Structural and Electronic Properties of Strongly Correlated Molecular Systems

Abstract

This PhD. thesis reports on the study of two new types of strongly correlated molecular materials where the base molecular blocks are either fullerenes or phthalocyanines. Different experimental techniques like X-ray diffraction, Nuclear Magnetic Resonance, SQUID magnetometry, and muon spin relaxation (muSR) were employed. The experimental work was mainly focused on the structural investigation of the fullerenium salt C60(AsF6)2, a new type of fullerene based material where C60 is present in its oxidized form C602+, synthesized for the first time in our chemistry laboratory. We found that the C60 units, in C60(AsF6)2, polymerize through [2+2] cycloaddition and display a unusual zigzag arrangement which has never been observed, so far, in the fullerene polymers. Part of this work was also devoted to the investigation of the electronic properties of lithium phthalocyanines (LiPc, Li2Pc) and their lithium-intercalated phases, with the aim to shed more light on the possible analogy between these compounds and the fullerides, the well known charge transfer C60 salts where the electronic properties can be tuned by varying the stoichiometry of the intercalated alkali atoms. In particular a preliminary lithium intercalation has been performed on Li2Pc and the new lithium-doped phases Li2Li2Pc and Li3Li2Pc have been obtained.