Chemical, Spectral, Structural, and Charge Transport Properties of the 'Molecular Metals' Produced by Iodination of Nickel Phthalocyanine

摘要

Partial oxidation of metallophthalocyanines with iodine has provided an extensive new class of molecular conductors. As illustrated in the present case with nickel phthalocyanine, the properties of the resulting solid state array of pi-cation radicals include electrical conductivity which is comparable with that of the best-known stacked molecular conductors. A particularly intriguing feature of NiPcI1.0 charge transport is a transition from metallic to semi-conducting behavior which apparently is not reflected in the magnetic properties of the carriers. It is tempting to speculate that this behavior reflects a change in carrier mobility brought about by some subtle structural rearrangement such as a change in the ordering of the triiodide chains. In a broader perspective, the iodinated metallophthalocyanines, such as those reported here, represent the first entry into a widening area of conductive materials based upon the ligand pi systems of mixed-valent metallo-macrocyclic arrays. Clearly the insights gleaned and the methodology developed will lead to an ever-deepening understanding of those molecular characteristics which facilitate charge conduction and which optimize materials performance.