Abstract
Owing to their high saturation magnetisation, cobalt nanoparticles hold significant potential for the hyperthermia treatment of tumours. Covalent binding of carboxylic acids to the nanoparticles can induce biocompatibility, whilst also preventing the formation of surface oxides which reduce the magnetic properties of cobalt. Understanding the origin of the acid-metal interaction is key, yet probably the most experimentally challenging step, for the rational design of such entities. In this density functional theory study, we use static calculations to establish that a 57-atom Co cluster is the smallest model able to reproduce the adsorption behaviour of carboxylic acids, and ab initio metadynamics to obtain the structure and the free energy landscape for its interaction with valeric acid. Our simulations show that a bridging bidentate binding mode has a stronger affinity compared to monodentate binding, with energetically high transition barriers between the two. A chelate interaction mode of two carboxyl oxygen atoms can be formed as an intermediate. These results clarify the organic-inorganic interactions in the cobalt-acid system, providing a basis for the rational design of biocompatible metallic nanoparticles.
| Original language | English |
|---|---|
| Pages (from-to) | 985-996 |
| Number of pages | 12 |
| Journal | Physical Chemistry Chemical Physics |
| Volume | 22 |
| Issue number | 3 |
| DOIs | |
| Publication status | Published - 2020 |
Funding
BF is grateful to Cardiff University for support through a Research Scholarship from the School of Chemistry. We acknowledge the Engineering and Physical Sciences Research Council (Grant no. EP/R512503/1 and EP/K009567/2) for funding. This work was performed using the computational facilities of the Advanced Research Computing @ Cardiff_(ARCCA) Division, Cardiff University. Via our membership of the UK’s HPC Materials Chemistry Consortium, which is funded by EPSRC (EP/L000202), this work made use of the facilities of ARCHER, the UK’s national high-performance computing service, which is funded by the Office of Science and Technology through EPSRC’s High End Computing Programme. Information on the data underpinning the presented results, including how to access them, can be found in the Cardiff University data catalogue at http://doi.org/10.17035/ d.2019.0081261776.