STM Study of Gold(I) Pyrazolates: Distinct Morphologies,
Layer Evolution, and Cooperative Dynamics
- Publication date
- Publisher
Abstract
We describe the first study of trinuclear
gold(I) pyrazolates on
the molecular level by time-dependent scanning tunneling microscopy
(STM). On the graphite/1-octanoic acid interface dodecyl-functionalized
gold pyrazolates formed concentration-controlled morphologies. We
found two types of monomeric packing and one dimeric type with two
trinuclear gold pyrazolates next to each other on the surface. For
an octadecyl-functionalized derivative all studied concentrations
resulted in a dimeric morphology. However, different concentrations
led to different transient states during the layer evolution. At low
concentrations, a transient monomeric state was present with the alkyl
chains in a gauche-conformation that subsequently converted to a more
optimized anti-conformation. At higher concentrations a less stable
“line” polymorph was observed. The confinement of the
molecules to the surface led to cooperative dynamics, in which two
molecules in a dimer moved as if they were one particle. Furthermore,
in a higher level of cooperativity, the rotation of one dimer appears
to induce rotations in coupled neighboring dimers