CONICET | Buscador de Institutos y Recursos Humanos

Free energy relationships have been widely used in physical organic chemistry in the past 50 years to predict the reactivity of molecules in solution. Recently, it has been shown that, under certain conditions, this kind of analysis can be applied to molecular systems adsorbed on transition metal surfaces [1]. In the last 10 years, we have been interested in our group in the mechanochemical properties of thiols adsorbed on metallic surfaces such us Au or Cu [2]. We will present a significant amount of data that shows that the binding strength and the mechanical behavior of the thiol - gold bond can be predicted in terms of the electronic properties of the molecular systems and making use free energy relationships. On one side, we have focused on monothiols, which because of their simple molecular structure provide a straightforward way of tuning their electronic structure properties by means of changing a substituent in the molecule. On the other, we have also investigated multivalent thiolated molecules, since these are more interesting from the point of view of their potential applications, such as providing the anchoring for biocompatible polymers used to coat gold nanoparticles in medical applications [3]. Our results provide an interesting insight into how the nature of the thiol - gold bond can be tuned in order to obtain distinct mechanical stability of the system, and, more importantly, layout a methodology to predict their mechanochemical behavior from some simple empirical parameters and electronic structure descriptors that can be readily calculated. This provides one with a simple way to design a molecular structure for a given property. [1] R. A. van Santen et al. Chem. Rev. 2010, 110, 2005 - 2048. [2] J. Ribas-Arino, D. Marx Chem. Rev. 2012, 112, 5412-5487. [3] J. V. Jokerst et al. Nanomedicine 2011, 6, 715-728.