TY - JOUR
T1 - Adsorption-induced chirality in highly symmetric hydrocarbon molecules
T2 - lattice matching to substrates of lower symmetry
AU - Richardson, Neville V.
PY - 2007/10/31
Y1 - 2007/10/31
N2 - For molecules of high symmetry and lateral interactions dominated by van der Waals' interactions, such as some planar aromatic hydrocarbons, there is a preference for hexagonal close packing on adsorption. Optimization of packing by minimization of the interadsorbate spacing may favour correlated rotations of the molecules, which reduces the symmetry and leads to chiral properties in the two-dimensional overlayer. Independently, mapping of the preferred hexagonal packing on to lower symmetry substrates, which provide pseudo-hexagonal lattices, can lead to alternative mirror image lattices. The interaction of these independent chiral phenomena gives rise to diastereoisomerism in the adsorbed array. Coronene and its substituted, larger derivative hexa-tert-butyl hexabenzocoronene adsorbed on copper surfaces provide examples of these phenomena. A new structure is proposed for coronene on Cu{100} while new STM and LEED data are presented for this molecule adsorbed on Cu{110}. Finally, the adsorption of hexa-tertbutyl hexabenzocoronene on Cu{110} is re-examined and the implications of the competition between two, closely related, pseudo-hexagonal lattices are considered.
AB - For molecules of high symmetry and lateral interactions dominated by van der Waals' interactions, such as some planar aromatic hydrocarbons, there is a preference for hexagonal close packing on adsorption. Optimization of packing by minimization of the interadsorbate spacing may favour correlated rotations of the molecules, which reduces the symmetry and leads to chiral properties in the two-dimensional overlayer. Independently, mapping of the preferred hexagonal packing on to lower symmetry substrates, which provide pseudo-hexagonal lattices, can lead to alternative mirror image lattices. The interaction of these independent chiral phenomena gives rise to diastereoisomerism in the adsorbed array. Coronene and its substituted, larger derivative hexa-tert-butyl hexabenzocoronene adsorbed on copper surfaces provide examples of these phenomena. A new structure is proposed for coronene on Cu{100} while new STM and LEED data are presented for this molecule adsorbed on Cu{110}. Finally, the adsorption of hexa-tertbutyl hexabenzocoronene on Cu{110} is re-examined and the implications of the competition between two, closely related, pseudo-hexagonal lattices are considered.
KW - SCANNING-TUNNELING-MICROSCOPY
KW - LAYERED SEMICONDUCTORS
KW - CORONENE
KW - SURFACES
KW - GROWTH
KW - ELECTRONICS
KW - FILMS
KW - LEED
KW - STM
UR - http://www.scopus.com/inward/record.url?scp=35748953136&partnerID=8YFLogxK
U2 - 10.1088/1367-2630/9/10/395
DO - 10.1088/1367-2630/9/10/395
M3 - Article
SN - 1367-2630
VL - 9
JO - New Journal of Physics
JF - New Journal of Physics
M1 - 395
ER -