title: Chemical shift powder spectra enhanced by multiple-contact cross-polarization under slow magic-angle spinning.
abstract: A simple multiple-contact cross-polarization (CP) scheme is applied to a powder sample of ferrocene and β-calcium formate under static and magic-angle spinning (MAS) conditions. The method is described analytically through the density matrix formalism. We show that multiple equilibrations-re-equilibrations with the proton spin bath improves the polarization transfer efficiency at short contact times and provides higher signal enhancements than state-of-the art techniques such as adiabatic passage through the Hartmann-Hahn condition CP (APHH-CP) when MAS is applied. The resulting chemical shift powder spectra then are identical to the ones obtained by using ROtor-Directed Exchange of Orientations CP (APHH-RODEO-CP) with intensity gains of a factor 1.1-1.3.
authors: Institut de Chimie, UMR CNRS, Université de Strasbourg, France.
authors: Jésus
authors: J
authors: Raya
authors: Barbara
authors: B
authors: Perrone
authors: Jérôme
authors: J
authors: Hirschinger
mesh_terms: D000465:Algorithms; D005296:Ferrous Compounds / Q000737:chemistry*; D005561:Formates / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D000075163:Metallocenes; D011208:Powders / Q000737:chemistry*; D013113:Spin Labels
chemical_list: D005296:Ferrous Compounds; D005561:Formates; D000075163:Metallocenes; D011208:Powders; D013113:Spin Labels; C030544:formic acid; C004998:ferrocene