title: Detection of different oxidation states of individual manganese porphyrins during their reaction with oxygen at a solid/liquid interface.
abstract: Manganese porphyrins have been extensively investigated as model systems for the natural enzyme cytochrome P450 and as synthetic oxidation catalysts. Here, we report single-molecule studies of the multistep reaction of manganese porphyrins with molecular oxygen at a solid/liquid interface, using a scanning tunnelling microscope (STM) under environmental control. The high lateral resolution of the STM, in combination with its sensitivity to subtle differences in the electronic properties of molecules, allowed the detection of at least four distinct reaction species. Real-space and real-time imaging of reaction dynamics enabled the observation of active sites, immobile on the experimental timescale. Conversions between the different species could be tuned by the composition of the atmosphere (argon, air or oxygen) and the surface bias voltage. By means of extensive comparison of the results to those obtained by analogous solution-based chemistry, we assigned the observed species to the starting compound, reaction intermediates and products.
authors.affiliation: Radboud University Nijmegen, Institute for Molecules and Materials, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands.
authors.forename: Duncan
authors.initials: D
authors.lastname: den Boer
authors.forename: Min
authors.initials: M
authors.lastname: Li
authors.forename: Thomas
authors.initials: T
authors.lastname: Habets
authors.forename: Patrizia
authors.initials: P
authors.lastname: Iavicoli
authors.forename: Alan E
authors.initials: AE
authors.lastname: Rowan
authors.forename: Roeland J M
authors.initials: RJ
authors.lastname: Nolte
authors.forename: Sylvia
authors.initials: S
authors.lastname: Speller
authors.forename: David B
authors.initials: DB
authors.lastname: Amabilino
authors.forename: Steven
authors.initials: S
authors.lastname: De Feyter
authors.forename: Johannes A A W
authors.initials: JA
authors.lastname: Elemans
mesh_terms: D008345:Manganese / Q000737:chemistry*; D016252:Microscopy, Scanning Tunneling; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry*; D011166:Porphyrins / Q000737:chemistry*
chemical_list: D011166:Porphyrins; D008345:Manganese; D010100:Oxygen