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Spectral Spin Diffusion Enhancement by Recoupling Quadrupolar Spins under Magic-Angle-Spinning

Spectral Spin Diffusion Enhancement by Recoupling Quadrupolar Spins under Magic-Angle-Spinning. Shangwu Ding , Shun-liang Tseng, Jian-ming Chen, Hsuan-sheng Huang

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Spectral Spin Diffusion Enhancement by Recoupling Quadrupolar Spins under Magic-Angle-Spinning

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  1. Spectral Spin Diffusion Enhancement by Recoupling Quadrupolar Spins under Magic-Angle-Spinning Shangwu Ding , Shun-liang Tseng, Jian-ming Chen, Hsuan-sheng Huang Department of Chemistry and Center for Nanoscience and Nanotechnology, National Sun Yat-sen University, 70 Lien-Hai Road, Kaohsiung, Taiwan 80424, Republic of China

  2. What MQMAS Tells And Does Not Tell Z Three Principal Values—Yes! Plus Isotropic Chemical Shift Orientation—No For Powder Samples Used V11 V33 V22 Y X

  3. What MQMAS May Tell The Relative OrientationBetween Two Quadrupolar Tensors ZA V33,A ZB V11,B V11,A YA V33,B V22,A V22,B YB XA XB

  4. Generic Spin Diffusion/Exchange Pulse Sequence P1 t1 P2tm P3t2 Evolution of Spin A(B) Evolution of Spin B(A)

  5. Two Spin-3/2 MQMAS-Spin Diffusion Spectrum MQMAS Peaks (3/2,-3/2)(1/2,-1/2) Cross Peaks

  6. A Real Pulse • Finite Width • Finite Power • Phase/Amplitude Imperfections t

  7. MAS Suppressed Spin Diffusion

  8. Recoupling Schemes • Rotational Resonance Method • Rotary Resonance Method • Shaped Pulse Method: A. Applied to Quadrupolar Channel B. Applied to Proton Channel C. Applied to Both Channel To maximize polarization transfer during mixing time by optimizing recoupling pulses.

  9. Using An Actual Pulse Sequence F1 F2

  10. Using An Actual Pulse Sequence F1 Intensity F2

  11. Using An Actual Pulse Sequence F1 F2

  12. Using An Actual Pulse Sequence F2 Intensity F1

  13. Sodium 3QC-1QC Cross Peak (Na2HPO4, tm=200 ms) “Normal” Scheme Experimental QCC=2.13, 1.37 MHz, Eta=0.7,0.2

  14. Scheme 1 QCC=2.13, 1.37 MHz, Eta=0.7,0.2 Sodium 3QC-1QC Cross Peak (Na2HPO4, tm=200ms)

  15. Sodium 3QC-1QC Cross Peak (Na2HPO4, tm=100 ms) Scheme 2 QCC=2.13, 1.37 MHz, Eta=0.7,0.2

  16. QCC=2.13, 1.37 MHz, Eta=0.2,0.1 Sodium 3QC-1QC Cross Peak (Na2HPO4, tm=160 ms) Scheme 3

  17. Other Work • Pulse Sequence Simplification/Optimization • 3D Exchange-Correlation • Spin-5/2, 7/2, 9/2 Systems • More Versatile Applications

  18. A Possible Modified Pulse Sequence t1 t2 Soft Pulses For Accelerating Equilibration

  19. 3D Pulse Sequence For Spin Diffusion k1t1 k2t1 tm k1t2 k2t2 t3

  20. 3D MQMAS Exchange Spectrum F2 F2 F1-F2 Proj. F1 F3 F1 F2 Removing Diagonal Peaks F1

  21. Applications To Biological Systems • Relative Orientation Between Quadrupolar Tensors in Disodium ATP Relative Orientation Between Quadrupolar Tensors in Zinc Metalloproteins

  22. Conclusions • Spectral Spin Diffusion Of Half-Integer Quadrupolar Spins Can Be Enhanced With Recoupling Pulses During Mixing Time • The Principal Components Of The EFG Tensors And The Relative Orientations of EFG Tensors Of Coupled Spins Can Be Determined • Many Extensions and Applications Are Feasible

  23. Acknowledgment:National Science Council & Ministry of Education, Taiwan, ROC. References: • [1] S. Ding, C.A.McDowell, Mol. Phys. 85,283(1995). • [2] L. Frydman, J.S.harwood, J. Am. Chem. Soc. 117,5367(1995). • [3] N.G.Dowell, S.E.Askbrook, J. McManus, S. Wimperis, J. Am. Chem. Soc. 123,8135 (2001). • [4] M.Baldus, D.Rovnyak, R. G. Griffin, J. Chem. Phys. 112,5902 (2000). • [5] S. Ding, S.L.Tseng, J.M.Chen, H.S.Huang, submitted.

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