SYNTHESIS AND CRYSTAL-STRUCTURE OF NB2S4(S(2)NCET(2))(4), THE FIRST MOLECULAR-COMPLEX CONTAINING AN [NB-2(MU(2)-S-2)(2)](4+) FRAGMENT

The crystal structure war determined for Nb2S4(S(2)NCEt(2))(4) obtaine d in 48% yield by the reaction of Cs4Nb2S4(NCS)(8) with NaS(2)CNEt(2) in water: a = 21.181(8), b = 6.958(1), c = 16.623(6) Angstrom, beta = 133.95(2)degrees, V = 1764(1) Angstrom 3, space group C2/m, Z = 2, d(c alc) = 1.708 g/cm(3). The measurements were carried out on a Syntex P2 (1) diffractometer with CuKalpha radiation. A total of 2536 reflection s were measured, of which 990 were used, R(aniso) = 0.0444. The basic fragment in this molecule is [Nb-2(mu(2)-S-2)(2)](4+), the Nb-Nb dista nce in which corresponds to a metal-metal single bond. The molecule is partially disordered over two positions about the twofold axis and mi rror plane of the C2/m space group. The dithiocarbamate and disulfide ligands with bidentate coordination form a distorted square antiprism about each of the niobium atoms as in NbS2Cl2. The anomalously large S -S bond length in the S-2 ligand [2.282(5) Angstrom] may be attributed to inaccuracy in the determination due to disorder.