13C-13C Correlations and Internuclear Distance Measurements with 2D-MELODRAMA
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- 作者：Harold C. Jarrell ; Dalian Lu ; and David J. Siminovitch
- 刊名：Journal of the American Chemical Society
- 出版年：1998
- 出版时间：October 14, 1998
- 年：1998
- 卷：120
- 期：40
- 页码：10453 - 10462
- 全文大小：139K
- 年卷期：v.120,no.40(October 14, 1998)
- ISSN：1520-5126
文摘
Under magic-angle spinning (MAS), the 2D-MELODRAMA pulse sequence reintroduces homonuclear dipolar couplings, thereby allowing internuclear correlations to be determined. The evolution of thedensity matrix under the average Hamiltonian established under the 2D-MELODRAMA pulse sequence hasbeen evaluated, and closed-form expressions for the dependence of cross-peak intensity as a function of thedipolar mixing time are presented. In the case of sodium proprionate-2-3-13C2 (>90% 13C) it is shown thatanalysis of cross-peak intensity vs mixing times allows estimates of dipolar coupling with an accuracycomparable with the 1D-MELODRAMA experiment. The potential for simultaneous multiple internuclearcorrelations and distance measurements in spin systems for which there is not a large difference in resonancefrequencies is illustrated with glucose-13C6 (36% uniformly labeled). It is shown that multiple correlations foreach ring carbon can be detected and good estimates of the corresponding internuclear distances can be extractedfrom analysis of cross-peak intensities as a function of the dipolar recoupling time.