Isotropic/Anisotropic NMR Editing by Resolution‐Enhanced NMR Spectroscopy

Abstract

Modern resolution-enhanced NMR techniques can monitor the in situ discrimination of co-existing isotropic and anisotropic contributions of small molecules dissolved in weakly aligning PMMA/CDCl3 media. The simultaneous sign-sensitive determination of accurate Δδ ( H), Δδ ( C) and/or isotropic J and anisotropic T coupling constants (and consequently H- C residual dipolar couplings and H/ C residual chemical shift anisotropies) can be performed from spectral-aliased heteronuclear single-quantum correlation spectra.

“One-Shot” Measurement of Residual Chemical Shift Anisotropy Using Poly-γ-benzyl-l-glutamate as an Alignment Medium

“…Recently, a method employing self-assembling polypeptides was reported that allowed for the measurement of the 13 C NMR spectrum in an isotropic state, and then after an equilibration time ranging from hours to weeks, a complementary 13 C spectrum could be acquired in an aligned condition . Work in the Gil lab demonstrated that RDCs can be measured in a single experiment when using compressed gels due to the fact that after a certain degree of compression, the gels buckle and generate pockets of isotropic solvent, which are never eliminated. , The amount of buckling depends on the degree of polymeric cross-linking and the length of the gel …”

Polyarylisocyanides Derived from an Alkyne-Pd(II) Catalyst as Robust Alignment Media with Excellent Enantiodiscimination

“…Before acquiring the RDC data, the quadrupolar splitting of CD 2 Cl 2 in each sample was measured to ensure similar ordering strength among the samples. In addition to measuring the 1 D CH data using the aforementioned CLIP-HSQC experiment, we also extracted the same data using the F1 dimension J -scaled BIRD HSQC (JSB-HSQC) pulse sequence, which is better suited for more complex compounds containing several methylene groups. − …”