AsymPol-TEKs as efficient polarizing agents for MAS-DNP in glass matrices of non-aqueous solvents. Harrabi, R., Halbritter, T., Alarab, S., Chatterjee, S., Wolska-Pietkiewicz, M., Damodaran, K. K., Van Tol, J., Lee, D., Paul, S., Hediger, S., Sigurdsson, S. T., Mentink-Vigier, F., & De Paëpe, G. Physical Chemistry Chemical Physics, 26(6):5669–5682, 2024.
AsymPol-TEKs as efficient polarizing agents for MAS-DNP in glass matrices of non-aqueous solvents [link]Paper  doi  abstract   bibtex   
Two polarizing agents from the AsymPol family, AsymPol-TEK and cAsymPol-TEK (methyl-free version) are introduced for MAS-DNP applications in non-aqueous solvents. , Two polarizing agents from the AsymPol family, AsymPol-TEK and cAsymPol-TEK (methyl-free version) are introduced for MAS-DNP applications in non-aqueous solvents. The performance of these new biradicals is rationalized in detail using a combination of electron paramagnetic resonance spectroscopy, density functional theory, molecular dynamics and quantitative MAS-DNP spin dynamics simulations. By slightly modifying the experimental protocol to keep the sample temperature low at insertion, we are able to obtain reproducable DNP-NMR data with 1,1,2,2-tetrachloroethane (TCE) at 100 K, which facilitates optimization and comparison of different polarizing agents. At intermediate magnetic fields, AsymPol-TEK and cAsymPol-TEK provide 1.5 to 3-fold improvement in sensitivity compared to TEKPol, one of the most widely used polarizing agents for organic solvents, with significantly shorter DNP build-up times of ∼1 s and ∼2 s at 9.4 and 14.1 T respectively. In the course of the work, we also isolated and characterized two diastereoisomers that can form during the synthesis of AsymPol-TEK; their difference in performance is described and discussed. Finally, the advantages of the AsymPol-TEKs are demonstrated by recording 2D 13 C– 13 C correlation experiments at natural 13 C-abundance of proton-dense microcrystals and by polarizing the surface of ZnO nanocrystals (NCs) coated with diphenyl phosphate ligands. For those experiments, cAsymPol-TEK yielded a three-fold increase in sensitivity compared to TEKPol, corresponding to a nine-fold time saving.
@article{harrabi_asympol-teks_2024,
	title = {{AsymPol}-{TEKs} as efficient polarizing agents for {MAS}-{DNP} in glass matrices of non-aqueous solvents},
	volume = {26},
	issn = {1463-9076, 1463-9084},
	url = {http://xlink.rsc.org/?DOI=D3CP04271E},
	doi = {10.1039/D3CP04271E},
	abstract = {Two polarizing agents from the AsymPol family, AsymPol-TEK and cAsymPol-TEK (methyl-free version) are introduced for MAS-DNP applications in non-aqueous solvents.
          , 
            
              Two polarizing agents from the AsymPol family, AsymPol-TEK and cAsymPol-TEK (methyl-free version) are introduced for MAS-DNP applications in non-aqueous solvents. The performance of these new biradicals is rationalized in detail using a combination of electron paramagnetic resonance spectroscopy, density functional theory, molecular dynamics and quantitative MAS-DNP spin dynamics simulations. By slightly modifying the experimental protocol to keep the sample temperature low at insertion, we are able to obtain reproducable DNP-NMR data with 1,1,2,2-tetrachloroethane (TCE) at 100 K, which facilitates optimization and comparison of different polarizing agents. At intermediate magnetic fields, AsymPol-TEK and cAsymPol-TEK provide 1.5 to 3-fold improvement in sensitivity compared to TEKPol, one of the most widely used polarizing agents for organic solvents, with significantly shorter DNP build-up times of ∼1 s and ∼2 s at 9.4 and 14.1 T respectively. In the course of the work, we also isolated and characterized two diastereoisomers that can form during the synthesis of AsymPol-TEK; their difference in performance is described and discussed. Finally, the advantages of the AsymPol-TEKs are demonstrated by recording 2D
              13
              C–
              13
              C correlation experiments at natural
              13
              C-abundance of proton-dense microcrystals and by polarizing the surface of ZnO nanocrystals (NCs) coated with diphenyl phosphate ligands. For those experiments, cAsymPol-TEK yielded a three-fold increase in sensitivity compared to TEKPol, corresponding to a nine-fold time saving.},
	language = {en},
	number = {6},
	urldate = {2024-04-08},
	journal = {Physical Chemistry Chemical Physics},
	author = {Harrabi, Rania and Halbritter, Thomas and Alarab, Shadi and Chatterjee, Satyaki and Wolska-Pietkiewicz, Malgorzata and Damodaran, Krishna K. and Van Tol, Johan and Lee, Daniel and Paul, Subhradip and Hediger, Sabine and Sigurdsson, Snorri Th. and Mentink-Vigier, Frederic and De Paëpe, Gaël},
	year = {2024},
	pages = {5669--5682},
}

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