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Full-Text Articles in Chemistry
Two-Dimensional Nuclear Magnetic Resonance Correlation Spectroscopy At Zero Field, Ming-Yuan Liao, Gerard S. Harbison
Two-Dimensional Nuclear Magnetic Resonance Correlation Spectroscopy At Zero Field, Ming-Yuan Liao, Gerard S. Harbison
Gerard Harbison Publications
Three methods for two-dimensional correlation nuclear magnetic resonance spectroscopy at zero field are discussed. All three involve coherence transfer via longitudinal polarization, double quantum coherence, or both in parallel. The double quantum pulse sequences exploit the spinor property of spin states. These sequences have been applied to connected Δm=1 transitions, as well as for the indirect detection of forbidden or nearly forbidden Δm.1 transitions.
Methylene-Only Subspectra In 13C Cpmas Using A New Double Quantum Filtering Sequence, Paola Rossi, Raju Subramanian, Gerard S. Harbison
Methylene-Only Subspectra In 13C Cpmas Using A New Double Quantum Filtering Sequence, Paola Rossi, Raju Subramanian, Gerard S. Harbison
Gerard Harbison Publications
Methodology for the assignment of 13C CPMAS spectra is still in its infancy. Previous methods of CPMAS spectral editing have utilized differences in the strength of the 13C–1H dipolar interaction or the rate and spin thermodynamics of crosspolarization from protons to carbon, to differentiate between quaternary, tertiary, and methylene carbons. We introduce a different approach, which is based on the fact that double-quantum coherence develops between the protons of a methylene group considerably faster than between most other proton spin pairs in an organic solid. We generate this coherence, filter it, convert it back to single …