Molecular Conductors Based on M3Q7 Cluster Complexes

Molecular Conductors Based on M3Q7 Cluster Complexes 

Carrier generators in molecular conductors have been associated for a long time to a partial charge transfer between the HOMO (or LUMO) electronic band and other chemical species. These systems are known as two-component molecular conductors. Tetrathiofulvalene derivatives are versatile systems for the formation of molecular organic conductors due to their electron donor capacity by transferring one u-electron from the HOMO orbital, and to their planar shape that promotes their stacking as a consequence of the n-n orbital overlap. The electronic properties of these salts are essentially determined by the packing pattern of the donor molecules which, in turn, depends on the counter-ion. 

At the turn of this century it was realized that carrier generation was also possible between the HOMO and LUMO band even in neutral single-component materials assuming that there was a small HOMO-LUMO gap and conduction paths have been associated with the presence of large transverse intermolecular interactions. The most relevant examples of single-component molecular conductors are the mononuclear M(dithiolate)2 (M = Co, Ni, Cu, Au) complexes with 

The room temperature electrical conductivity of single crystals of M03S7 (dmit)3 along the c axis is 25 S cm, which is very high for a neutral molecular crystal. The variation of the magnetic susceptility (/) with the temperature does not follow a Curie-Weis law with a continuous decrease of /T vs. Tupon cooling 

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