Molecular Dynamics of Pyridine Adsorbed on the Silica Surface

Autor:	Gary E. Maciel, Joseph A. DiVerdi, Takeshi Kobayashi
Rok vydání:	2007
Předmět:	Deuterium NMR Stereochemistry Silica gel Ring (chemistry) Surfaces Coatings and Films Electronic Optical and Magnetic Materials Crystallography chemistry.chemical_compound Molecular dynamics General Energy chemistry Pyridine Monolayer Molecule Physical and Theoretical Chemistry Spectroscopy
Zdroj:	The Journal of Physical Chemistry C. 111:5982-5989
ISSN:	1932-7455 1932-7447
Popis:	The molecular dynamics of pyridine adsorbed onto dry high-surface-area silica gel was studied using solid-state deuterium NMR spectroscopy. Selectively and totally deuterated pyridine samples were used to identify the spectral signatures associated with each ring location and to identify the dynamical modes present in the surface adsorbed species. Loading levels corresponding to 0.8 and 0.2 monolayer coverage were studied. At 174 K and 0.8 monolayer, the adsorbed pyridine molecules are found in three motional modes: a fraction is found to be static, a larger fraction is found executing fast discontinuous rotation (180° ring flips) about the pyridine Cγ−N axis, and a very small fraction is found in fast continuous rotation (diffusion) about the pyridine Cγ−N axis, all referred to a 5 × 10-6 s time scale. No evidence of O−H−N rotation about the Si−O bond (“swinging arm” motion) is observed. The pyridine flips and rotations permit measurement of the angle between the Cγ−N axis and each of the Cα−D and Cβ−D ...
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::8d186e7165b0dc6170febe1bf1cd4621 https://doi.org/10.1021/jp067353q Zobrazit plný text záznamu