Measurement of NMR Cross-Polarization (CP) Rate Constants in the Slow CP Regime: Relevance to Structure Determinations of Zeolite−Sorbate and Other Complexes by CP Magic-Angle Spinning NMR

When analyzing I --> S variable contact time cross-polarization (CP) curves, the spin dynamics are usually assumed to be describable in the "fast CP regime" in which the growth of the S spin magnetization is governed by the rate of cross polarization while its decay is governed by the rate of I spin T1rho relaxation. However, in the investigation of the structures of zeolite-sorbate and other complexes by polarization transfer this will not …