Cross polarization and magic angle sample spinning NMR spectra of model organic compounds. 2. Molecules of low or remote protonation

Journal Article · Wed Apr 20 00:00:00 EST 1983 · J. Am. Chem. Soc.; (United States)

DOI:https://doi.org/10.1021/ja00346a007· OSTI ID:5826439

Alemany, L B; Grant, D M; Pugmire, R J; Alger, T D; Zilm, K W

Cross polarization/magic angle sample spinning (CP/MAS)/sup 13/C NMR spectra were obtained at various contact times on five solid organic compounds containing carbon atoms far from intramolecular protons or containing very few hydrogen atoms. Carbon atoms four or more bonds fromthe nearest intramolecular proton cannot be fully polarized before T/sub 1p/(H) effects begin to dominate the proton magnetization. Rapid molecular motion aggrevates the problem because of motional attenuation of the dipolar interaction. Computer-fitted T/sub CH/ and T/sub 1p/(H) parameters are consistent with these experimental results. The simple theories of cross polarization account for incomplete polarization in these cases. In 1,2:4,5-benzenetetracarboxylic dianhydride, C/sub 10/H/sub 2/O/sub 6/, the relative aromatic and carbonyl signal intensities are only 5% from the ideal values on the basis of atomic ratios, but absolute intensities can be seriously reduced. In general, CP/MAS NMR provides a convenient and useful quantitative method for studying diamagnetic, organic solids of low molecular weight that is competitive to other physical methods even for molecules of low or remote protonation.

• Research Organization: Univ. of Utah, Salt Lake City
• DOE Contract Number: AC02-78ER05006
• OSTI ID: 5826439
• Journal Information: J. Am. Chem. Soc.; (United States), Vol. 105:8
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
CARBON 13
NMR SPECTRA
ORGANIC OXYGEN COMPOUNDS
ANHYDRIDES
AROMATICS
COMPARATIVE EVALUATIONS
COMPUTER CALCULATIONS
CONFIGURATION INTERACTION
ESTERS
HYDROGEN
KETONES
OXALIC ACID ESTERS
SOLIDS
SPIN-LATTICE RELAXATION
TEREPHTHALIC ACID
THEORETICAL DATA
CARBON ISOTOPES
CARBOXYLIC ACID ESTERS
CARBOXYLIC ACIDS
DATA
DICARBOXYLIC ACIDS
ELEMENTS
EVEN-ODD NUCLEI
INFORMATION
ISOTOPES
LIGHT NUCLEI
NONMETALS
NUCLEI
NUMERICAL DATA
ORGANIC ACIDS
ORGANIC COMPOUNDS
RELAXATION
SPECTRA
STABLE ISOTOPES
400301* - Organic Chemistry- Chemical & Physicochemical Properties- (-1987)