Hydration layers play a key role in many technical and biological systems, but our understanding of these structures remains very limited. Here, we investigate the molecular processes driving hydration of a chiral metal-organic surface, bitartrate on Cu(110), which consists of hydrogen-bonded bitartrate rows separated by exposed Cu. Initially water decorates the metal channels, hydrogen bonding to the exposed O ligands that bind bitartrate to Cu, but does not wet the bitartrate rows. At higher temperature, water inserts into the structure, breaks the existing intermolecular hydrogen bonds, and changes the adsorption site and footprint. Calculations show this process is driven by the creation of stable adsorption sites between the carboxylate ligands, to allow hydration of O-Cu ligands within the interior of the structure. This work suggests that hydration of polar metal-adsorbate ligands will be a dominant factor in many systems during surface hydration or self-assembly from solution.
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http://dx.doi.org/10.1021/jacs.0c04747 | DOI Listing |
J Am Chem Soc
August 2020
Surface Science Research Centre and Department of Chemistry, University of Liverpool, Liverpool L69 3BX, United Kingdom.
Hydration layers play a key role in many technical and biological systems, but our understanding of these structures remains very limited. Here, we investigate the molecular processes driving hydration of a chiral metal-organic surface, bitartrate on Cu(110), which consists of hydrogen-bonded bitartrate rows separated by exposed Cu. Initially water decorates the metal channels, hydrogen bonding to the exposed O ligands that bind bitartrate to Cu, but does not wet the bitartrate rows.
View Article and Find Full Text PDFPhys Chem Chem Phys
March 2017
Surface Science Research Centre and Department of Chemistry, University of Liverpool, Liverpool L69 3BX, UK.
Local or global ordering of chiral molecules at a surface is a key step in both chiral separation and heterogeneous enantioselective catalysis. Using density functional theory and scanning probe microscopy results, we find that the accepted structural model for the well known bitartrate on Cu(110) chiral system cannot account for the chiral segregation observed. Instead, we show that this strongly bound, chiral adsorbate changes its adsorption footprint in response to the local environment.
View Article and Find Full Text PDFJ Chem Phys
October 2009
Department of Physical Chemistry, China Pharmaceutical University, Nanjing 210009, People's Republic of China.
Periodic density functional theory calculations are used to systematically investigate, for the first time, the mechanisms for chemical transformations of (R,R)-tartaric acid on a model Cu(110) surface. The overall potential energy surface for the chemical transformations is revealed. The calculations show that the adsorption of the intact biacid molecules of (R,R)-tartaric acid on Cu(110) surface is not strong, but upon adsorption on Cu(110), the biacid molecules will chemically transform immediately, rather than desorb from the surface.
View Article and Find Full Text PDFChemistry
July 2005
Nanoscale Materials Science, Swiss Federal Institute for Materials Science and Technology (EMPA), Dübendorf, Switzerland.
Two-dimensional lattice structures formed by racemic tartaric acid on a single crystalline Cu(110) surface have been studied and compared with the enantiopure lattices. At low coverage, the doubly deprotonated bitartrate species is separated into two-dimensional conglomerates showing opposite enantiomorphism. At higher coverage, however, a singly deprotonated monotartrate species forms a heterochiral, racemic crystal lattice.
View Article and Find Full Text PDFJ Am Chem Soc
August 2004
Swiss Federal Laboratories for Materials Research (EMPA), Molecular Surfaces Technologies-125, Uberlandstrasse 129, CH-8600 Dübendorf, Switzerland.
The vast majority of chiral compounds crystallize into racemic crystals. It has been predicted and was experimentally established as a rule that chiral molecules on surfaces are more easily separated into homochiral domains due to confinement into a plane and lower entropic contributions. We investigated the formation and stability of two-dimensional tartrate crystals on a Cu(110) surface for the racemic mixture for the first time by means of temperature-programmed desorption (TPD), low-energy electron diffraction (LEED), and X-ray photoelectron spectroscopy (XPS).
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