Probing Single-Molecule Dissociations from a Bimolecular Complex NO-Co-Porphyrin

Howon Kim, Yun Hee Chang, Won Jun Jang, Eui Sup Lee, Yong Hyun Kim, Se Jong Kahng

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)


Axial coordinations of diatomic NO molecules to metalloporphyrins play key roles in dynamic processes of biological functions such as blood pressure control and immune response. Probing such reactions at the single molecule level is essential to understand their physical mechanisms but has been rarely performed. Here we report on our single molecule dissociation experiments of diatomic NO from NO-Co-porphyrin complexes describing its dissociation mechanisms. Under tunneling junctions of scanning tunneling microscope, both positive and negative energy pulses gave rise to dissociations of NO with threshold voltages, +0.68 and -0.74 V at 0.1 nA tunneling current on Au(111). From the observed power law relations between dissociation rate and tunneling current, we argue that the dissociations were inelastically induced with molecular orbital resonances by stochastically tunneling electrons, which is supported with our density functional theory calculations. Our study shows that single molecule dissociation experiments can be used to probe reaction mechanisms in a variety of axial coordinations between small molecules and metalloporphyrins.

Original languageEnglish
Pages (from-to)7722-7728
Number of pages7
JournalACS nano
Issue number7
Publication statusPublished - 2015 Jul 28

Bibliographical note

Publisher Copyright:
© 2015 American Chemical Society.


  • bimolecular reaction
  • density functional theory
  • dissociation
  • metalloporphyrin
  • nitric oxide
  • scanning tunneling microscopy

ASJC Scopus subject areas

  • General Materials Science
  • General Engineering
  • General Physics and Astronomy


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