Extended metal atom chains

[1] An EMAC molecule contains a linear string of transition metals (typically Cr, Co, Ni, or Cu) that are bonded to each other and surrounded helically by organic ligands.

The organic ligands template the formation of the chains by bringing the metal ions together and aligning them into a linear string.

While this debate led to the realization that the compound can be used as a molecular switch, it also created a new problem since none of the recognized types of isomerism could explain the existence of a molecule in two structural forms that differ only in the length of one or more bonds (and not in their stereochemistry or connectivity of the atoms).

The problem was finally resolved through a quantum chemical study by Pantazis and McGrady, who showed that the two structural forms result from different electronic configurations.

Moreover, conductance can be controlled and fine-tuned by oxidation or reduction of the metal chain, opening the way for the construction of molecular rheostats, switches, and transistors.