Hapticity-dependent charge transport through carbodithioate-terminated [5,15-bis(phenylethynyl)porphinato]zinc(II) complexes in metal-molecule-metal junctions.

Published

Journal Article

Single molecule break junction experiments and nonequilibrium Green's function calculations using density functional theory (NEGF-DFT) of carbodithioate- and thiol-terminated [5,15-bis(phenylethynyl)-10,20-diarylporphinato]zinc(II) complexes reveal the impact of the electrode-linker coordination mode on charge transport at the single-molecule level. Replacement of thiolate (-S(-)) by the carbodithioate (-CS2(-)) anchoring motif leads to an order of magnitude increase of single molecule conductance. In contrast to thiolate-terminated structures, metal-molecule-metal junctions that exploit the carbodithioate linker manifest three distinct conductance values. We hypothesize that the magnitudes of these conductances depend upon carbodithoate linker hapticity with measured conductances across Au-[5,15-bis(4'-(dithiocarboxylate)phenylethynyl)-10,20-diarylporphinato]zinc(II)-Au junctions the greatest when both anchoring groups attach to the metal surface in a bidentate fashion. We support this hypothesis with NEGF-DFT calculations, which consider the electron transport properties for specific binding geometries. These results provide new insights into the origin of molecule-to-molecule conductance heterogeneity in molecular charge transport measurements and the factors that optimize electrode-molecule-electrode electronic coupling and maximize the conductance for charge transport.

Full Text

Duke Authors

Cited Authors

  • Li, Z; Smeu, M; Park, T-H; Rawson, J; Xing, Y; Therien, MJ; Ratner, MA; Borguet, E

Published Date

  • October 2014

Published In

Volume / Issue

  • 14 / 10

Start / End Page

  • 5493 - 5499

PubMed ID

  • 25255444

Pubmed Central ID

  • 25255444

Electronic International Standard Serial Number (EISSN)

  • 1530-6992

International Standard Serial Number (ISSN)

  • 1530-6984

Digital Object Identifier (DOI)

  • 10.1021/nl502466a

Language

  • eng