Molecular design and development of single-component molecular metal

The requirements for designing single-component molecular metals were derived from the results of crystal structure analyses, resistivity measurements, band structure calculations, performed on molecular conductors with extended TTF-ligands [Ni(ptdt)2] (ptdt: propylene dithiotetrathiafulvalenedithiolate). The development of π molecule with a small HOMO–LUMO gap and TTF-like skelton is a key step to obtain single-component molecular metal. We have prepared the crystals of [Ni(tmdt)2] (tmdt: trimethylenetetrathiafulvalenedithiolate) and examined the crystal structure and resistivity. This single-component molecular crystal was found to be the first three-dimensional synthetic metal composed of planar molecules with metallic nature down to 0.6 K.