title: 1D self-assembly of chemisorbed thymine on Cu(110) driven by dispersion forces.
abstract: Adsorption of thymine on a defined Cu(110) surface was studied using reflection-absorption infrared spectroscopy (RAIRS), temperature programmed desorption (TPD), and scanning tunnelling microscopy (STM). In addition, density functional theory (DFT) calculations were undertaken in order to further understand the energetics of adsorption and self-assembly. The combination of RAIRS, TPD, and DFT results indicates that an upright, three-point-bonded adsorption configuration is adopted by the deprotonated thymine at room temperature. DFT calculations show that the upright configuration adopted by individual molecules arises as a direct result of strong O-Cu and N-Cu bonds between the molecule and the surface. STM data reveal that this upright thymine motif self-assembles into 1D chains, which are surprisingly oriented along the open-packed [001] direction of the metal surface and orthogonal to the alignment of the functional groups that are normally implicated in H-bonding interactions. DFT modelling of this system reveals that the molecular organisation is actually driven by dispersion interactions, which cause a slight tilt of the molecule and provide the major driving force for assembly into dimers and 1D chains. The relative orientations and distances of neighbouring molecules are amenable for π-π stacking, suggesting that this is an important contributor in the self-assembly process.
authors.affiliation: Surface Science Research Centre and the Department of Chemistry, University of Liverpool, Liverpool L69 3BX, United Kingdom.
authors.forename: I
authors.initials: I
authors.lastname: Temprano
authors.affiliation: Surface Science Research Centre and the Department of Chemistry, University of Liverpool, Liverpool L69 3BX, United Kingdom.
authors.forename: G
authors.initials: G
authors.lastname: Thomas
authors.affiliation: Surface Science Research Centre and the Department of Chemistry, University of Liverpool, Liverpool L69 3BX, United Kingdom.
authors.forename: S
authors.initials: S
authors.lastname: Haq
authors.affiliation: Surface Science Research Centre and the Department of Chemistry, University of Liverpool, Liverpool L69 3BX, United Kingdom.
authors.forename: M S
authors.initials: MS
authors.lastname: Dyer
authors.affiliation: Surface Science Research Centre and the Department of Chemistry, University of Liverpool, Liverpool L69 3BX, United Kingdom.
authors.forename: E G
authors.initials: EG
authors.lastname: Latter
authors.affiliation: Surface Science Research Centre and the Department of Chemistry, University of Liverpool, Liverpool L69 3BX, United Kingdom.
authors.forename: G R
authors.initials: GR
authors.lastname: Darling
authors.affiliation: Chemical Physics, Department of Chemistry, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden.
authors.forename: P
authors.initials: P
authors.lastname: Uvdal
authors.affiliation: Surface Science Research Centre and the Department of Chemistry, University of Liverpool, Liverpool L69 3BX, United Kingdom.
authors.forename: R
authors.initials: R
authors.lastname: Raval
mesh_terms: D000327:Adsorption; D003300:Copper / Q000737:chemistry*; D015394:Molecular Structure; D011789:Quantum Theory; D013499:Surface Properties; D013941:Thymine / Q000737:chemistry*; D014732:Vibration
chemical_list: D003300:Copper; D013941:Thymine