Experimental study of resolution of proton chemical shifts in solids: Combined multiple pulse NMR and magic-angle spinning

Journal Article · Tue Jan 01 00:00:00 EST 1980 · J. Chem. Phys.; (United States)

DOI:https://doi.org/10.1063/1.438935· OSTI ID:5549150

Ryan, L M; Taylor, R E; Paff, A J; Gerstein, B C

High-resolution nuclear magnetic resonance spectra of protons in rigid, randomly oriented solids have been measured using combined homonuclear dipolar decoupling (via multiple pulse techniques) and attenuation of chemical shift anisotropies (via magic-angle sample spinning). Under those conditions, isotropic proton chemical shifts were recorded for a variety of chemical species, with individual linewidths varying from about 55 to 110 Hz (1--2 ppm). Residual line broadening was due predominately to (i) magnetic-field instability and inhomogeneity, (ii) unresolved proton--proton spin couplings, (iii) chemical shift dispersion, (iv) residual dipolar broadening, and (v) lifetime broadening under the multiple pulse sequences used. The magnitudes of those effects and the current limits of resolution for this experiment in our spectrometer have been investigated. The compounds studied included organic solids (4, 4'-dimethylbenzophenone, 2, 6-dimethylbenzoic acid, and aspirin), polymers (polystyrene and polymethylmethacrylate), and the vitrain portion of a bituminous coal.

• Research Organization: Ames Laboratory, U. S. Department of Energy, and Department of Chemistry, Iowa State University, Ames, Iowa 50011
• OSTI ID: 5549150
• Journal Information: J. Chem. Phys.; (United States), Vol. 72:1
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ACETYLSALICYLIC ACID
NMR SPECTRA
ORGANIC COMPOUNDS
POLYSTYRENE
ANISOTROPY
CHEMICAL SHIFT
LINE WIDTHS
RESOLUTION
ANALGESICS
CARBOXYLIC ACIDS
DRUGS
HYDROXY ACIDS
ORGANIC ACIDS
ORGANIC POLYMERS
PETROCHEMICALS
PETROLEUM PRODUCTS
PLASTICS
POLYMERS
POLYOLEFINS
POLYVINYLS
SPECTRA
400301* - Organic Chemistry- Chemical & Physicochemical Properties- (-1987)