1021/ja061284b}, journal = {J. Am. Chem. Soc.}, keywords = {dnp, mas, tempo}, month = {September}, number = {35}, pages = {11385--11390}, posted-at = {2007-03-26 16:07:02}, priority = {2}, title = {TOTAPOL: A Biradical Polarizing Agent for Dynamic Nuclear Polarization Experiments in Aqueous Media}, url = {http://dx.doi.org/10.1021/ja061284b}, volume = {128}, year = {2006} }

TY - JOUR ID - citeulike:1188217 L3 - citeulike-article-id:1188217 TI - TOTAPOL: A Biradical Polarizing Agent for Dynamic Nuclear Polarization Experiments in Aqueous Media JF - J. Am. Chem. Soc. VL - 128 IS - 35 SP - 11385 EP - 11390 AD - Contribution from the Francis Bitter Magnet Laboratory and Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 N2 - Abstract: In a previous publication, we described the use of biradicals, in that case two TEMPO molecules tethered by an ethylene glycol chain of variable length, as polarizing agents for microwave driven dynamic nuclear polarization (DNP) experiments. The use of biradicals in place of monomeric paramagnetic centers such as TEMPO yields enhancements that are a factor of approximately 4 larger ( ~ 175 at 5 T and 90 K) and concurrently the concentration of the polarizing agent is a factor of 4 smaller (10 mM electron spins), reducing the residual electron nuclear dipole broadening. In this paper we describe the synthesis and characterization by EPR and DNP/NMR of an improved polarizing agent 1-(TEMPO-4-oxy)-3-(TEMPO-4-amino)propan-2-ol (TOTAPOL). Under the same experimental conditions and using 2.5 mm magic angle rotors, this new biradical yields larger enhancements ( ~ 290) at lower concentrations (6 mM electron spins) and has the additional important property that it is compatible with experiments in aqueous media, including salt solutions commonly used in the study of proteins and nucleic acids. KW - dnp KW - mas KW - tempo AU - Song, C AU - Hu, KN AU - Joo, CG AU - Swager, TM AU - Griffin, RG PY - 2006/09/06/ UR - http://dx.doi.org/10.1021/ja061284b ER -