title: On-surface coordination chemistry: direct imaging of the conformational freedom of an axial ligand at room temperature.
abstract: The on-surface ligation of nitric oxide (NO) with Co-tetraphenylporphyrin (CoTPP) sublimed onto oxygen-reconstructed Ni(001) is studied using room-temperature scanning tunneling microscopy (STM) and complementary photoemission spectroscopies. On the oxygen-reconstructed substrates, the porphyrins are observed to form well-ordered, self-assembled layers. STM directly images the NO ligand as a characteristic feature in the center of the molecule. Under certain STM imaging conditions the dynamicity of this feature can be related to the temperature-activated conformational flexibility of the NO ligand. This provides an indirect confirmation of the bending of the Co-NO bond, as predicted from classical coordination chemistry.
authors.affiliation: Laboratory for Micro- and Nanotechnology, Paul Scherrer Institute, 5232 Villigen-PSI, Switzerland. thomas.jung@psi.ch.
authors.forename: Christian
authors.initials: C
authors.lastname: Wäckerlin
authors.forename: Dorota
authors.initials: D
authors.lastname: Siewert
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Jung
authors.forename: Nirmalya
authors.initials: N
authors.lastname: Ballav