STRUCTURAL AND ELECTRONIC-PROPERTIES OF A NEW TWO-DIMENSIONAL MOLECULAR-METAL, ET2ME2N[NI(DMIT)2]2

Structural and electronic properties of the anion radical salts M[Ni(dmit)2]2(dmit= 4,5-dimercapto-1,3-dithiole-2-thione; M=Et2Me2N, EtMe3N, Me4P, Me4As, Me4Sb, Me3S(O), Me3S) have been investigated. Among them, α-Et2Me2N[Ni(dmit)2]2 retains metallic behavior down to 1.5 K. In the crystal of α-Et2Me2N[Ni(dmit)2]2, planar Ni(dmit)2 units are stacked in such a way that one molecule overlaps with two molecules. Such a spanning overlap mode has provided a two-dimensional electronic structure. This compound is the first two-dimensional metal derived from the π-acceptor molecule.