title: Probing pi-coupling in molecular junctions.
abstract: Charge transport characteristics for metal-molecule-metal junctions containing two structurally related pi-conjugated systems were studied to probe pi-pi interactions in molecular junctions. The first molecule contains a typical pi-conjugated framework derived from phenylene vinylene units, whereas the second has the phenylene vinylene structure interrupted by a [2.2]paracyclophane (pCp) core. Electrochemical investigations were used to characterize the defects and packing density of self-assembled monolayers of the two molecules on gold surfaces and to enable quantitative comparison of their transport characteristics. Current-voltage measurements across molecular junctions containing the two species demonstrate that the pCp moiety yields a highly conductive break in through-bond pi-conjugation. The observed high conductivity is consistent with density functional theory calculations, which demonstrate strong through-space pi-pi coupling across the pCp moiety.
authors.affiliation: Department of Chemistry, Institute for Polymers and Organic Solids, University of California, Santa Barbara, CA 93106, USA.
authors.forename: Dwight S
authors.initials: DS
authors.lastname: Seferos
authors.forename: Scott A
authors.initials: SA
authors.lastname: Trammell
authors.forename: Guillermo C
authors.initials: GC
authors.lastname: Bazan
authors.forename: James G
authors.initials: JG
authors.lastname: Kushmerick
mesh_terms: D004563:Electrochemistry / Q000295:instrumentation / Q000379:methods*; D008280:Magnetics; D008958:Models, Molecular; D008968:Molecular Conformation; D036103:Nanotechnology; D010880:Piperidines / Q000737:chemistry*; D055672:Static Electricity; D013343:Styrenes / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D010880:Piperidines; D013343:Styrenes