Heteronuclear dipolar correlation

B.J. Van Rossum, H. Foerster, H.J.M. de Groot, High-field and high-speed CP-MAS 13C NMR heteronuclear dipolar-correlation spectroscopy of sohds with frequency-switched Lee-Goldburg homonuclear decoupHng, J. Magn. Reson. 124 (1997) 516-519. 

Heteronuclear correlation (HETCOR) is an experiment establishing a correlation between the chemical shift of proton and that for another nucleus (i.e. C, P, Nor Si). The experiment relies on the heteronuclear dipolar interactions and uses a CP to transfer magnetization from protons to a rare spin.4,6 We have used 2D HETCOR experiment to characterize support/counter-cation/cluster interaction in the supported mesoporous catalysts.21... 

At the qualitative level, NMR studies devoted to this issue exploit heteronuclear dipolar recoupling to correlate resolved MAS NMR signals of the nuclear species associated with different network formers. This information comes from the dephasing of the observe nuclei in REDOR, TRAPDOR, or REAPDOR experiments, or from one- or two-dimensional correlation spectroscopy involving coherence transfer via TEDOR (transferred echo double resonance) or... 

General symmetry principles for rotor-synchronized pulse sequences in MAS solid-state NMR have been presented. The synunetry theory has been extended to the case of generalized Hartmann-Hahn sequences, in which rotor-synchronized r.f. irradiation is applied simultaneously to two isotopic spin species. The symmetry theory has been used to design pulse sequences which implement heteronuclear dipolar recoupling at the same time as decoupling homonuclear spin-spin interactions, and which also suppress CSAs. Experimental demonstrations of heteronuclear 2D correlation spectroscopy, heteronuclear MQ spectroscopy, and the estimation of intemuclear dipolar couplings have been given. 

An in-depth account of the effects of homonuclear couphngs and multiple heteronuclear couplings has been given for a recently published technique for H- C dipolar correlation in solids under very fast MAS, where the heteronuclear dipolar coupling is recoupled by means of REDOR n-pulse trains." The method bears similarities to well-known solution NMR techniques, which form the framework of a heteronuclear MQ experiment. The so-called... 

---