10.1021/acsnano.5b03466.s001 Howon Kim Howon Kim Yun Hee Chang Yun Hee Chang Won-Jun Jang Won-Jun Jang Eui-Sup Lee Eui-Sup Lee Yong-Hyun Kim Yong-Hyun Kim Se-Jong Kahng Se-Jong Kahng Probing Single-Molecule Dissociations from a Bimolecular Complex NO–Co-Porphyrin American Chemical Society 2015 theory calculations energy pulses dissociation rate blood pressure control tunneling junctions dissociation mechanisms threshold voltages 0.1 nA tunneling Bimolecular Complex molecule dissociation experiments power law relations probe reaction mechanisms molecule level scanning tunneling microscope stochastically tunneling electrons 2015-07-28 00:00:00 Journal contribution https://acs.figshare.com/articles/journal_contribution/Probing_Single_Molecule_Dissociations_from_a_Bimolecular_Complex_NO_Co_Porphyrin/2146588 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.