Deposition of Functionalized Cr7Ni “Molecular Rings on Graphite from the Liquid Phase

Graphite is a clean substrate and its nanostructures hold great potentialities for applications.Anchoring large molecules on graphite represents a challenge for several reasons thatessentially rise from the planar bonds of the packed honeycomb structure of carbon. Here wereport a systematic investigation by AFM and XPS on different derivatives of molecularCr7Ni rings deposited on highly oriented pyrolytic graphite (HOPG). Cr7Ni is emerging as aprototipical example of molecular antiferromagnet on which quantum phenomena andcoherence have been demonstrated. For the deposition of Cr7Ni on HOPG, we essentiallyadopt two strategies: in the first instance, Cr7Ni rings have been functionalized with extendedalkyl/benzene terminations while, in the second case, we firstly deposit a self-assembledmonolayer of alkyl chains with sulfonate terminations and then we use a cationic Cr7Niderivative. In both cases the electronic bond with the carbon surface is soft but the two-stepprocedure results efficient, albeit indirect, in sticking molecular Cr7Ni on HOPG. Thesestrategies can be easily extended to deposit other complex molecular aggregates on graphiteby liquid phase.