Self-assembled aggregates formed by single-molecule magnets on a gold surface

Abstract

The spontaneous ordering of molecules into two-dimensional self-assembled arrays is commonly stabilized by directional intermolecular interactions that may be promoted by the addition of specific chemical side groups to a molecule. In this paper, we show that self-assembly may also be driven by anisotropic interactions that arise from the three-dimensional shape of a complex molecule. We study the molecule Mn12 O12 (O2 CCH 3)16 (H2O)4 (Mn12 (acetate)16), which is transferred from solution onto a Au(111) substrate held in ultrahigh vacuum using electrospray deposition (UHV-ESD). The deposited Mn12 (acetate)16 molecules form filamentary aggregates because of the anisotropic nature of the molecule-molecule and molecule-substrate interactions, as confirmed by molecular dynamics calculations. The fragile Mn12O12 core of the Mn 12 (acetate)16 molecule is compatible with the UHV-ESD process, which we demonstrate using near-edge X-ray adsorption fine-structure spectroscopy. UHV-ESD of Mn12 (acetate)16 onto a surface that has been prepatterned with a hydrogen-bonded supramolecular network provides additional control of lateral organization. © 2010 Macmillan Publishers Limited. All rights reserved.