Preparations, Properties, and Crystal and Molecular Structures of the Cyanomethane Adducts of Niobium(IV) Chloride and Di-μ-sulphido-bis

Article abstract of DOI:10.1039/DT9810001304

The cyanomethane adduct of NbCl4 analyses for NbCl4*3CH3CN (1).A crystal-structure determination of this species shows that it contains cis octahedral and a solvent CH3CN molecule.The unique bond lengths are Nb-N 2.220(13) Angstroem and Nb-Cl 2.328(2),2.343(6), and 2.349(4) Angstroem.The crystals of (1) are orthorhombic with unit-cell dimensions a=10.437(11), b=13.883(12), c=9.828(9) Angstroem, Z=4, and space group Pnma.A total of 729 reflections above background have been collected on a diffractometer and refined to R 0.051.When the cyanomethane adducts of NbX4 (X=Cl or Br) are treated with Sb2S3 in cyanomethane, adducts of NbX2S (X=Cl or Br) are formed.The products contain <2> in which there is a ring.The crystal structures of two compounds, (2) and (3), containing the <2> dimeric unit have been determined.In (2) there are two molecules of occluded CH3CN for each dimer while (3) has one.Both (2) and (3) are triclinic with space group P<*>, with (2) having a=9.031(7), b=9.367(6), c=8.360(8) Angstroem, α=108.72(9), β=94.93(7), γ=105.70(8) degree, Z=1 and (3) having a=14.965(18), b=8.838(17), c=9.543(23) Angstroem, α=112.42(18), β=84.39(28), γ=103.65(21) degree, z=2.For (2), 1434, and for (3), 1530, independent reflections above background have been collected on a diffractometer and refined to R 0.056 and 0.050 respectively.The dimer configurations in (2) and (3) are identical.The niobium atoms are in a pseudo-octahedral enviroment consisting of two cis sulphur, two trans chlorine , and two cis nitrogen atoms .In addition, in each dimer there is a Nb-Nb single bond <2.862(29-2.872(3) Angstroem>.

Full text of DOI:10.1039/DT9810001304

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