Design of molecular magnets with graphene fragments

Identifier:  TFG:1705

Handle: https://hdl.handle.net/20.500.11797/TFG1705

Authors:  López Calero, Adrián

Abstract:
In this project, the possibility of creating ferromagnetic organic molecules from phenalenyl as graphene fragment is explored. For doing this, wide variety of molecules have been studied, creating dimers and oligomers that are bonded through different bridges, based on phenalenyl as building blocks. Magnetic coupling has been calculated using density functional theory and broken symmetry approach (to optimize the time spent on calculations, comparison between some functional and basis have been carried out). From data obtained, different trends are established to find which variables are the most relevant in the design of the molecules that raises the ferromagnetic character the most. The possibility of a graphene net with vacants exhibiting ferromagnetic character have also been analyzed, but it has been found that DFT with broken symmetry approach is not enough consistent method to calculate magnetic coupling for this type of systems, because it introduces a considerable spin contamination in the results. Multiconfigurational methods could be more appropriate because they consider the multiconfigurational character of this systems. It is necessary to comment that in this project, neither the synthesis nor the stability of these molecules at room temperature, have been studied but this could be the next step.