title: Multiple resonance heteronuclear decoupling under MAS: dramatic increase of spectral resolution at moderate magnetic field and MAS frequencies.
abstract: The effects of multiple-resonance heteronuclear decoupling under magic angle spinning (MAS) on the resolution of one-dimensional (19)F and (31)P and various two-dimensional MAS NMR spectra and on the residual non-refocusable coherence lifetimes in fluorinated aluminophosphate AlPO(4)-CJ2, i.e. a compound that contains numerous highly abundant nuclei but no homonuclear spin bath, has been investigated. The design of the four-channel ((1)H, (19)F, (27)Al, (31)P) MAS probe used for this study is first described. (1)H and (1)H-(27)Al double-resonance decouplings allows lengthening the optimized transverse relaxation T(2)(opt) and increasing the resolution in the (19)F and (31)P dimensions. Under the application of multi-nuclear decoupling, a two-dimensional (19)F-(31)P CP-HETCOR correlation spectrum for AlPO(4)-CJ2 is recorded with unprecedented high-resolution in the two dimensions. Moreover, because (1)H-decoupling increases the (19)F T(2)(opt), it has been applied during the entire duration of the 2D NMR experiments, allowing the direct use of residual small interactions to generate (19)F-(19)F and (19)F-(27)Al 2D NMR correlation spectra in AlPO(4)-CJ2.
authors.affiliation: Tectospin, Institut Lavoisier de Versailles (ILV), UMR CNRS 8180, Université de Versailles Saint-Quentin-en-Yvelines, 45 Avenue des États-Unis, 78035 Versailles cedex, France. charlotte.martineau@chimie.uvsq.fr
authors.forename: Charlotte
authors.initials: C
authors.lastname: Martineau
authors.forename: Franck
authors.initials: F
authors.lastname: Engelke
authors.forename: Francis
authors.initials: F
authors.lastname: Taulelle
mesh_terms: D000465:Algorithms; D017607:Aluminum Compounds / Q000737:chemistry; D004574:Electromagnetic Fields; D005461:Fluorine / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D010710:Phosphates / Q000737:chemistry; D014961:X-Ray Diffraction
chemical_list: D017607:Aluminum Compounds; D010710:Phosphates; D005461:Fluorine; C012714:aluminum phosphate