Some co-ordination compounds of TaCl3S and TaBr3S. X-Ray crystal structure of [TaCl3S(PhSCH2CH2SPh)]

Abstract

The reaction of TaX₅(X = Br or Cl) with Sb₂S₃(molar ratio 3 : 1) led to the formation of TaX₃S. With L these species form complexes of formulation TaX₃S·2L (L = dimethyl sulphide, tetra-hydrothiophene, or MeCN) and TaX₃S·L [L = bpte = 1,2-bis(phenylthio)ethane]. The exact nature of the complexes was ascertained by a single-crystal X-ray study on TaCl₃S·bpte. The crystals are monoclinic, space group P2₁/c, Z= 4 with a= 15.538(20), b= 7.352(8), c= 16.619(20)Å, and β= 110.88(10)°. 2 003 Independent reflections with I > 4σ(I) were used in the refinement and a R value of 0.062 obtained. The structural study showed that the metal atom was in a distorted octahedral environment with a terminal TaS bond [2.204(5)Å], three metal–chlorine interactions [2.322(5), 2.366(5), and 2.241 (6)Å], and two bonds to the sulphur atoms of the ligand. The bond trans to the terminal sulphur atom is longer [2.836(4)Å] than the bond that is cis[2.705(5)Å]. The TaS fragment has the expected influence on the three angles it forms at the metal with the three chlorine atoms that are bound cis to it, increasing the angles to ca. 100°. This is concomitant with a surprisingly small value of 86.5(2)° for the angle STa–S(cis).