Studies of lability and inertia on the surface of plasmonic nanoparticles aiming the development of systems for molecular recognition and transfer of information

Abstract

All nanoscience related studies are of fundamental importance, not only because the several ways of applying nanomaterials resulting from different kinds of research, but also because it is absolutely necessary to acquire a deeper knowledge of surface chemistry to be able to describe functional interfaces. The idea of the first part of the project is to study metal-ligand bonds from the point of view of plasmonic nanoparticles to verify classic concepts like lability / inertia and the hard / soft character of these ligands when coordinated to nanoparticles. The ligand exchange studies will be accomplished by mass spectrometry and SERS and these analyzes will be performed with gold nanoparticles immobilized in a film of oxide nanoparticles previously synthesized, to check if there is any influence in ligand exchange, dependent on the nature of the oxides employed. As for the ligands, the molecules 2,4,6-trimercapto-1,3,5-triazine and 2,4,6-triamine-1,3,5-trazina will be studied, because they both have several coordination sites, depending on concentration and pH, which will enable a greater understanding on the thermodynamic and kinetics of metal-ligand bond formations on the surface. Having all these experiments optimized, the second part of the project is to use all the knowledge acquired previously to synthesize wire-like plasmonic nanoparticles and immobilize them on the same oxide films previously used, to evaluate the influence of the substrate in the propagation of molecular information. Finally, the project is meant to answer fundamental questions about molecular processes on surface, describing metal-ligand interfaces by classical concepts of coordination chemistry. Thus, one can evaluate the ligand exchange going beyond the conventional chemical bond using nanoparticles, by changing size, shape, interaction with light and substrates, which can directly affect the development of sensors and devices for molecular recognition and transfer of information. (AU)