Hetero- and Homonuclear Correlation Experiments Involving MQMAS

HETERO- AND HOMONUCLEAR CORRELATION EXPERIMENTS INVOLVING MQMAS 

MQMAS has further opened up vistas by making it possible to design high-resolution hetero- and homonuclear correlation experiments. These lead to connectivity information, distance measurements, and spectral editing. 

Connectivity information and spectral editing may be performed by combining crosspolarization (CP) and MQMAS. These include direct CP from a spin-j to the quadrupolar spin and subsequently its detection with MQMAS scheme. CP can be performed by polarizing either the CT of the quadrupolar nucleus followed by an inverse split- MQMAS scheme, allowing the incorporation of FAM pulses,or by directly polarizing the multiple-quantum transitions during the CP contact time. ° ° 

Another very important experiment for spectral editing is a heterocorrelation experiment combining MQMAS (in the indirect dimension) with CP. Introducing CP at the MQMAS echo position following a split-fj MQMAS scheme creates a spin-j detected spectra (in the dimension), which is modulated by the isotropic frequency of the quadrupolar nucleus in F. HETCOR has been demonstrated on Na- P pairs, on 2 A1- P pairs and lately on a- H pairs,where proton resolution during F was obtained with the wPMLGS multiple pulse decoupling technique.  

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Hetero- and Homonuclear Correlation Experiments Involving MQMAS... 

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