Charge State Of Molecules Research Articles

Direct Observation of the Reduction of a Molecule on Nitrogen Pairs in Doped Graphene.

Incorporating functional atomic sites in graphene is essential for realizing advanced two-dimensional materials. Doping graphene with nitrogen offers the opportunity to tune its chemical activity with significant charge redistribution occurring between molecules and substrate. The necessary atomic scale understanding of how this depends on the spatial distribution of dopants, as well as their positions relative to the molecule, can be provided by scanning tunneling microscopy. Here we show that a noncovalently bonded molecule such as CoPc undergoes a variable charge transfer when placed on N-doped graphene; on a nitrogen pair, it undergoes a redox reaction with an integral charge transfer whereas a lower fractional charge transfer occurs over a single nitrogen. Thus, the charge state of molecules can be tuned by suitably tailoring the conformation of dopant atoms.

Generation, manipulation and characterization of molecules by atomic force microscopy

Using atomic manipulation, one can dissociate, form and rearrange bonds, as well as alter the conformation or charge state of molecules. The molecular structures of reactants, intermediates and products are revealed at unprecedented resolution by using atomic force microscopy (AFM) and a suitably functionalized tip. Our present capabilities of manipulation and imaging of molecules by AFM approach the level of control predicted by Richard P. Feynman in his famous lecture ‘There's plenty of room at the bottom’, in which he described how molecules and materials might be formed by attaching and detaching individual atoms at will. In this Review, we discuss recent progress and the future prospects of molecule generation by atom manipulation and molecular characterization by AFM. Atomic force microscopy (AFM) enables the imaging and manipulation of individual molecules at atomic resolution. This Review addresses experimental considerations, including operating modes and choices for tips and substrates. Examples are presented in which AFM is used to image molecules and induce bond formation or dissociation.