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Author Zhang, Rongchun ♦ Ramamoorthy, Ayyalusamy ♦ Nishiyama, Yusuke
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY ♦ ALANINE-L ♦ ALLOCATIONS ♦ ANISOTROPY ♦ CARBON ♦ CARBON 13 ♦ CHEMICAL SHIFT ♦ COUPLINGS ♦ EFFICIENCY ♦ HISTIDINE ♦ HYDROGEN 1 ♦ INTERACTIONS ♦ KHZ RANGE ♦ MAGNETIZATION ♦ POLARIZATION ♦ PROTONS ♦ PULSES ♦ RESONANCE ♦ SOLIDS ♦ SPECTRA
Abstract A proton-detected 3D {sup 1}H/{sup 13}C/{sup 1}H chemical shift correlation experiment is proposed for the assignment of chemical shift resonances, identification of {sup 13}C-{sup 1}H connectivities, and proximities of {sup 13}C-{sup 1}H and {sup 1}H-{sup 1}H nuclei under ultrafast magic-angle-spinning (ultrafast-MAS) conditions. Ultrafast-MAS is used to suppress all anisotropic interactions including {sup 1}H-{sup 1}H dipolar couplings, while the finite-pulse radio frequency driven dipolar recoupling (fp-RFDR) pulse sequence is used to recouple dipolar couplings among protons and the insensitive nuclei enhanced by polarization transfer technique is used to transfer magnetization between heteronuclear spins. The 3D experiment eliminates signals from non-carbon-bonded protons and non-proton-bonded carbons to enhance spectral resolution. The 2D (F1/F3) {sup 1}H/{sup 1}H and 2D {sup 13}C/{sup 1}H (F2/F3) chemical shift correlation spectra extracted from the 3D spectrum enable the identification of {sup 1}H-{sup 1}H proximity and {sup 13}C-{sup 1}H connectivity. In addition, the 2D (F1/F2) {sup 1}H/{sup 13}C chemical shift correlation spectrum, incorporated with proton magnetization exchange via the fp-RFDR recoupling of {sup 1}H-{sup 1}H dipolar couplings, enables the measurement of proximities between {sup 13}C and even the remote non-carbon-bonded protons. The 3D experiment also gives three-spin proximities of {sup 1}H-{sup 1}H-{sup 13}C chains. Experimental results obtained from powder samples of L-alanine and L-histidine ⋅ H{sub 2}O ⋅ HCl demonstrate the efficiency of the 3D experiment.
ISSN 00219606
Educational Use Research
Learning Resource Type Article
Publisher Date 2015-10-28
Publisher Place United States
Journal Journal of Chemical Physics
Volume Number 143
Issue Number 16


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