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Title: Reactivity of pyridine on Mo(110): C-H and C-N bond activation

Abstract

Pyridine undergoes competing desorption (30 {plus minus} 10%) and decomposition to surface carbon, nitrogen, and gaseous dihydrogen on Mo(110). Pyridine is shown to molecularly desorb, since no reversible C-H bond activation occurs in isotopic exchange experiments. The temperature at which total decomposition involving the cleavage of C-H, C-C, and C-N bonds occurs was found to increase with increasing coverage of pyridine and related surface fragments. Some C-H bond breaking occurs at temperatures less than 325 K as evidenced by isotopic labeling results. X-ray photoelectron spectroscopy results show that C-C bond activation occurs below 500 K. Notably, at least one of the C-N bonds in pyridine is intact at temperatures up to 500 K at high coverages on the basis of X-ray photoelectron spectroscopy results. An isotope effect in dihydrogen formation was observed in the reaction of a mixture of C{sub 5}D{sub 5}N and C{sub 5}H{sub 5}N. At high coverage and low temperature there is more than one species on the surface, one of which is assigned as molecular pyridine bound through nitrogen. The presence of surface hydrogen increases the amount of molecular desorption and, therefore, decreases the total amount of irreversible decomposition by {approx} 40%. As a result of themore » lower coverage of species on the surface after molecular desorption, total decomposition, and in particular C-N bond cleavage, occurs at lower temperature than on the initially clean surface.« less

Authors:
;  [1]
  1. (Harvard Univ., Cambridge, MA (USA))
Publication Date:
OSTI Identifier:
5045220
DOE Contract Number:  
FG02-84ER13289
Resource Type:
Journal Article
Journal Name:
Journal of Physical Chemistry; (USA)
Additional Journal Information:
Journal Volume: 93:5; Journal ID: ISSN 0022-3654
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; DEUTERIUM COMPOUNDS; DECOMPOSITION; DESORPTION; MOLYBDENUM; CATALYTIC EFFECTS; PYRIDINES; ACTIVATION ENERGY; BINDING ENERGY; CATALYSIS; CATALYSTS; CHEMICAL BONDS; EXPERIMENTAL DATA; HIGH TEMPERATURE; ISOTOPE EFFECTS; MEDIUM TEMPERATURE; PHOTOELECTRON SPECTROSCOPY; X RADIATION; AZINES; CHEMICAL REACTIONS; DATA; ELECTROMAGNETIC RADIATION; ELECTRON SPECTROSCOPY; ELEMENTS; ENERGY; HETEROCYCLIC COMPOUNDS; HYDROGEN COMPOUNDS; INFORMATION; IONIZING RADIATIONS; METALS; NUMERICAL DATA; ORGANIC COMPOUNDS; ORGANIC NITROGEN COMPOUNDS; RADIATIONS; SPECTROSCOPY; TRANSITION ELEMENTS; 400201* - Chemical & Physicochemical Properties

Citation Formats

Serafin, J.G., and Friend, C.M. Reactivity of pyridine on Mo(110): C-H and C-N bond activation. United States: N. p., 1989. Web. doi:10.1021/j100342a058.
Serafin, J.G., & Friend, C.M. Reactivity of pyridine on Mo(110): C-H and C-N bond activation. United States. doi:10.1021/j100342a058.
Serafin, J.G., and Friend, C.M. Thu . "Reactivity of pyridine on Mo(110): C-H and C-N bond activation". United States. doi:10.1021/j100342a058.
@article{osti_5045220,
title = {Reactivity of pyridine on Mo(110): C-H and C-N bond activation},
author = {Serafin, J.G. and Friend, C.M.},
abstractNote = {Pyridine undergoes competing desorption (30 {plus minus} 10%) and decomposition to surface carbon, nitrogen, and gaseous dihydrogen on Mo(110). Pyridine is shown to molecularly desorb, since no reversible C-H bond activation occurs in isotopic exchange experiments. The temperature at which total decomposition involving the cleavage of C-H, C-C, and C-N bonds occurs was found to increase with increasing coverage of pyridine and related surface fragments. Some C-H bond breaking occurs at temperatures less than 325 K as evidenced by isotopic labeling results. X-ray photoelectron spectroscopy results show that C-C bond activation occurs below 500 K. Notably, at least one of the C-N bonds in pyridine is intact at temperatures up to 500 K at high coverages on the basis of X-ray photoelectron spectroscopy results. An isotope effect in dihydrogen formation was observed in the reaction of a mixture of C{sub 5}D{sub 5}N and C{sub 5}H{sub 5}N. At high coverage and low temperature there is more than one species on the surface, one of which is assigned as molecular pyridine bound through nitrogen. The presence of surface hydrogen increases the amount of molecular desorption and, therefore, decreases the total amount of irreversible decomposition by {approx} 40%. As a result of the lower coverage of species on the surface after molecular desorption, total decomposition, and in particular C-N bond cleavage, occurs at lower temperature than on the initially clean surface.},
doi = {10.1021/j100342a058},
journal = {Journal of Physical Chemistry; (USA)},
issn = {0022-3654},
number = ,
volume = 93:5,
place = {United States},
year = {1989},
month = {3}
}