Niobium(IV) sulphidohalides: preparation of Nb2X4S3 and Nb2X4S3·nL [X = Br or Cl; n= 4, L = NCMe, SMe2, or tetrahydrothiophene (tht); n= 2, L = PhSCH2CH2SPh]. Crystal and molecular structure of Nb2Cl4S2·4tht

Abstract

The niobium(IV) compounds Nb₂Cl₄S₃(X = Br or Cl) were formed by the reaction of NbX₅ and Sb₂S₃(2 : 1 molar ratio) in CS₂ at 50 °C. These species contain the [[graphic omitted]]⁴⁺ moiety. A range of adducts Nb₂X₄S₃·nL [n = 4, L = NCMe, SMe₂, or tetrahydrothiophene (tht); n= 2, L = PhSCH₂CH₂SPh] were prepared and Nb₂Cl₄S₂·4tht was obtained from Nb₂Cl₄S₃·4tht by the abstraction of a sulphur atom with PPh₃. A crystal of Nb₂Cl₄S₂·4tht was found to be monoclinic, space group P2₁/n, with a= 19.958(11), b= 12.616(8), c= 11.530(10)Å, β= 97.0(1)°, and Z= 4. 2 741 Independent reflections above background were measured on a diffractometer and the structure refined to R 0.053. The structure is dimeric with two niobium atoms [Nb–Nb 2.868(2)Å] being linked by bridging sulphur atoms. Each metal atom is six-co-ordinate being bound to two chlorine atoms and two ligand sulphur atoms as well as the bridging atoms.