Proton-detected 14N MAS NMR using homonuclear decoupled rotary resonance

Zhehong Gan (1) , Jean-Paul Amoureux (2) , Julien Trébosc (2)

1 National High Magnetic Field Laboratory
2 UCCS - Unité de Catalyse et Chimie du Solide - UMR 8181

A robust sensitivity-enhanced 1H/14N MAS HMQC experiment is described for proton-detected 14N NMR of solids. The sensitivity enhancement is achieved by using dipolar recoupling for coherence transfer with a so-called n = 2 rotary resonance. Rotary resonance occurs when a cw rf field matches certain ratios with the sample spinning frequency, n = ω1/ωr. The theory of rotary resonance for chemical shift anisotropy, heteronuclear and homonuclear dipolar interactions is presented in the irreducible representation. It is shown that the n = 2 rotary resonance decouples the homonuclear dipolar interactions while recoupling the heteronuclear dipolar interaction for proton-detected 14N NMR. The dipolar recoupling, T2′ lengthening, and 1H/14N HMQC experiment under the n = 2 rotary resonance are demonstrated.

Domaines: Matériaux

Zhehong Gan, Jean-Paul Amoureux, Julien Trébosc. Proton-detected 14N MAS NMR using homonuclear decoupled rotary resonance. Chemical Physics Letters, 2007, 435, pp.163-169. ⟨10.1016/j.cplett.2006.12.066⟩. ⟨hal-00133807⟩