Spectral Spin Diffusion Enhancement by Recoupling Quadrupolar Spins under Magi

c-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

What MQMAS Tells And Does Not TellThree Principal Values—Yes! Plus Isotropic Chemical ShiftThree Principal Values—Yes! Plus Isotropic Chemical Shift

VV3333VV2222

VV1111

XX

YY

ZZ

Orientation—No For Powder Samples UsedOrientation—No For Powder Samples Used

The The Relative OrientationRelative Orientation Between Two Between Two Quadrupolar TensorsQuadrupolar Tensors

What MQMAS May Tell

VV33,B33,B

YYBB

VV33,A33,A

VV11,A11,A

XXAA

YYAA

VV11,B11,B

VV22,A22,A

VV22,B22,B

XXB B

ZZAAZZBB

Generic Spin Diffusion/Exchange Pulse Sequence

PP1 1 tt11 P P22 ttmm P P33 tt22

Evolution of Spin A(B)Evolution of Spin A(B) Evolution of Spin Evolution of Spin B(A)B(A)

Two Spin-3/2 MQMAS-Spin Diffusion Spectrum

MQMAS PeaksMQMAS PeaksCross PeaksCross Peaks

(3/2,-3/2)(3/2,-3/2)(1/2,-1/2)(1/2,-1/2)(3/2,-3/2)(3/2,-3/2)(1/2,-1/2)(1/2,-1/2)

)45,0,90(),,(

.1.0,4.1

,5.0,5.2

0

22,

11,

oo

q

q

MHzC

MHzC

)45,0,90(),,(

.1.0,4.1

,5.0,5.2

0

22,

11,

oo

q

q

MHzC

MHzC

A Real Pulse

Finite WidthFinite Width Finite PowerFinite Power Phase/Amplitude Imperfections Phase/Amplitude Imperfections

tt

MAS Suppressed Spin Diffusion

rIID kM /1 rIID kM /1

2,1

2

)(1

)(2 ||22

12

12

m

dmm

mBASD AR

Dr

DrD

2,1

2

)(1

)(2 ||22

12

12

m

dmm

mBASD AR

Dr

DrD

2,1m

timdm

DSS

reAH

2,1m

timdm

DSS

reAH

Recoupling Schemes Rotational Resonance MethodRotational Resonance Method Rotary Resonance MethodRotary Resonance Method Shaped Pulse Method:Shaped Pulse Method:

A. Applied to Quadrupolar ChannelA. Applied to Quadrupolar Channel

B. Applied to Proton ChannelB. Applied to Proton Channel

C. Applied to Both ChannelC. Applied to Both Channel

xSxIm

timdm

DSS StIteAHH r )()( 11

2,11

xSxI

m

timdm

DSS StIteAHH r )()( 11

2,11

To maximize polarization transfer during mixing timeTo maximize polarization transfer during mixing time

by optimizing recoupling pulses.by optimizing recoupling pulses.

Using An Actual Pulse Sequence

FF22

FF11kHz

sPsPsP

MHzC

MHzC

oo

q

q

80

,3,3,9

)20,90,40(),,(

.4.0,2.1

,3.0,5.2

1

111

0

22,

11,

kHz

sPsPsP

MHzC

MHzC

oo

q

q

80

,3,3,9

)20,90,40(),,(

.4.0,2.1

,3.0,5.2

1

111

0

22,

11,

F1F1

IntensityIntensity

F2 F2

Using An Actual Pulse Sequence

FF22

FF11

Using An Actual Pulse Sequence

kHz

sPsPsP

MHzC

MHzC

oo

q

q

80

,3,3,9

)40,30,60(),,(

.6.0,8.2

,3.0,0.4

1

111

0

22,

11,

kHz

sPsPsP

MHzC

MHzC

oo

q

q

80

,3,3,9

)40,30,60(),,(

.6.0,8.2

,3.0,0.4

1

111

0

22,

11,

F1F1

Intensi tyI ntens it y

F2 F2

Using An Actual Pulse Sequence

Experimental

Sodium 3QC-1QC Cross Peak (Na2HPO4, tm=200 ms)

QCC=2.13, 1.37 MHz,

Eta=0.7,0.2 .200,55

4,12,12

)40,30,60(),,(

.2.0,37.1

,7.0,13.2

1

111

0

22,

11,

mstkHz

sPsPsP

MHzC

MHzC

m

oo

q

q

.200,55

4,12,12

)40,30,60(),,(

.2.0,37.1

,7.0,13.2

1

111

0

22,

11,

mstkHz

sPsPsP

MHzC

MHzC

m

oo

q

q

““Normal” SchemeNormal” Scheme

Sodium 3QC-1QC Cross Peak (Na2HPO4, tm=200ms)

QCC=2.13, 1.37 MHz,

Eta=0.7,0.2 .200,55

4,8,8

)40,30,60(),,(

.2.0,37.1

,7.0,13.2

1

111

0

22,

11,

mstkHz

sPsPsP

MHzC

MHzC

m

oo

q

q

.200,55

4,8,8

)40,30,60(),,(

.2.0,37.1

,7.0,13.2

1

111

0

22,

11,

mstkHz

sPsPsP

MHzC

MHzC

m

oo

q

q

Scheme 1Scheme 1

Sodium 3QC-1QC Cross Peak (Na2HPO4, tm=100 ms)

QCC=2.13, 1.37 MHz,

Eta=0.7,0.2

.100,55

4,12,12

)40,30,60(),,(

.2.0,37.1

,7.0,13.2

1

111

0

22,

11,

mstkHz

sPsPsP

MHzC

MHzC

m

oo

q

q

.100,55

4,12,12

)40,30,60(),,(

.2.0,37.1

,7.0,13.2

1

111

0

22,

11,

mstkHz

sPsPsP

MHzC

MHzC

m

oo

q

q

Scheme 2Scheme 2

QCC=2.13, 1.37 MHz,

Eta=0.2,0.1

Sodium 3QC-1QC Cross Peak (Na2HPO4, tm=160 ms)

.160,55

4,12,12

)40,30,60(),,(

.2.0,37.1

,7.0,13.2

1

111

0

22,

11,

mstkHz

sPsPsP

MHzC

MHzC

m

oo

q

q

.160,55

4,12,12

)40,30,60(),,(

.2.0,37.1

,7.0,13.2

1

111

0

22,

11,

mstkHz

sPsPsP

MHzC

MHzC

m

oo

q

q

Scheme 3Scheme 3

Other Work

Pulse Sequence Simplification/OptimizationPulse Sequence Simplification/Optimization 3D Exchange-Correlation3D Exchange-Correlation Spin-5/2, 7/2, 9/2 SystemsSpin-5/2, 7/2, 9/2 Systems More Versatile Applications More Versatile Applications

A Possible Modified Pulse Sequence

tt11 t t22

Soft Pulses For Accelerating Equilibration Soft Pulses For Accelerating Equilibration

3D Pulse Sequence For Spin Diffusion

kk11tt11 k k22tt11 t tmm k k11tt22 k k22tt22 t t33

3D MQMAS Exchange Spectrum

F2F2

F3F3F1F1 F2F2

F2F2

F1F1

F1F1

RemovingRemoving

Diagonal PeaksDiagonal Peaks

FF11-F-F2 2 Proj.Proj.

Applications To Biological Systems

Relative Orientation Between Quadrupolar Relative Orientation Between Quadrupolar Tensors in Disodium ATP Tensors in Disodium ATP

Relative Orientation Between Quadrupolar Relative Orientation Between Quadrupolar Tensors in Zinc Metalloproteins Tensors in Zinc Metalloproteins

Conclusions

Spectral Spin Diffusion Of Half-Integer Spectral Spin Diffusion Of Half-Integer Quadrupolar Spins Can Be Enhanced With Quadrupolar Spins Can Be Enhanced With Recoupling Pulses During Mixing TimeRecoupling Pulses During Mixing Time

The Principal Components Of The EFG Tensors The Principal Components Of The EFG Tensors And The Relative Orientations of EFG Tensors Of And The Relative Orientations of EFG Tensors Of Coupled Spins Can Be DeterminedCoupled Spins Can Be Determined

Many Extensions and Applications Are FeasibleMany Extensions and Applications Are Feasible

Acknowledgment:National Science Council & Ministry of Education, Taiwan, ROC.

References:References: [1] S. Ding, C.A.McDowell, Mol. Phys. 85,283(1995).[1] S. Ding, C.A.McDowell, Mol. Phys. 85,283(1995). [2] L. Frydman, J.S.harwood, J. Am. Chem. Soc. [2] L. Frydman, J.S.harwood, J. Am. Chem. Soc.

117,5367(1995).117,5367(1995). [3] N.G.Dowell, S.E.Askbrook, J. McManus, S. Wimperis, [3] N.G.Dowell, S.E.Askbrook, J. McManus, S. Wimperis,

J. Am. Chem. Soc. 123,8135 (2001).J. Am. Chem. Soc. 123,8135 (2001). [4] M.Baldus, D.Rovnyak, R. G. Griffin, J. Chem. Phys. [4] M.Baldus, D.Rovnyak, R. G. Griffin, J. Chem. Phys.

112,5902 (2000).112,5902 (2000). [5] S. Ding, S.L.Tseng, J.M.Chen, H.S.Huang, submitted.[5] S. Ding, S.L.Tseng, J.M.Chen, H.S.Huang, submitted.