Surface site distributions by solid-state multinuclear NMR spectroscopy. Pyridine binding to. gamma. -alumina by /sup 15/N and /sup 2/H NMR

Journal Article · Wed Mar 18 04:00:00 EST 1987 · J. Am. Chem. Soc.; (United States)

DOI:https://doi.org/10.1021/ja00240a008· OSTI ID:6869044

Majors, P D; Ellis, P D

The surface preparation dependent interactions of pyridine with ..gamma..-alumina are explored with solid-state /sup 15/N and /sup 2/H NMR spectroscopies. The observation of pyridine-/sup 15/N adsorbed to the surface reveals two resonances which are both characteristic of pyridine participating in a Lewis acid-base complex. These resonances display only partial tensorial averaging, and full information about the motionally averaged tensors is derived from magic angle spinning sideband simulations. Both resonances are assigned to complexes containing coordinatively unsaturated surface aluminum cations which occupy tetrahedral and octahedral sites in the defect spinel lattice. The relative distributions of tetrahedral and octahedral Lewis acid sites are determined as a function of surface preparation conditions, and the results are used with a simple surface preparation model to calculate the relative contribution of the various low index lattice planes to the composition of the surface. /sup 2/H NMR line-shape studies of pyridine-..cap alpha..,..cap alpha..'-d/sub 2/ on ..gamma..-alumina indicate a heterogeneous distribution of pyridine motional species, which reflect the physical and steric characteristics of the surface binding sites. Quadrupolar spin-echo line-shape simulations for various motional models indicate the significant contributions of pyridines undergoing continuous diffusion or twofold ring flips about their twofold symmetry axis.

• Research Organization: Univ. of South Carolina, Columbia
• OSTI ID: 6869044
• Journal Information: J. Am. Chem. Soc.; (United States), Journal Name: J. Am. Chem. Soc.; (United States) Vol. 109:6; ISSN JACSA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ADSORPTION
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
AZINES
CHALCOGENIDES
DATA
DEUTERIUM
DIFFUSION
EXPERIMENTAL DATA
HETEROCYCLIC COMPOUNDS
HYDROGEN COMPOUNDS
HYDROGEN ISOTOPES
INFORMATION
INORGANIC ACIDS
ISOTOPES
LABELLED COMPOUNDS
LEWIS ACIDS
LIGHT NUCLEI
MAGNETIC RESONANCE
NITROGEN 15
NITROGEN ISOTOPES
NMR SPECTRA
NUCLEAR MAGNETIC RESONANCE
NUCLEI
NUMERICAL DATA
ODD-EVEN NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PYRIDINE
PYRIDINES
RESONANCE
SOLIDS
SORPTION
SORPTIVE PROPERTIES
SPECTRA
STABLE ISOTOPES
SURFACE PROPERTIES
SURFACES