Self-assembled monolayer of Cr7Ni molecular nanomagnets by sublimation

We show, by complementary spectroscopic and STM analysis, that Cr 7Ni derivatives are suitable to be sublimed in UHV conditions. Cr7Ni-bu weakly bonds to gold surface and can diffuse relatively freely on it, forming monolayers with hexagonal 2D packing. Conversely, by adding a functional thiol group to the central dibutylamine, a covalent bond between the molecule and surface gold adatoms is promoted, leading to a strong molecular grafting and the formation of a disordered monolayer. These two examples demonstrate the possibility to control the assembly of a large molecular complex, as rationalized by DFT calculations that establish different energy scales in the deposition processes. Moreover, low-temperature XMCD sprectra show that the magnetic features of Cr7Ni rings deposited in UHV on gold remain unchanged with respect to those of the corresponding bulk sample. © 2011 American Chemical Society.