Crystalline structures of alkylamide monolayers adsorbed on the surface of graphite.
Synchrotron X-ray and neutron diffraction have been used to determine the two-dimensional crystalline structures of alkylamides adsorbed on graphite at submonolayer coverage. The calculated structures show that the plane of the carbon backbone of the amide molecules is parallel to the graphite substrate. The molecules form hydrogen-bonded dimers, and adjacent dimers form additional hydrogen bonds yielding extended chains. By presenting data from a number of members of the homologous series, we have identified that these chains pack in different arrangements depending on the number of carbons in the amide molecule. The amide monolayers are found to be very stable relative to other closely related alkyl species, a feature which is attributed to the extensive hydrogen bonding present in these systems. The characteristics of the hydrogen bonds have been determined and are found to be in close agreement with those present in the bulk materials.
Bhinde
Tej
T
BP Institute and Department of Chemistry, University of Cambridge, Madingley Road, Cambridge CB3 0EZ, United Kingdom.
Clarke
Stuart M
SM
Phillips
Tamsin K
TK
Arnold
Thomas
T
Parker
Julia E
JE