Proton-detected solid-state NMR spectroscopy of spin-1/2 nuclei with large chemical shift anisotropy.

摘要: Abstract Constant-time (CT) dipolar heteronuclear multiple quantum coherence (D-HMQC) has previously been demonstrated as a method for proton detection of high-resolution wideline NMR spectra spin-1/2 nuclei with large chemical shift anisotropy (CSA). However, 1H transverse relaxation and t1-noise often reduce the sensitivity D-HMQC experiments, preventing theoretical gains in provided by from being realized. Here we demonstrate series improved pulse sequences under fast MAS, 195Pt SSNMR experiments on cisplatin an example. First, t1-incrementation protocol dubbed Arbitrary Indirect Dwell (AID) is demonstrated. AID allows use arbitrary, rotor asynchronous t1-increments, but removes constant time period CT D-HMQC, resulting reducing losses. Next, show that short high-power adiabatic pulses (SHAPs), which efficiently invert broad MAS sideband manifolds, can be effectively incorporated into detected symmetry-based resonance echo double (S-REDOR) eliminated (TONE) experiments. The S-REDOR SHAPs provide approximately dephasing, compared to rectangular inversion pulses. We lastly resolution further enhanced swept excitation well magic angle turning (aMAT).