Inorganic Chemistry, Vol.36, No.23, 5262-5269, 1997
Enhancement of the dimensionality of molecular pi conductors by the selone substitution of M(dmit)(2) (M = Ni, Pd) systems: Newly synthesized dmise compounds [MexH4-xN][Ni(dmise)(2)](2) (x = 1-3) and Cs[Pd(dmise)(2)](2) (dmise = 4,5-dimercapto-1,3-dithiole-2-selone)
Single crystals of [Me3HN][Ni(dmise)(2)](2), [Me2H2N][Ni(dmise)(2)](2), [MeH3N][Ni(dmise)(2)](2), and Cs[Pd(dmise)(2)](2) were grown electrochemically. The crystal structures of [Me3HN][Ni(dmise)(2)](2), [Me2H2][Ni(dmise)(2)](2) and [MeH3N][Ni(dmise)(2)](2) were determined. Crystal data are as follows: [Me3HN][Ni(dmise)(2)](2) (C15H10NNi2S16Se4), triclinic, P (1) over bar, a=7.606(3)Angstrom, b=17.761(3)Angstrom, c=6.660(2)Angstrom, alpha=100.27(2)degrees, beta=114.93(2)degrees, gamma= 81.84(2)degrees, Z=1;[Me2H2N][Ni(dmise)(2)](2) (C14H8NNi2S16Se4), triclinic, P (1) over bar, a=7.625(3)Angstrom, b=17.583(5)Angstrom, c=6.526(2)Angstrom, alpha=100.01(2)degrees, beta=114.81(5)degrees, gamma=80.82(5)degrees, Z=1;[MeH3N][Ni(dmise)(2)](2) (C13H6NNi2S16Se4), monoclinic, P2(1)/c, a=7.636(2)Angstrom, b=9.545(3)Angstrom, c=22.555(6)Angstrom, beta=92.95(2)degrees, Z=2, Shea contacts between Se atoms across the cation sheet were found in [Me3HN][Ni(dmise)(2)](2) and [Me2H2N][Ni(dmise)(2)](2). A tight-binding band structure calculation by extended Huckel methods indicated that [Me3HN][Ni(dmise)(2)](2) has even stronger intermolecular interactions along the long molecular axis than along the transverse direction owing to a close selenium-selenium contact. Cs[Pd(dmise)(2)](2) kept metallic behavior down to 4 K at ambient pressure.